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  • 2005-2009
  • 1970-1974  (23)
  • 1965-1969  (28)
  • 1960-1964
  • 1930-1934
  • 1905-1909
  • 1971  (23)
  • 1969  (28)
  • Cat
  • 1
    Digitale Medien
    Digitale Medien
    Dendrodendritic synapses of cells that have axons: The fine structure of the Golgi type II cell in the medial geniculate body of the cat (1971)
    Springer
    Anatomy and embryology 133 (1971), S. 216-246 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Neurocytology ; Synapse ; Audition ; Thalamus ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This study provides a combined analysis with the Golgi method and electron microscopy of the Golgi type II cells of the thalamus in the cat. In the ventral nucleus of the medial geniculate body these cells constitute a large, morphologically homogeneous population of neurons. They are clearly distinguished from the thalamo-cortical neurons by their size, shape, kinds of dendritic appendages, and cytoplasmic structure. The axon of the Golgi type II cell is exceptionally short and forms a small number of lumpy endings in the vicinity of its origin. The dendrites are often longer and much more elaborately branched than the axon. The shafts of these dendrites bear spiculated appendages, while the distal ends of the dendrites form clusters of very large endings. The appendages and terminal clusters participate in the nests of axonal endings formed by the afferent auditory axons and the dendritic branches of thalamo-cortical neurons. These axonal nests are the synaptic nests observed in electron micrographs. Within the synaptic nests the endings of Golgi type II neurons form dendrodendritic synapses on the dendrites of the thalamocortical neurons. The dendritic endings of Golgi type II neurons also receive synapses from the afferent axons. The dendrodendritic synapses may involve the Golgi type II neurons in an inhibitory role in the thalamo-cortical transformation of auditory signals. The dendrodendritic endings of the Golgi type II neurons continue to grow in the adult cat. Possibly these cells are involved in the evolution of cortical functions and in the plastic changes of neural activities that modify behavior.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00528025
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  • 2
    Digitale Medien
    Digitale Medien
    Early prenatal ontogenesis of the cerebral cortex (neocortex) of the cat (Felis domestica). A Golgi study (1971)
    Springer
    Anatomy and embryology 134 (1971), S. 117-145 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Prenatal ontogenesis ; Neocortex ; Cat ; Golgi study
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The neocortex of the cat undergoes a series of fundamental transformations of its fibrillar-neuronal organization during the course of early prenatal cortical ontogenesis. Some of these transformations assume structural chracteristics and neuronal features which resemble those of phylogenetically older cortical organizations. Following the arrival of corticipetal fibers at the marginal zone of the cerebral vesicle a very primitive neocortical organization, the primordial plexiform layer develops. It is characterized by the external location of the white matter with both corticipetal and a few corticofugal fibers and a few immature neurons sandwiched between the fibers. The primitive plexiform layer is present in the cat from the 20th to the 25th day of gestation. The external (superficial) location of the white matter of the primordial plexiform layer of the cat neocortex is reminiscent of the amphibian cortical organization. It also resembles other primitive structures (spinal cord) of the central nervous system. In view of its short duration and because of the immaturity of its fibrillar-neuronal elements, the primordial plexiform layer is considered to be a transient neocortical organization possibly without functional activity in the cat. The appearance of the cortical plate (25th day of gestation) causes the subdivision of the primordial plexiform layer into an outer and an inner zone. The outer zone becomes layer I and the inner zone layer VI of the neocortex. Both of these layers remain as such throughout cortical development. From the 25th to the 45th day of gestation the fibrillarneuronal structure of layers I and VI develop while the cortical plate grows, passively, by the progressive addition of new cells. The progressive fibrillar-neuronal organization of layers I and VI and the development of structural and functional interactions between them constitutes the primordial neocortical organization of the cerebral cortex of the cat. It is characterized by a superficial (layer I) and a deep (layer VI) plexiform layer composed predominantly of collaterals from the corticipetal fibers arriving at the developing cortex and by three basic types of neurons. The horizontal neurons of layer I with descending axons terminating in layer VI, and the Martinotti neurons of layer VI with ascending axons terminating in layer I, are associative neurons. The large stellate neurons of layer VI are projective neurons. The axons of these cells before entering the white matter send ascending recurrent collaterals to layer I. The fibrillar-neuronal organization of the neocortex during this gestational period (primordial neocortical organization) resembles the organization of the reptilian neocortex. It is postulated that the primordial neocortical organization of the cat is functionally active during this gestational period. The arrival of new types of afferent fibers at the lower region of the cortical plate (45th day of gestation) causes the maturation of the pyramidal neurons of this region of the neocortex. These neurons are recognized at this age as the pyramidal neurons of layer V of the neocortex of the cat. The appearance of these afferent fibers and the maturation of the pyramidal neurons of layer V marks the transformation of the neocortex from its primitive reptilian structure into a distinctly mammalian organization. It is postulated that the cortical plate (pyramidal plate) is a recent addition in neocortical phylogeny representing a mammalian transformation. An analogy seems to exists among the pyramid-like neurons of the amphibian cortex, the pyramid-like neurons of the reptilian neocortex and the pyramid-like neurons (stellate) of layer VI of the mammalian neocortex. This analogy differs from the classical one postulated by Cajal which includes the pyramidal neurons of the mammalian neocortex, which are here considered as recent additions to neocortical phylogeny and hence as distinct mammalian neurons.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00519296
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  • 3
    Digitale Medien
    Digitale Medien
    Origin and termination of cuneocerebellar tract (1971)
    Springer
    Experimental brain research 13 (1971), S. 339-358 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cuneocerebellar tract ; External cuneate nucleus ; Main cuneate nucleus ; Cerebellum ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. The origin and termination was determined for cells belonging to the cuneocerebellar tract in the cat, which consists of one proprioceptive component (P-CCT) activated by group I muscle afferents and one exteroceptive component (E-CCT) activated by cutaneous afferents. The recording sites of the cells were histologically verified and the termination of the axons assessed by antidromic activation from the cerebellar surface. 2. The P-CCT originates from cells in the external cuneate nucleus, where forelimb muscles are somatotopically represented. The observations suggest that practically all cells in this nucleus project to the cerebellum and are activated by muscle afferents. 3. The E-CCT originates from cells in the rostral part of the main cuneate nucleus, where they occur intermingled with lemniscal neurones. 4. The CCT terminates in the pars intermedia of lobule V of the anterior lobe and in the four rostral folia of the paramedian lobule. The majority of the cells send one branch to each projection area. 5. The P-CCT and E-CCT terminate in the same projection areas. 6. CCT neurones activated from distal and proximal parts of the limb terminate diffusely in the entire projection area, although there is some tendency for neurones activated from distal parts to terminate caudally and for neurones activated from proximal parts to terminate rostrally.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234336
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  • 4
    Digitale Medien
    Digitale Medien
    Optic nerve axon diameters measured in the cat retina: Some functional considerations (1971)
    Springer
    Experimental brain research 13 (1971), S. 498-503 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Optic nerve ; Retina ; Axon diameters ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Because of the arrangement of axon bundles in the fibre layer of the cat's retina, it is possible to obtain electronmicroscopic sections of axon bundles which contain exclusively either axons arising from the area centralis, or axons arising from peripheral retina. From electronmicrographs of such sections we have constructed axon diameter spectra for central and peripheral axon samples. The centrally originating axons are markedly smaller than peripheral axons, in good agreement with their slower conduction velocity (described in an accompanying paper). The diameter spectra of both peripheral and area centralis axon samples are unimodal, in contrast to the two conduction velocity groups known to exist within each axon population. Alternative explanations of this discrepancy between diameter and conduction velocity spectra are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234280
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  • 5
    Digitale Medien
    Digitale Medien
    Excitation and depression of cortical neurones during spreading depression (1971)
    Springer
    Experimental brain research 12 (1971), S. 132-149 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cerebral cortex ; Spreading Depression ; Glutamic acid ; Excitation ; Depression ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Variations in the excitability of individual cortical neurones during the invasion of spreading depression (SD) have been monitored by observing the alterations of spontaneous and L-glutamate-induced firing. Invasion of many neurones during SD is marked by a brief burst of firing which occurs concurrently with the onset of the negative slow extracellular potential. Other neurones do not fire, although the microelectrode records a negative slow wave. Depression of glutamate-induced and spontaneous firing follows and may last for several minutes. The initial loss of excitability of those neurones that discharge during SD invasion may be due to excessive depolarization. This phase is rapidly succeeded by a period of depressed excitability, during which the neurones can be invaded by an antidromic spike or excited by increased amounts of L-glutamate. These findings indicate that SD propagation initially involves the release of an excitant substance, possibly glutamic acid. The continuing effects of SD are due to the reduction in cell excitability. As many neurones are depressed without undergoing an initial excitation, it appears that a depressant substance is also involved. This may be gamma-aminobutyric acid.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234311
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  • 6
    Digitale Medien
    Digitale Medien
    Excitability changes of extensor motoneurons and primary afferent endings during prolonged stimulation of flexor afferents (1971)
    Springer
    Experimental brain research 12 (1971), S. 150-160 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Monosynaptic response ; Primary afferent depolarization ; Spinal cord ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Long trains of electrical stimuli supramaximal for Group I fibers of PBST nerves were used to study the effect on GS pathway. Inhibition of GS monosynaptic response occurred during PBST stimulation: however, decline in the inhibition developed with time despite the constancy of the inhibitory input monitored from the dorsal root. The level of recovery of the monosynaptic reflex at steady state depended upon the frequency of PBST stimulation, the higher the frequency the more complete the recovery. The effect of increasing the frequency of GS stimulation was to increase the inhibitory effect from PBST. Enhanced excitability of GS primary afferent endings in monosynaptic contact with homonymous motoneurons occurred and decreased parallel to the recovery of the monosynaptic response. When present, the polysynaptic response evoked by stimulating GS peripheral nerves increased during PBST stimulation in an inverse relation to changes in the monosynaptic response. Intracellular recordings from GS motoneurons usually revealed no change in membrane potential or in excitability of postsynaptic membrane to direct stimulation. Increased delay of intracellular GS spike potential was observed during PBST stimulation. The amount of this shift can be accounted for by polysynaptic activation of the same motoneuron.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234312
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  • 7
    Digitale Medien
    Digitale Medien
    Observations on synaptic patterns in the dorsal lateral geniculate nucleus of the cat: The C laminae and the perikaryal synapses (1971)
    Springer
    Experimental brain research 12 (1971), S. 184-203 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Lateral geniculate ; Cat ; Synapse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The laminae near the optic tract which have previously been described as C, C1 and C2, have been studied electron microscopically and compared ] to the A laminae. In the A laminae most of the presumed retinogeniculate axons end in encapsulated synaptic zones that contain multiple interconnected synaptic profiles. Only a few of these axons form simple axodendritic synapses upon proximal dendritic segments of the largest cells. In the C laminae the situation is reversed. Most of the retinogeniculate axons end as simple synapses upon medium or small dendrites and few end in encapsulated synaptic zones. Further, these zones are simpler in the C laminae than in the A laminae. The neuronal profiles are smallest and the synaptic interconnections appear to be least complex in lamina C2, where there are only a few, small, presumed retinogeniculate terminals. Of the three C laminae, lamina C, furthest from the optic tract, shows the largest profiles and the most complex interconnections. Bundles of very fine axons occur in all the laminae, but they dominate the regions closest to the optic tract (lamina C2) where they tend to run parallel to the lamina. Some of the largest cells in laminae A, A1 and C are contacted by very fine perisomatic axons which contain round vesicles. These axons have not been described before and are likely to represent an input too fine to have been demonstrable by light microscopical methods.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234315
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  • 8
    Digitale Medien
    Digitale Medien
    The termination of the spinothalamic tract in the cat an experimental study with silver impregnation methods (1971)
    Springer
    Experimental brain research 12 (1971), S. 331-353 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Spinal cord ; Thalamus ; Silver methods ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The termination of the spinothalamic tract (STT) in the cat has been studied light microscopically in Fink-Heimer and Nauta impregnated sections. Following lesions of the STT at various rostrocaudal levels of the spinal cord the degenerating fibres in the thalamus and subthalamus were mapped, mainly in transverse sections. The cervicothalamic tract was not injured by the lesions. The spinothalamic fibres enter the diencephalon through the mesencephalic reticular formation and terminate in the following regions: the medial portion of the magnocellular part of the medial geniculate body (MGmc), the ventrolateral portion of the medial part of the posterior nuclear complex (POm), the caudolateral and medial parts of the zona incerta (ZI), the nucleus centralis medialis (CeM), the nucleus parafascicularis (Pf), the lateral part of the nucleus centralis lateralis (CL), the medial and rostrolateral parts of the nucleus ventralis lateralis (VL). To reach these regions the fibres pass through the nucleus centrum medianum (CM), the nucleus subparafascicularis (SPf) and the nucleus paracentralis (Pc). The fibres that terminate in the VL pass through Forel's field H1 and the external medullated lamina (EML). Conclusive results were not obtained concerning a termination in the CM. The spinothalamic fibres do not pass through nor terminate in the nucleus ventralis posterolateralis (VPL) and the nucleus reticularis (R). The VPL, defined as that portion of the ventral thalamus that receives terminal fibres from the dorsal column nuclei, has been found to extend rostrally only as far as Horsley-Clarke level anterior 10.5. The results strongly support the view that all the spinothalamic fibres terminate ipsilateral to their course in the ventral quadrant of the spinal cord. No signs of a somatotopical organization of the termination of the STT were found.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234489
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  • 9
    Digitale Medien
    Digitale Medien
    Modification of the distribution of receptive field orientation in cats by selective visual exposure during development (1971)
    Springer
    Experimental brain research 12 (1971), S. 509-527 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Visual cortex ; Receptive fields ; Visual deprivation ; Neuronal plasticity ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A novel procedure was used to rear kittens under conditions of controlled visual experience: one eye was exposed only to vertical lines while the other eye, simultaneously, was exposed only to horizontal lines. Stimuli were presented in a mask which the animals wore whenever they were in a lighted environment. At the conclusion of the rearing period elongated receptive fields of units recorded from the visual cortex of these animals were oriented either horizontally or vertically. This is in contrast to the full complement of receptive field orientations found in normal cats. Furthermore, units with vertically oriented fields were predominantly or exclusively activated by the eye which had been exposed to vertical lines, while neurons with horizontally oriented fields were predominantly or exclusively activated by the eye which had been exposed to horizontal lines. Normally, 80–90% of the neurons in the visual cortex of the cat are activated by both eyes. The consequences of this controlled visual experience provide evidence for highly selective modification of neuronal connectivity by environmental conditions prevailing during development. Sufficient control of the visual environment was achieved to allow direct comparison between single unit response characteristics and the specific stimuli presented during rearing.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234246
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  • 10
    Digitale Medien
    Digitale Medien
    Effects of fenfluramine on sleep-wakefulness in cats (1971)
    Springer
    Psychopharmacology 20 (1971), S. 1-9 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Fenfluramine ; Amphetamine ; Paradoxical Sleep ; Slow-Wave Sleep ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Five cats were prepared with chronically implanted electrodes for recording sleep-wakefulness patterns. Four of these animals received fenfluramine at each of three dose levels and data was recorded for the following 12 hours. Percent of time in paradoxical sleep was significantly reduced by 2.5 and 7.5 mg/kg, but not by 0.5 mg/kg, of fenfluramine. The higher doses also increased slow-wave sleep and, at 7.5 mg/kg (an anorexigenic dose), total sleep time was significantly increased. Under similar conditions amphetamine, at an anorexigenic dose of 1 mg/kg, significantly suppressed both paradoxical sleep and slow-wave sleep in three cats. Rebound of paradoxical sleep after suppression induced by 2.5 mg/kg of fenfluramine was not seen in either of two cats studied when sleep patterns were recorded for 48 hours. After 7.5 mg/kg of the drug, however, rebound was seen on days 3 and 4 after suppression of paradoxical sleep which lasted for over 26 hours. In two animals, daily administration of 2.5 mg/kg of fenfluramine for 16 consecutive days, followed by saline administration for three days, indicated that tolerance was developing to the suppression of paradoxical sleep produced by the drug.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00404052
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  • 11
    Digitale Medien
    Digitale Medien
    Mossy and climbing fibre activation in the cat cerebellum by stimulation of the labyrinth (1971)
    Springer
    Experimental brain research 12 (1971), S. 1-17 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Purkinje cell ; Mossy fibres ; Climbing fibres ; Vestibular system ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In decerebrate cats, caloric and galvanic stimulations of the labyrinth were able to modulate the activity of the Purkinje cells through both the afferents which terminate in the cerebellar cortex as mossy fibres and climbing fibres. In response to these stimulations, several patterns of response were seen. For the galvanic stimulation a predominant pattern was described. In most cases the mossy fibre driven activity had an effect which was opposite to that of the climbing fibre one. The climbing fibre driven activity could be modulated only in the low frequency range, but it can interfere remarkably with the mossy fibre one. The results described were obtained not only in the so-called vestibular area of the cerebellum, but also in other areas.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234413
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  • 12
    Digitale Medien
    Digitale Medien
    Organization of afferent connections to cuneocerebellar tract (1971)
    Springer
    Experimental brain research 13 (1971), S. 359-377 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cuneocerebellar tract ; Proprioceptive path ; Exteroceptive path ; Cerebellum ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. The afferent connections to 180 cuneocerebellar tract (CCT) neurones were studied in the cat. The neurones were classified into two groups, proprioceptive and exteroceptive. 2. The proprioceptive neurones (P-CCT) occurred in the external cuneate nucleus and were monosynaptically activated by group I muscle afferents. About 60% of these neurones received additional excitation from group II muscle afferents. 3. The P-CCT neurones received excitation from one nerve only. 4. The P-CCT neurones received postsynaptic inhibition from muscle nerves not supplying excitation. 5. The exteroceptive neurones (E-CCT) occurred in the main cuneate nucleus and received di- and polysynaptic excitation from cutaneous afferents. Most neurones received additional excitation from high threshold muscle afferents. The latter originated from receptors that were sometimes activated by pressure against deep structures but seldom, if ever, from slowly adapting stretch receptors in muscle. 6. The E-CCT neurones were usually activated from several skin and muscle nerves. 7. Stimulation of the sensorimotor area of the cerebral cortex evoked inhibition in some P-CCT neurones and excitation and/or inhibition in some E-CCT neurones. 8. The afferent organization of the CCT is compared with that of the dorsal spinocerebellar tract. The information carried by the two tracts is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234337
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  • 13
    Digitale Medien
    Digitale Medien
    Conduction velocity groups in the cat's optic nerve classified according to their retinal origin (1971)
    Springer
    Experimental brain research 13 (1971), S. 489-497 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Conduction velocity ; Cat ; Retina ; Optic nerv
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary By recording antidromic field potentials and unit responses generated in the retina by stimulation of the optic tract and optic disc, evidence was obtained which suggests the presence of four major conduction velocity groups in the cat's optic nerve. The axons from all peripheral retina appear to fall into two groups, fast and slow, which correspond to the two major velocity groups described by earlier workers. Evidence is presented that the axons which arise from the area centralis form two distinctly slower conduction velocity groups. For each conduction velocity group, and for 60 single units, conduction velocity was estimated for both the intraretinal (unmyelinated) and extraretinal (myelinated) segments of the axons. All axons encountered accelerated markedly on leaving the retina. An anatomical basis for the classification of conduction velocity groups is presented in an accompanying paper.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234279
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  • 14
    Digitale Medien
    Digitale Medien
    Lateral geniculate unit activity and eye movements: Saccade-locked changes in dark and in light (1971)
    Springer
    Experimental brain research 13 (1971), S. 533-546 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Lateral geniculate body ; Eye movements ; Corollary discharge ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The activity of 83 single lateral geniculate body (LGB) neurons was recorded in encéphale isolé cats, during nystagmic eye movements induced as an after-effect of electrical stimulation of the lateral vestibular nucleus. Phasic changes in firing, time-locked with the eye movements were found in 66% of the neurons, by a method using the saccades to trigger a post-“saccadic”-time histogram of the corresponding neuronal discharge. In 51% of the neurons, a saccadelocked change was significant even in complete darkness. The onset of the postsaccadic change showed an average latency of about 100 msec from the onset of the movement. The change could be either an increase, or a decrease in firing in both light and dark, or a change evident in one condition only, or even a reversal of the pattern of the change by shifting from one condition to the other. The results are discussed in connection with theories on visuo-motor mechanisms that counteract illusory shifts of visual field during active eye movements. The saccadelocked influences on LGB dark activity strongly support the Helmholtz-Teuber notion of “corollary discharges” modifying the activity of visual centers during eye movements.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234284
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  • 15
    Digitale Medien
    Digitale Medien
    Influence of stimulation of the cerebral cortex on vestibular nuclei units in the cat (1971)
    Springer
    Experimental brain research 14 (1971), S. 77-94 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Vestibular nuclei units ; Descending influence from cortical areas 2 pri and 6aδ ; Converging multisynaptic pathway ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In cats under subhypnotic doses of a-chloralose and pentobarbital the descending action of circumscribed cortical stimulation on the unit activity in the vestibular nuclei was investigated. From a total of 215 units distributed through the middle areas of the vestibular nuclei, 61 units responded — 59 with facilitation and 2 with inhibition. No discernible relationship between units responding to horizontal rotation and those responding to cortical stimulation was demonstrated. Most responsive neurons within the vestibular nuclei were in the internal part of the triangular and the parvocellular and ventral subdivisions of Deiters' nucleus, whereas its dorsal part and the medial vestibular nucleus were virtually free of cortically excitable units. Stimulation of both ipsilateral and contralateral area 2 pri, on the anterior ectosylvian gyri, and area 6aδ, hidden in the cruciate sulcus, was effective, while stimulation of the surface parts of area 6 and of area 4 was not. This response may be conducted via converging multisynaptic pathways to a midbrain area, possibly to the nuclei of the direction-specific eye and head movements, and from there to the vestibular nuclei.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234912
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  • 16
    Digitale Medien
    Digitale Medien
    Methamphetamine effects upon avoidance behavior during limbic seizures in the cat (1971)
    Springer
    Psychopharmacology 21 (1971), S. 390-400 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Methamphetamine ; Septal Stimulation ; Limbic Seizures ; Septal after-Discharge ; Shock Avoidance ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract It was predicted that methamphetamine administered to nine adult male cats would counteract the debilitating effects of electrically-induced septal after-discharges (seizures) upon learned shock avoidance. Performance was assessed in terms of number of avoidance responses and their latencies. Septal after-discharges of over five seconds duration resulted in the predicted deterioration of avoidance performance. Under the dosage (1.5 mg/kg) and conditions employed in the present experiment, methamphetamine appeared to enhance, rather than counteract, this effect. Methamphetamine alone had mixed effects upon avoidance behavior: there was less tendency for animals to “freeze” in response to the CS, but subjects appeared confused and disoriented. There was a greater likelihood of occurrence of after-discharges when methamphetamine was used in conjunction with electrical stimulation of the septum.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02419062
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  • 17
    Digitale Medien
    Digitale Medien
    Carotid body oxygen consumption of the catin vitro (1971)
    Springer
    Pflügers Archiv 323 (1971), S. 315-322 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Chemoreceptors ; Carotid Body ; Cat ; Oxygen Consumption ; Schlüsselwörter ; Chemoreceptoren ; Glomus caroticum ; Katze ; Sauerstoffverbrauch
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The oxygen consumption of the cat carotid body has been measuredin vitro using a confinement method. The oxygen consumption of the organ appears to be very high (1.14 ml STPD·min−1 per gram of dried tissue). The carotid body dry mass (0.044 mg) was much lower than the values found in the literature. The O2 consumption versus O2 tension relationship of this small organ shows no critical points as other organs generally do.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00592402
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  • 18
    Digitale Medien
    Digitale Medien
    Changes in firing rates of extensor motoneurones caused by electrically increased spinal inputs (1971)
    Springer
    Pflügers Archiv 326 (1971), S. 35-47 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Extensor Motoneurones ; Synaptic Activation ; Inhibition ; Spinal Cord ; Cat ; Extensor-Motoneuren ; Synaptische Erregung ; Hemmung ; Rückenmark ; Katze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. Veränderungen in repetitiven Entladungsmustern der extensor Alpha-Motoneuren während afferenter Tetanisationen mit verschiedenen Reizstärken und Reizfrequenzen wurden bei decerebrierten Katzen untersucht. 2. Die Motoneuren wurden durch Teilung der Ventralwurzeln bei Tetanizationen des ipsilateralen N. gastrocnemius mit 100–200 Hz funktionell isoliert. Nach Amplituden der extracellulär abgeleiteten Spikes wurden die Motoneuren zu “großen” und “kleinen” angeordnet. Die Anzahl der aktivierten afferenten Fasern wurde durch die Steigerung der Reizstärke gesteigert. 3. Kleine Motoneuren waren immer tonisch; große Motoneuren waren im allgemeinen phasisch, selten tonisch. Die Schwelle für tonische Entladungen lag höher bei großen Motoneuren als bei kleinen. 4. Hochfrequente Tetanisationen (150–200 Hz) des N. gastrocnemius verursachte eine Aktivitätsabnahme bei großen Motoneuren; dabei blieb die Entladungsfrequenz der kleinen Motoneuren unverändert oder war öfters leicht gesteigert. 5. Die Steigerung der Zahl der tetanisierten afferenten Fasern bei unveränderten Reizfrequenzen verursachte eine Abnahme des Entladungsrates der kleinen tonischen Motoneuren oder wandelte sie zu den phasischen um; die Entladungsfrequenz der großen Motoneuren wurde durch diese Prozedur gesteigert. 6. Möglichkeiten, welche die Unterschiede in Entladungsmustern der großen und kleinen Motoneuren während afferenter Tetanisationen mit verschiedenen Reizstärken und Reizfrequenzen verursachen können, werden diskutiert.
    Notizen: Summary 1. Variations in repetitive firing patterns of extensor alpha motoneurones caused by afferent tetanizations at different intensity and frequencies were investigated in decerebrated cats. 2. Motoneuronal units were isolated by dividing ventral roots and tetanization of the ipsilateral gastrocnemius nerves with 100–200 Hz. The amplitude of extracellularly recorded spikes of motoneurones was used for classifying them as “large” or “small”. The number of activated afferent fibres was increased by increasing the stimulus intensity. 3. Small-amplitude motoneuronal units were always tonic; large-amplitude motoneuronal units were generally phasic, rarely tonic. The threshold for tonic firing was higher in large-amplitude units than in small-amplitude units. 4. High frequency afferent tetanization (150–200 Hz) caused depression in activities of large-amplitude motoneuronal units; discharge frequencies of small-amplitude motoneuronal units remained unchanged or were often slightly increased during such stimulations. 5. Increasing the number of afferent fibres tetanized at unchanged frequencies caused a decrease in firing rates of tonically discharging small-amplitude motoneuronal units or changed them to a phasic type of motoneurones; discharge frequencies of large-amplitude motoneuronal units were increased by this procedure. 6. Possibilities which can cause the differences in firing patterns of small- and large-amplitude motoneuronal units during afferent tetanizations at various stimulus intensities and frequencies are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00586793
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  • 19
    Digitale Medien
    Digitale Medien
    The lateral cervical nucleus in the cat (1971)
    Springer
    Cell & tissue research 115 (1971), S. 377-387 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Lateral cervical nucleus ; Cat ; Quantitative study ; Ultrastructural investigation-Neuron
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Profiles of 14 neurons all sectioned through the nucleolar plane and 87 isolated dendritic profiles have been analyzed with respect to the surface area covered by boutons and astroglial processes. This analysis has revealed two different types of neurons within the lateral cervical nucleus (LCN) of the cat. The cell types also differ in other ultrastructural respects. One type, which probably consists of projection neurons, is characterized by a rather large size, a relatively small nucleus, numerous mitochondria, well developed granular and agranular endoplasmic reticulum. The cell membrane of these cells shows somatic spines and the perikaryon is covered with boutons to a mean extent of 42%. The other cell type, which probably is internuncial, is smaller, has a proportionally larger nucleus, few mitochondria and a poorly developed granular and agranular endoplasmic reticulum. These cells show no somatic spines and the perikaryal membrane is covered with boutons to an extent of about 10%. Also the bouton populations contacting the two cell types differ from one another. The proportion of internuncial neurons within the LCN has been estimated to about 8%. The internuncial neurons seem to have no preferential localization. The primary dendrites of the projection neurons have a bouton covering of about 48%. No proportional differences in covering could be revealed between different sizes of dendrites. The results are discussed in relation to what is known about the anatomical and physiological organization of the LCN, and also compared with the results obtained in other similar investigations on other parts of the central nervous system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00324940
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  • 20
    Digitale Medien
    Digitale Medien
    The synaptic organization in the medial geniculate body of afferent fibres ascending from the inferior colliculus (1971)
    Springer
    Cell & tissue research 113 (1971), S. 44-66 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Ventral nucleus of medial geniculate body-Synaptic patterns ; Experimental degeneration ; Collicular afferents ; Cell laminae ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ventral nucleus of the medial geniculate body has been examined electron microscopically 2–5 days after destruction of the inferior colliculus. In both the ipsi- and contralateral ventral nuclei, degenerating collicular afferents are of medium diameter (1–5 μ) and their degenerating terminals are distributed mainly to synaptic aggregations (“glomeruli”) in which they end axo-axonically and axo-dendritically. Their distribution and mode of termination indicates that these terminals belong to a class which in normal material is large, contains round synaptic vesicles and ends by means of asymmetrical synaptic complexes upon dendrites and upon the second (“pale”) type of glomerular terminal. It also ends by means of “adhesion plaques” on the same dendrites. As the terminals of corticothalamic afferents to the nucleus are already known, only the origin of two types remains to be determined: the pale terminals, which arise from structures resembling dendrites and which end only axo-dendritically, and a small, less common terminal which ends axo-axonically, axo-dendritically and axo-somatically. Both types contain flattened synaptic vesicles and end by means of symmetrical synaptic complexes. Correlative Nauta and Golgi studies suggest that the collicular afferents have a very specific spatial distribution within the cellular laminae composing the ventral nucleus. The terminal degeneration commences as a neurofilamentous hyperplasia and quickly passes to one of increased electron density. There is evidence for early removal of degenerating terminals from the postsynaptic membrane.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00331201
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  • 21
    Digitale Medien
    Digitale Medien
    Beitrag zur Kenntnis der Glomera coronaria der Katze (1971)
    Springer
    Cell & tissue research 118 (1971), S. 532-554 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Glomera coronaria ; Cat ; Chemoreceptor cell ; Blood supply ; Synapses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Gefäße der zwischen Aorta ascendens und Truncus pulmonalis, an der Vorder- und Hinterwand des Truncus pulmonalis gelegenen Glomera, sowie das sogenannte „Glomus pulmonale“ der Katze lassen sich von den Coronararterien aus durch Tusche-Gelatine-Lösungen füllen. Die erwähnten Paraganglien sind als Chemoreceptorenfelder dem Coronarkreislauf angeschlossen und daher als Glomera coronaria zu bezeichnen. Licht- und elektronenmikroskopische Untersuchungen ergaben eine morphologische Übereinstimmung mit dem Glomus caroticum. Vagusdurchtrennungen verursachen eine Degeneration der an den Glomuszellen gelegenen synaptischen Formationen sowie Veränderungen in Glomuszellen.
    Notizen: Summary The vessels of the glomera that lie between the aorta and the pulmonary trunk, on the anterior and posterior wall of the pulmonary trunk, as well as the so-called glomus pulmonale of the cat have been injected with gelatine-india ink mixture. The paraganglia mentioned above are associated with the coronary circulation as chemoreceptors and are designated as the glomera coronaria. The investigations demonstrate a morphologic similarity with the glomus caroticum. Section of the vagus causes a degeneration of the synaptic structures on the glomus cells as well as changes in the cells themselves.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00324619
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  • 22
    Digitale Medien
    Digitale Medien
    Effects of estrogen on the cat hypothalamus (1971)
    Springer
    Cell & tissue research 117 (1971), S. 76-86 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Hypothalamus ; Cat ; Estrogen effects ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In this study the ultrastructural features of tissue from the posterior hypothalamic area were investigated. Ovariectomized cats which were either treated with sesame oil placebo or with estrogen for varying periods of time were used. The following observations were noted. 1. The cat that was treated with placebo one month after ovariectomy showed an increase in the number of dense core (granulated) vesicles within neuronal cytoplasm. This observation was not apparent in the cats which were treated with estrogen one month after ovariectomy. 2. In the cat that had been Ovariectomized for two months before treatment with placebo was initiated, axon terminals contained more dense core vesicles than were observed in axonal endings from estrogen-treated cats in the two month ovariectomy group. 3. The tissue from cats that were continuously treated with estrogen for one month after ovariectomy displayed dense-core vesicles in both somata and neuropil. It is suggested that the ultrastructural changes observed were dependent on both the time of initiation and the length of estrogen treatment. 4. It is concluded that the preliminary observations in this study provide anatomical evidence suggesting that estrogen level in the cat may affect the functional activity of the posterior hypothalamic area.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00331103
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  • 23
    Digitale Medien
    Digitale Medien
    Über die Bedeutung des Narkoticums für funktionelle Untersuchungen an der Katzenharnblase (1971)
    Springer
    Clinical and experimental medicine 155 (1971), S. 187-194 
    Details
    ISSN: 1591-9528
    Schlagwort(e): Chloralose ; Urethane ; Bladder function ; Isometric determinations ; Cat ; Chloralose ; Urethan ; Blasenfunktion ; Isometrische Untersuchungen ; Katze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei isometrischen Untersuchungen von Funktionsabläufen an Katzenharnblasen wurde bei 10 mit Urethan und 49 mit Chloralose narkotisierten Tieren eine eindeutige Dämpfung der Blasenfunktion durch Urethan gefunden. Diese trat bereits ab 50 mg Urethan/kg i.v. auf. Für funktionelle Untersuchungen des Blasenwandmuskels wird daher Chloralose 60 mg/kg i.p. empfohlen.
    Notizen: Summary The influence of two anaesthetic agents (urethane and chloralose) on isometrically determined bladder function was compared in the cat. Even if the animal still showed pronounced muscle reflexes urethane (50 mg/kg and more) clearly impaired bladder function in the phase of collection and also the micturition reflex. Chloralose, even when applied in an anaesthetic dose (60 mg/kg i.p.) did not influence bladder function whatsoever. For this reason chloralose is preferable as an anaesthetic agent in functional experiments on the detrusor muscle of the cat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02047607
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  • 24
    Digitale Medien
    Digitale Medien
    Die Bestimmung der intestinalen Resorption von Herzglykosiden durch Messung der3H-markierten Glykoside im Portalvenenblut und in der Darmlymphe bei Katzen (1969)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 264 (1969), S. 406-419 
    Details
    ISSN: 1432-1912
    Schlagwort(e): Intestinal Absorption ; Cardiac Glycosides ; Blood of Portal Vein ; Intestinal Lymph ; Cat ; Intestinale Resorption ; Herzglykoside ; Portalvenenblut ; Darmlymphe ; Katze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. The cardiac glyoosides digitoxin, ouabain, digoxin and peruvosid labelled with3H were injected into tied intestinal loops of anaesthetized cats in situ. The absorbed glycosides were measured in the blood of the portal vein and in the intestinal lymph. At the same time the3H-activity was measured in the blood of the peripheral circulation, in the bile and in the urine. 2. Calculation of the amount of glycosides totally absorbed from the3H-concentration in the blood of the portal vein and the circulation volume (bubble-flow-meter) gave the following absorption rates as a percentage of the administered dose per hour: digitoxin 56%, digoxin 42%, peruvosid 26% and ouabain 10%. 3. The amount of glycosides passing into the lymph during 1 hour was found to be only 0.006 to 0.02% of the amount offered. In lymph3H-activity cannot be measured earlier than 5 min after the administration of the labelled glycosides. The3H-concentration in the lymph did not equal that measured in the blood of the peripheral circulation until at least 1 hour after the administration and always remained below the3H-concentration of the blood in the portal vein. This proportion remained unchanged even if digitoxin was administered as an emulsion in oil instead of an aqueous solution. From the time course of3H-concentration it might be concluded that the glycosides do not pass directly to the lymph after absorption but indirectly by way of the blood. 4. The amount of glycoside excreted in the bile is for peruvosid 15,5% of the amount absorbed, for ouabain 1,9%, for digoxin 1,4% and for digitoxin 0,8%. The3H-activity excreted in urine is very small and can be disregarded. 5. Chromatographic analyses of the bile revealed, that in the case of digoxin, 4/5 of the amount excreted were unchanged, in the case of digitoxin and ouabain 2/3 and in the case of peruvosid only 1/4. In the lumen of the tied intestinal loops and in the tissue of the small intestine the glycosides were hardly metabolised.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01002379
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  • 25
    Digitale Medien
    Digitale Medien
    Über die Gefäßversorgung des Corpus callosum der Katze (1969)
    Springer
    Anatomy and embryology 128 (1969), S. 28-39 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Arterial supply ; Corpus callosum ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung An 27 Katzen beiderlei Geschlechts wurde die Blutversorgung des Corpus callosum untersucht. Dabei wurden folgende Befunde erhoben: Der Balken der Katze wird im Bereich des Rostrum und Genu sowie im vorderen und mittleren Truncuabschnitt aus der Arteria cerebri anterior versorgt und zwar über Äste, die den Arteriae pericallosae und den Arteriae genu corporis callosi entstammen. Diese Äste wurden als Arteriae callosi superiores und inferiores bezeichnet. Lediglich im hinteren Truncusabschnitt und im Splenium erfolgt die Versorgung neben Ästen der A. pericall. auch über solche der Arteriae cerebri mediae und posteriores. Die Blutgefäße treten dolchartig in den Balken ein, teilen sich dann baumartig weiter auf und gehen in ein Capillarnetz über, das in Richtung des Nervenfaserverlaufes ausgezogen ist. Auf in der Literatur bereits bekannte, aber oft vernachlässigte Besonderheiten der Arteria carotis interna und des Circulus arteriosus wird hingewiesen.
    Notizen: Summary In investigations on 27 cats of both sexes, the arterial supply of the corpus callosum was studied. The findings are as follows: In the region comprising rostrum and genu as well as in the fore and middle trunk sections, blood supplied by branches of the arteriae pericallosae and the arteriae genu corporis callosi which originate from the arteria cerebri anterior. These branches were designated arteriae callosi superiores and inferiores. However, in the posterior section of the trunk and in the splenium the blood is supplied by branches of the aa. pericall. and, in addition, by branches of the arteriae cerebri media and posteriores. The blood vessels penetrate the corpus callosum in bayonet fashion, then arborise and finally become a capillary network which is elongated in the direction of the course of the nerve fibres. Attention is drawn to peculiarities of the arteria carotis interna and the circle of Willis which, although known in the literature, are rarely referred to.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00522492
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  • 26
    Digitale Medien
    Digitale Medien
    Quantitative Untersuchungen an Gliazellen im Corpus callosum wachsender Katzen nach Perfusions- und Immersionsfixierung (1969)
    Springer
    Anatomy and embryology 128 (1969), S. 222-234 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Postnatal development ; Fixation ; Neuroglia ; Corpus callosum ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Gehirne von Tieren aus 4 verschieden alten Würfen junger Katzen wurden teils lebensfrisch durch Perfusion, teils nach 24 Std durch Immersion fixiert und für Vergleichsuntersuchungen in Paraffin eingebettet. Bei Betrachtung der Gliazellen des Corpus callosum ergab sich: 1. Nach Perfusionsfixierung sind die Kerne der Gliazellen groß und elliptisch. Sie sind wasserklar und haben eine scharf gezeichnete Chromatinstruktur. Nach Immersionsfixierung 24 Std p.m. sind die Kerne dagegen klein und rund, homogen dunkel gefärbt und haben ein kaum zu erkennendes Chromatingerüst. 2. Nach Perfusionsfixierung sieht man im Balken der ganz jungen Tiere zahlreiche Mitosen. Sie fehlen bei den durch Immersion fixierten Geschwistertieren desselben Wurfes. 3. Die nach verschiedener Fixierung beobachteten Unterschiede in der Form der Gliazellkerne werden durch Messungen der Quer- und Längsachsen erfaßt.
    Notizen: Summary In four litters of young cats, some of the brains were fixed by perfusion and the others by immersion. The material was embedded in paraffin and the neuroglia was investigated in sections through the corpus callosum. It was found that: 1. After fixation by perfusion the nuclei of the glia cells are large and elliptic. The caryoplasm is clear and there is a distinct structure of the chromatin. After fixation by immersion the nuclei of the same cells are small and round. The caryoplasm is dense and the structure of the chromatin is not clearly visible. 2. After fixation by perfusion mitotic figures are present. They are absent in the brains fixed by immersion. 3. Following different fixation, there are differences in the shape of the nuclei of the glial cells. These differences have been investigated in detail by measuring the diameters of the nuclei.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00521281
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  • 27
    Digitale Medien
    Digitale Medien
    The lateral cervical nucleus in the cat IV. A light and electron microscopical study after midbrain lesions with demonstration of indirect wallerian degeneration at the ultra-structural level (1969)
    Springer
    Experimental brain research 7 (1969), S. 51-67 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Lateral cervical nucleus ; Midbrain lesions ; Nauta method ; Ultrastructural investigation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The lateral cervical nucleus (LCN) has been studied with the light and electron microscope after midbrain lesions in kittens of different ages, and in adult cats. It has been shown that nerve cells remain within the contralateral LCN after hemisection of the midbrain. performed on 1 day old kittens. The estimated number of these remaining cells was 3–19% in the different cases. No fibers descending to the LCN from levels rostral to the midbrain could be demonstrated in adult cats with the Nauta technique. A combined Nauta and electron microscopical investigation was performed on kittens operated on at different ages and allowed to survive varying times postoperatively. At the operations the LCN-axons were transected at midbrain level. The Nauta investigation demonstrated silver impregnation of degenerating LCN-neurons on the affected side of the same type as has been described recently in other neuronal systems following axonal transection. The ultrastructural study revealed electron dense degenerating dendrites and probably also nerve cells within the LCN. The dense degenerative changes were very similar to the dense degeneration in terminal boutons following transection of parent axons. The potential value of the findings for electron microscopical research in neuroanatomy is discussed. The results in terms of connections of the LCN are discussed in the light of known anatomical and physiological data of the LCN.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00236107
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  • 28
    Digitale Medien
    Digitale Medien
    Integration konvergierender Afferenzen in der bulbären Formatio Reticularis der Katze (1969)
    Springer
    Experimental brain research 7 (1969), S. 143-157 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Reticular formation ; Convergence ; Inhibition ; Cat ; Chloralose
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. Ein konditionierender corticaler Reiz inhibiert den somatischen Startlereflex bei Katzen unter Chloralosenarkose für eine Dauer von mehr als 200 ms. Die Interaktionen zwischen beiden Reizen laufen in der bulbären und pontinen Formatio reticularis ab. 2. Dem Startlereflex liegt eine polysynaptische Erregungsschleife zugrunde, die die bulbäre und pontine Formatio reticularis durchzieht. Die Resistenz der reticulären Neurone gegenüber repetitiver Stimulation wurde als Kriterium ihrer funktionellen Lokalisation auf dem polysynaptischen Reflexbogen gewertet. 3. Die corticale Inhibition wird im Verlaufe der polysynaptischen Erregungsschleife zunehmend stärker. Neurone, die von den Startlereflexafferenzen direkt erregt werden, werden durch den corticalen Reiz nicht inhibiert. Dies schliebt eine präsynaptische Inhibition der reticulopetalen Fasersysteme aus.
    Notizen: Summary 1. The startle reflex evoked by cutaneous stimulation in cats under chloralose anesthesia is inhibited for more than 200 ms by a conditioning cortical volley. The interaction between the cutaneous and the cortical volley takes place in the bulbar and pontine reticular formation. 2. The startle reflex involves a series of reticular neurones. Resistance to repetitive stimulation has been determined to evaluate the functional localization of each neurone within this polysynaptic path. 3. Inhibition following the cortical volley becomes increasingly more effective along the course of the polysynaptic path and is completed within 5–6 ms. Reticular neurones excited directly by the spino-reticular afferents are not inhibited, thus excluding a presynaptic inhibition of the spinoreticular fibres.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235440
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  • 29
    Digitale Medien
    Digitale Medien
    Inhibitory and excitatory factors influencing the receptive fields of lamina 5 spinal cord cells (1969)
    Springer
    Experimental brain research 9 (1969), S. 284-306 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cutaneous receptive fields ; Spinal cord ; Cat ; Pain
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Examination of cutaneous receptive fields (RFs) of lamina 5 cells in the lumbar spinal cord of decerebrate cats shows them to have three distinct zones with respect to mechanical and electrical stimulation. The mean response rate to both mechanical and electrical stimulation in zone 1 increases steadily up to the highest strengths used; in zone 2, surrounding zone 1 mainly proximally, mild stimuli reduce the mean rate, stronger stimuli increase it; in zone 3, mainly proximal to zone 2, all stimuli reduce the rate. Temporally, zone 1, electric shocks near threshold produce bursts of firing followed by inhibition. With increased stimulus strength, the bursts lengthen to a second or more. In zones 2 and 3, inhibition at all strengths is preceded at higher strengths by bursts of firing. Cold-blocking the spinal cord at lower thoracic levels reversibly increases the ongoing activity of these cells, increases the area of zones 1 and 2, and almost completely suppresses all inhibition. Stimulation of dorsal columns and threshold stimulation of distant dorsal roots inhibits ongoing and induced activity. Barbiturate decreases ongoing activity and the duration of firing produced by cutaneous electrical stimulation but does not decrease inhibition. These results are consistent with a model in which low-threshold fibres are excitatory only over a small central area of the RF of a lamina 5 cell (zone 1), high threshold fibres are excitatory over a larger area (zones 1 and 2), and low threshold fibres are inhibitory over the entire receptive field (zones 1, 2 and 3) with a slower time-course. This inhibition is tonically enhanced by descending influences in the decerebrate cat. It is suggested that the high and low threshold fibres correspond approximately to the small and large diametre fibres whose balance is the basis for the coding of pain in the theory of melzack and wall.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235240
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  • 30
    Digitale Medien
    Digitale Medien
    Die Bedeutung der Vorderhirnkommissuren für die Koordination bilateraler EEG-Muster (1969)
    Springer
    Experimental brain research 7 (1969), S. 195-213 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Corpus callosum ; EEG synchronization ; Homolateral sensory evoked potentials ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Spontaneous EEG-patterns and evoked potentials (EP's) of symmetrical cortical areas were recorded in chronic and acute cats before and after section of the corpus callosum, the commissura anterior and posterior and the massa intermedia. The spontaneous EEG was recorded without and with anesthesia, EP's after electrical stimulation of the fore-paws only during nembutal anesthesia. — No changes in the bilateral coordination of spontaneous and evoked EEG-patterns could be seen after commissurotomy (CT). The bilateral coherence of EEG-waves as revealed by cross-correlation is low already in the normal cats and does not change significantly after CT. The values of cross-correlation coefficients at T = ± 15 msec vary during one EEG-record between -0.25 and +0.25 in the somatosensory, suprasylvian and temporal areas (mean values slightly above 0). In the visual area occasionally positive values between 0.5 and 0.8 were seen, but also here a large variation was found in all animals and the mean values were below 0.1. No consistent phase shift between both sides was observed. EEG-patterns like spindles or arousal, still occurred together in both hemispheres after CT, the variability of their exact beginning or end was the same as in controls. Spontaneous spindles often lasted longer after section of the massa intermedia. Homolateral EP's in the somato-sensory area were still present after CT. Rhythmical afterdischarges could be restricted to the contralateral somato-sensory cortex even before CT.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00239029
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  • 31
    Digitale Medien
    Digitale Medien
    Functional organization of the vestibular afferents to the cerebellar cortex of frog and cat (1969)
    Springer
    Experimental brain research 9 (1969), S. 30-52 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Climbing fibers ; Mossy fibers ; Vestibulo-cerebellar input ; Cat ; Frog ; Golgi cell inhibition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. Field and unitary potentials evoked in the vestibulo-cerebellum of frog and cat following vestibular nerve stimulation were recorded with microelectrodes and correlated with their site of origin in the various layers of the cerebellar cortex. 2. In the frog, primary vestibular fibers project both as mossy and as climbing fibers onto the cerebellar auricular lobe. Secondary vestibulo-cerebellar fibers seem to end exclusively as mossy fibers in the auriculum. As a consequence of this dual projection, extra- and intracellular recordings from Purkinje cells in the auricular lobe show two kinds of responses to vestibular nerve stimulation: a) graded, repetitive firing mediated through mossy fiber-granule cell-parallel fiber pathways, and b) all-or-none burst responses caused by monosynaptic impingement of vestibular climbing fibers on Purkinje cells. 3. The field and unitary potentials evoked in the cat nodulus, flocculus and uvula following vestibular nerve stimulation are shown to be generated by mossy fibers exclusively. Considerable convergence of the two labyrinthine mossy fiber inputs to a given cerebellar area was found. 4. Interaction of contralateral and ipsilateral mossy fiber input at the level of the flocculus suggests that Golgi cell inhibition might operate not only as a simple inhibitory feedback loop, but also as a complex gating operator at the granule layer. 5. No short latency climbing fiber activation of Purkinje cells was observed following VIIIth nerve stimulation. Stimulation of the contralateral inferior olive evoked short latency climbing fiber EPSPs in Purkinje cells of the vestibulo-cerebellum. Suggestions are made as to the possible role of mossy and climbing fiber inputs to this area of the cerebellum.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235450
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  • 32
    Digitale Medien
    Digitale Medien
    Pyramidal control of fusimotor neurons supplying extensor muscles in the cat's forelimb (1969)
    Springer
    Experimental brain research 9 (1969), S. 96-115 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Pyramidal tract ; Fusimotor Neurons ; Forelimb ; Extensor ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effects of cortical stimulation upon dynamic and static sensitivities of the sensory endings in muscle spindles have been analyzed. 63 single afferent fibers from the muscle spindles of the forelimb extensors: M. flexor carpi radialis, M. flexor digitorum communis and M. palmaris longus were isolated in dorsal root filaments in 20 adult cats under chloralose-urethane anesthesia. They were identified by their response to stimulation of the median nerve. 1. Surface anodal repetitive stimulation of the anterior sigmoid gyrus was found to produce an enhancement of static response of single Group II fibers. Effective area was localized in a restricted region which corresponded to the forelimb motor area. The effect was obtained without any concomitant muscle contraction. Similarly, the stimulation increased the resting discharges of the Group Ia fibers from the same muscles. 2. Stimulation of the same area in the cerebral cortex was also found to increase the dynamic sensitivities of primary sensory endings. The increase was revealed by an enhancement of initial burst discharge during relaxation period of a twitch contraction caused by median nerve stimulation. 3. These results indicate that stimulation of the forelimb motor area has a facilitatory effect on both the static and dynamic fusimotor neurons innervating the muscle spindles of the test muscles. 4. The effects were reproduced in pyramidal tract preparations in which the brainstem was cut either at the level of the midbrain except for the cerebral peduncle or at the level of caudal medulla oblongata sparing the pyramid. 5. The threshold for the fusimotor effects was less than 1.3–1.5 times threshold of the pyramidal tract discharge, when the best spot for eliciting the fusimotor response was chosen. These results indicate that the effects of cortical stimulation are mainly mediated by the fast conducting pyramidal tract fibers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238324
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  • 33
    Digitale Medien
    Digitale Medien
    Contrôle de l'activité des fibres fusimotrices dynamiques et statiques par la formation réticulée mésencéphalique chez le chat (1969)
    Springer
    Experimental brain research 9 (1969), S. 307-324 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Muscle spindle ; Gamma motor control ; Mesencephalic reticular formation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Effects of repetitive stimulation of the mesencephalic reticular formation (MRF) on the static discharge and dynamic sensitivity of muscle spindle primary endings (soleus muscle) were studied in cats anaesthetized with Halothane (Fluothane). By progressive increasing the depth of anaesthesia three different fusimotor effects could be observed: 1. A static effect; the static discharge of the primary endings was strongly increased; the response to phasic stretch was decreased or remained unaltered. 2. A dynamic effect; the dynamic sensitivity of the primary endings was powerfully increased while the rate of discharge under static conditions was only slightly augmented. 3. A depressant effect; the static discharge and the dynamic sensitivity of primary endings were decreased. Repeated stimulation elicited successive static and dynamic effects. No specific regions within the MRF could be related to a particular effect.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235241
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  • 34
    Digitale Medien
    Digitale Medien
    Etude fonctionnelle du contrôle de l'activité des fibres fusimotrices dynamiques et statiques par les formations réticulées mésencéphalique, pontique et bulbaire chez le chat (1969)
    Springer
    Experimental brain research 9 (1969), S. 325-345 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Muscle spindle ; Gamma motor control ; Reticular formations ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. During a progressive increase of Fluothane (Halothane) anaesthesia, repetitive stimulation of the mesencephalic retioular formation (MRF) produces several fusimotor effects — static, dynamic or depressant — on primary endings of soleus muscle spindles (Vedel et Mouillac-Baudevin 1969). 2. Transection of the brain immediately rostral to the site of stimulation may increase the dynamic effect but does not alter the static or the depressant effects. 3. A section of the rubrospinal tract does not modify the fusimotor effects elicited by stimulation of the MRF. 4. Transections of the spinal cord have shown that the pathways responsible for the transmission of these effects are mainly situated in the ipsilateral ventral and ventrolateral funiculi which contain the efferent fibers from the pontine reticular formation (PRF), from the bulbar reticular formation (BRF) and from the vestibular nucleus. 5. Contra and ipsilateral PRF stimulation produces the static fusimotor effect; contralateral stimulation from a small anterior region produces the dynamic effect. 6. Stimulation of the lateral part of the ipsilateral BRF elicits the dynamic effect while stimulation of the medial part elicits the static effect.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235242
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  • 35
    Digitale Medien
    Digitale Medien
    Die asynchrone und lokal umschriebene Reizwirkung von Mittelfrequenz-Dauerströmen im Hypothalamus der Katze (1969)
    Springer
    Experimental brain research 9 (1969), S. 164-182 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Emotional behaviour ; Hypothalamus ; Electricalstimulation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. In order to compare the selective value of repetitive cathodal pulses of 8 c.p.s. and of continuous sine-wave alternating currents of 5000 c.p.s. (middle frequency current) when applied to brain tissue, explorations were made in the region of the hypothalamus that had yielded defence and/or flight reactions in earlier experiments. The region was explored by stimulating each point in turn with both current forms. At the same time measurement was made of the impedance of the brain tissue, and the effects produced by altering the time of rise of the middle frequency current on threshold of responses were also studied. The experiments were carried out on unanaesthetized, freely moving cats. 2. Both stimulation types produced affective (“emotional”) responses. The patterns elicited by low frequency cathodal pulse stimulation were often associated with stimulus-bound phasic muscle activity, i.e., flapping of ears, and twitching of whiskers, or, rotation of the head. Such extraneous motor effects were rarely obtained when continuous middle frequency currents were applied, and were tonic in character when present. 3. Mapping of reactive points revealed that the area producing defence or flight following middle frequency stimulation is smaller in size than the field delimited by means of repetitive cathodal pulse stimulation. These results strongly suggest that spread of current can be reduced by using middle frequency current stimulation. This apparently local (and hence highly selective) action is paralleled by a lower impedance of the brain tissue to the rapidly changing polarity of this current. 4. The hissing (and/or growling) associated with the defence pattern showed adaptation to suddenly rising middle frequency currents of 30 secs duration. An increase in threshold of hissing occurred when the time of rise of the current was prolonged. Flight, in contrast, was obtained at the same critical intensity regardless of the time of rise of current. 5. The nature of the stimulatory action of middle frequency current (examined in the peripheral nerve by Wyss) and the advantages presented by this new method of brain stimulation are briefly discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238329
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  • 36
    Digitale Medien
    Digitale Medien
    The lateral cervical nucleus in the cat III. An electron microscopical study after transection of spinal afferents (1969)
    Springer
    Experimental brain research 7 (1969), S. 32-50 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Lateral cervical nucleus ; Spinal lesions ; Ultrastructural investigation ; Degenerating boutons ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of terminal degeneration within the lateral cervical nucleus (LCN) after transection of its spinal afferent fibers 2 days–2 years earlier is described. The degeneration after 2 days was of both the neurofilamentous and dense type. The highest number of degenerating terminals, about 15%, was found after 4–5 days. Then most of the degenerating boutons were of the dense type. The degenerating terminals had synaptic contact with cell bodies and dendrites of LCN-neurons. Removal of the degenerating boutons seemed to be effected by a phagocytic cell present in increased number compared to the normal LCN. In cases with long survival times an increase in the number of astroglial filaments was observed. In an animal where the spinal afferents to the LCN had been cut 2 years earlier a decrease in medium size of the neurons was observed. The amount of dendritic spines was also considerably smaller than normally.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00236106
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  • 37
    Digitale Medien
    Digitale Medien
    Inhibition in the medial geniculate body of the cat (1969)
    Springer
    Experimental brain research 7 (1969), S. 68-83 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Medial geniculate body ; Inhibition ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. Inhibitory activity in the cat medial geniculate body (MG) was examined by stimulating electrically and acoustically the input and output of the MG. 2. A longer and more profound depression of excitability occurs following a click-evoked potential in the MG than in the inferior colliculus (IC) in both anesthetized and unanesthetized states. Recovery is cyclic in the barbiturate MG preparation. 3. Electrical stimulation of the brachium of the inferior colliculus (BIG) evokes a field potential in the MG consisting of clearly distinguishable presynaptic and postsynaptic components. The presynaptic component recovers rapidly, while the postsynaptic component requires 100–200 msec for full recovery. This depression of excitability is localized within the MG since cortical ablation does not alter its occurrence. 4. Stimulation of the BIC mimics the effects of click stimulation on single units. Excitatory, inhibitory and reverberatory responses are evoked by the BIC shock. Suppression of single unit activity correlates with the depression of excitability following a BIC-evoked field response. 5. Cortical stimulation can evoke antidromic and trans-synaptic unit responses in the MG, as well as causing a variety of inhibitory effects and reverberation. In view of the fact that cortical ablation does not impair the recording of these responses to afferent stimuli, it is suggested that the cortical-evoked responses are at least partly mediated by antidromic conduction to MG. 6. Evidence is presented that inhibitory effects of both afferent and cortical stimulation are due to active inhibition of MG unit activity. Speculations are made as to the mechanisms producing inhibition and reverberation in the MG.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00236108
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  • 38
    Digitale Medien
    Digitale Medien
    Electronmicroscopic observations on the structure of the pontine nuclei and the mode of termination of the corticopontine fibres an experimental study in the cat (1969)
    Springer
    Experimental brain research 7 (1969), S. 95-110 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Electron microscopy ; Pontine nuclei ; Experimental neuroanatomy ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The electron microscopical changes occurring in the pontine nuclei following unilateral lesions of the primary sensorimotor cortex have been studied in 7 cats with a survival time from 2–23 days. A description is also given of the fine structure of the pontine regions in receipt of the fibres. These regions are shown in Fig. 1. The study shows that the boutons are practically only in synaptic contact with dendrites. The bouton density on these is only 16%. The boutons are of the en passage and terminal type, with the latter as the most common (Figs. 4a-e). The synaptic vesicles are rounded or elongated. The formaldehyde fixed material had 17.8% boutons with vesicles of the elongated type; the material fixed with a mixture of formaldehyde and glutaraldehyde had only 11.5% of such boutons. The degenerating boutons show the dark type of reaction and the majority of the corticopontine fibres are of the type shown in Figs. 4d and 4e. Astrocytes and microglial cells participate in the removal of degenerating boutons and terminal fibres. Degenerating boutons are present even at the 23 day stage and some have apparently only started to degenerate.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235436
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  • 39
    Digitale Medien
    Digitale Medien
    Eine faktorenanalyse von schwellen subcorticaler reizantworten (1969)
    Springer
    Experimental brain research 8 (1969), S. 79-96 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Evoked potential thresholds ; Factor analysis ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Zur Beschreibung von Korrelationen zwischen zahlreichen elektrophysiologischen Daten aus verschiedenen Hirngebieten wurde eine Faktorenanalyse nach der Hauptachsenmethode gerechnet. Ausgangsmaterial dieser Analyse waren Schwellen subcortical ausgelöster und abgeleiteter Antwortpotentiale auf Einzelreize. Das resultierende Faktorenmuster ermöglicht ein quantitatives Konzept der Schwellendetermination subcorticaler Reizantworten und zugleich ein Modell von Funktionsbeziehungen zwischen einigen Hirnstrukturen. Die Reizungen und Ableitungen erfolgten bei 35 encéphale isolé-Katzen mit Hilfe bipolarer Elektroden in folgenden Arealen: Amygdala, Hippocampus, Septum, N. dorsomedialis Thalami, Hypothalamus posterior und Formatio reticularis mesencephali. Es wurden 435 Korrelationskoeffizienten zwischen den Schwellen von 30 subcorticalen Verbindungen gebildet und zum Zwecke einer Datenreduktion durch eine Matrix von 5 Faktoren reproduziert. 1. Jeder Faktor repräsentierte hohe Schwellenkorrelationen zwischen den efferenten Projektionen jeweils eines Kerngebietes. Demnach nimmt im allgemeinen die Aktivität des Reizortes den größten Einfluß auf die Schwelle eines Antwortpotentials. Diese Hypothese ist durch pharmakologische Untersuchungen belegt worden [27] 2. Kovariationen von Reizantworten mit identischen Ableiteorten ergaben sich ausnahmslos, wenn die Latenzzeiten mehr als 11 msec betrugen. 3. Zusätzlich zeigte die Faktorenmatrix Schwellenkorrelationen zwischen: a) den hypothalamischen Efferenzen und mehreren hippokampalen Afferenzen langer Latenz (positive Korrelationen) b) retikulo-limbischen Verbindungen und „primären” Efferenzen von Amygdala und Hippocampus (positive Korrelationen) c) Antwortpotentialen, die durch Reizung der Formatio reticularis, und solchen, die durch Reizung des N. Amygdalae ausgelöst waren (negative Korrelationen) d) den Efferenzen des N. dorsomedialis Thalami und limbischen Projektionen langer Latenz zur mesencephalen Formatio reticularis (positive Korrelationen) Die Interpretation dieser Zusammenhänge bestätigt und erweitert einige bekannte Modelle von Beziehungen zwischen subcorticalen Kerngebieten. Abschließend wird mit Rücksicht auf die Linearität der mathematischen Methode die Anwendbarkeit der Faktorenanalyse auf Schwellen von Reizantworten diskutiert.
    Notizen: Summary In 35 cats (encéphale isolé) evoked responses were elicited and recorded with bipolar electrodes from the amygdala, hippocampus, septum, dorsomedial thalamic nucleus, posterior hypothalamus, and mesencephalic reticular formation. Correlations between the thresholds of responses in different areas following stimulation of other areas were described by a factor analysis according to the principal axis method. 435 coefficients of correlation were calculated and reproduced by a matrix of 5 factors for the purpose of data reduction. Each factor represented high threshold correlations between the efferent projections of one region, which suggests that the activity of the stimulated site exerts a major influence on the evoked potential threshold. This is supported by pharmacological studies [27, 49]. Covariations of responses recorded in the same nucleus were always found, if the latencies exceeded 11 msec. The factor matrix indicated threshold correlations between: the efferent projections of the hypothalamus and several long latency afferent projections to the hippocampus (positive correlations); reticulo-limbic connections and “primary” efferent connections of the amygdala and hippocampus (positive correlations); evoked potentials following reticular and amygdaloid stimulation (negative correlations); the efferent projections of the dorsomedial thalamic nucleus and long latency limbic projections to the mesencephalic reticular formation (positive correlations). The interpretation of these relationships confirms and extends some well known models of relations between subcortical regions. The applicability of factor analysis to evoked potential thresholds is discussed with regard to the linearity of the mathematical method.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234927
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  • 40
    Digitale Medien
    Digitale Medien
    Interaction of defence and flight reactions produced by simultaneous stimulation at two points in the hypothalamus of the cat (1969)
    Springer
    Experimental brain research 8 (1969), S. 130-149 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Emotional Behaviour ; Hypothalamus ; Electrical stimulation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. The results presented in the present paper are an extension of preceding work devoted to exploration of the hypothalamic defence and flight fields using coaxial electrodes with small cathode. In 33 cats simultaneous stimulation was applied to two points which upon single stimulation had yielded defence, flight, or defence and flight respectively. Results were compared with those produced at either point alone. In 2 cats combined stimulation of a defence and a flight point was carried out with a stuffed cat present. 2. The latencies and rates of the vocal effects associated with defence (growling and hissing), and the latencies of flight (jump from the table) were measured. 3. Simultaneous stimulation of two points which had yielded defence, or of two points which had yielded flight resulted in facilitation (spatial summation) of the effects evoked: a more complete defence response associated with decrease of the latencies and increase in the rates of the vocal effects; decrease of flight latencies and increase of flight impetuosity. 4. Simultaneous stimulation of a defence point which had yielded growling at lower threshold than hissing, and of a point which had yielded flight resulted in facilitation of hissing. Growling and flight were often suppressed; when they occurred, latencies were lengthened and growling rates were increased somewhat. 5. Stimulation of a defence point with a dummy present produces striking (fending off). Simultaneous stimulation of a flight point resulted in facilitation of both hissing and striking. 6. It is concluded that the complex patterns obtained when defence is combined with flight are the result of facilitatory and inhibitory interaction between the elements of the individual patterns.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234535
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  • 41
    Digitale Medien
    Digitale Medien
    Räumliche summation und hemmungsvorgänge im receptiven feldzentrum von retina-neuronen der katze (1969)
    Springer
    Experimental brain research 8 (1969), S. 37-52 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Retinal Ganglion Cells ; Spatial Summation ; Center Inhibition ; Dynamic Organisation of Receptive Fields ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. An retinalen Ganglienzellen der Katze wurde die räumliche Summation im receptiven Feldzentrum (KFZ) bei Dunkeladaptation und Helladaptation durch mittelpunktzentrierte Lichtreize verschiedener Flächengrößen untersucht. Als Kriterium dienten die Entladungsraten der ersten 200 und 500 msec nach Licht-an oder Licht-aus. Das Summationsverhalten wurde sowohl für Einzelneurone als auch gruppenstatistisch für die beiden Neuronen-Systeme B (on-Zentrum) und D (off-Zentrum) untersucht. 2. Die räumliche Summation ist auf den inneren Bereich des RFZ beschränkt: bei on-Zentrum-Neuronen steigt die Entladungsrate nur bis zu Reizflächen, die etwa 1/5 der Fläche des RFZ belichten, bei off-Zentrum-Neuronen bis zu Reizflachen von ca. 1/10 des RFZ. Bei Variation der Reizfläche zwischen 20 und 100% der Fläche des RFZ bleibt das Entladungsniveau konstant (asymptotischer Verlauf der Summationskurve). 3. Die Begrenzung der räumlichen Summation auf einen kleinen Bereich des RFZ beweist eine bereits im Feldzentrum wirksame Hemmung. Diese Zentrum-Inhibition begrenzt die Erregungssummation im RFZ bei zunehmender Flächengröße des Lichtreizes. 4. On- und off-Zentrum-Neurone unterscheiden sich in beiden Adaptationszuständen in der Höhe des Entladungsniveaus. Die Entladungsraten der on-Zentrum-Neurone nach Licht-an übertreffen um ein Mehrfaches die Entladungsraten der off-Zentrum-Neurone nach Licht-aus. Die Unterschiede sind gruppenstatistisch hoch signifikant. Die interneuronale Variabilität der Entladungsraten ist bei den onZentrum Neuronen erheblich geringer als bei den off-Zentrum-Neuronen. 5. Dunkel -und Helladaptation führt zu signifikantem Unterschied der Entladungsraten: bei Helladaptation liegt die Impulsrate beider Neuronentypen höher als bei Dunkeladaptation und der Summationsbereich ist um 5–10% größer. 6. Für die mathematische Beschreibung der Summationsverläufe ist die Hyperbel besser geeignet als die logarithmische und Potenzfunktion. Logarithmus- und Potenzfunktionen beschreiben den konstanten asymptotischen Teil der Summationskurven ungenügend und eigenen sich nur für den Kurventeil im innersten Summationsbereich. Die Bedeutung der Befunde für eine dynamische Interpretation der visuellen Feldorganisation und mögliche Beziehungen zur lateralen Umfeldhemmung werden diskutiert.
    Notizen: Summary 1. Spatial summation of suprathreshold light stimuli within receptive field centers (RFZ) of retinal ganglion cells was investigated during dark and light adaptation in cats. The mean discharge rates for 200 and 500 msec following light on or off were the computed response criteria. The summation effects were analyzed for single neurones and statistically for grouped neuron populations of the two neuronal subsystems B (on-center-neurones) and D (off-center-neurones). 2. Spatial summation is restricted to a small part of the RFZ. On-centerneurones increase their on-discharge rates with increasing spot sizes, only if the stimulus illuminates less than 1/5 of the RFZ. The summating area of the off-centerneurones is smaller (about 1/10 of the RFZ). 3. The limitation of spatial summation to a small part of the RFZ indicates the existance of inhibition within the RFZ. This center-inhibition sets a constant limit for excitation summation in the RFZ. 4. The mean neuronal response rates for the 2 subsystems show significant differences: The on-discharges of the on-center-neurones exceed the off-discharges of the off-center-neurones by a factor of 3–5. These highly significant differences occur at both adaptation levels and are not due to different spontaneous activity. Interneuronal response variability of the off-center-neurones was twice as large as that of the on-center-neurones. 5. Change from dark to light adaptation had only a small but significant influence on summation properties. The poststimulus discharge rates were higher during light adaptation and the summating area was slightly larger (about 5–10%). 6. A comparative curve fitting procedure for three suitable mathematical functions revealed that the hyperbola describes the neuronal summation curves better than a logarithmic or power function. The latter do not fit the constant asymptotic part of the curve. The significance of the results for a dynamic interpretation of the organisation of visual receptive fields is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234924
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  • 42
    Digitale Medien
    Digitale Medien
    Räumliche summation im receptiven feldzentrum von neuronen des geniculatum laterale der katze (1969)
    Springer
    Experimental brain research 8 (1969), S. 53-65 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Lateral geniculate body ; Spatial summation ; Off-center-characteristics ; Geniculate transfer ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. Die räumliche Summation im receptiven Feldzentrum von Neuronen des Corpus geniculatum laterale (CG-L) wird beschrieben und mit entsprechenden Untersuchungen an retinalen Ganglienzellen verglichen. Neben größerer interneuronaler Variabilität ergeben sich ausgeprägtere Unterschiede der Summationseigenschaften der on-und off-Zentrum-Neurone. Der effektive Summationsbereich von etwa 1/5 der Fläche des RFZ ist in Retina und CGL etwa gleich. 2. Die on-Zentrum-Neurone des CGL zeigen in beiden Adaptationszuständen einen ähnlichen Summationsverlauf wie in der Retina. Das Entladungsnieau ist im CGL jedoch erheblich geringer und nicht durch Unterschiede in der Spontanaktivität zu erklären. 3. Die Mehrzahl der off-Zentrum-Neurone des CGL zeigt bei DA inverse Summationsverläufe wie in der Retina: durchgehende Verminderung der Entladungsrate der off-Antworten bei Vergrößerung der Reizfläche im RFZ. Eine kleine Gruppe zeigt einen parabelförmigen Summationsverlauf mit Entladungszunahme bis zu Reizflächen von 10–30% der Fläche des RFZ und darauffolgender Entladungsminderung. Bei Helladaptation zeigen fast alle off-Zentrum-Neurone diesen Parabelverlauf. Das durchschnittliche Entladungsniveau ist von dem retinaler offZentrum-Neurone nicht signifikant verschieden. 4. Die interneuronale Variabilität der Summationsvorgänge im RFZ von CGLNeuronen ist gegenüber den retinalen Ganglienzellen deutlich größer. Dies gilt insbesondere für die off-Zentrum-Neurone. Das Summationsverhalten von CGLNeuronen läßt sich daher nicht wie in der Retina durch einen Funktionstyp beschreiben. 5. Die Befunde sprechen für eine Transformation des retinalen Eingangs der off-Zentrum-Neurone im CGL, während die on-Zentrum-Neurone außer der bekannten Frequenzuntersetzung keine wesentliche Umformung erkennen lassen.
    Notizen: Summary 1. Spatial summation in the receptive field center of neurones of the lateral geniculate body (CGL) is limited by inhibition to a small part of field center. Variations of stimulus size are only effective if the stimulus is smaller than about 1/5 of the area of receptive field center. Thus, the active summating area of the field center in the CGL corresponds to that of the retina. Geniculate neurones, however, show less homogeneous responses and the summation properties of the two neuronal subsystems (on-center-and off-center-cells), show greater differences than in the retina. 2. The form of summation curves for the on-center-neurones of the CGL is similar to those of the retina at both adaptation levels. However, the average responses rates in the CGL are considerably lower. This is not due to differences of spontaneous activity. 3. The summation characteristics of off-responses of off-center-neurones of the CGL are quite different from those in the retina. In dark adaptation the majority of CGL neurones respond with decreasing discharge rates to increasing spot-sizes within the field center. A small number show an initial increase of discharge rates up to stimulus sizes of about 1/10 of the receptive field center before a decrease occurs. This parabolic summation type is typical for most off-center-neurones in light adaptation. The mean discharge levels are the same as those of the retinal offcenter-neurones. 4. The higher interneuronal variability of summation curves especially of the off-center-neurones of the CGL indicates a more complex determination of the discharge properties of CGL neurones. This functional differentiation of single neurones is congruent with the more complex structural and synaptic organisation in CGL. 5. With respect to spatial summation, the results indicate a transformation of the retinal input of the off-center-neurones at the geniculate level, whereas the oncenter-neurones are nearly unchanged.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234925
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  • 43
    Digitale Medien
    Digitale Medien
    Langfristige Verträglichkeitsprüfung mit Benperidol an der Katze (1969)
    Springer
    Psychopharmacology 14 (1969), S. 164-166 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Benperidolum ; Cat ; Extrapyramidal Side Effect ; EEG ; Toxicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Daily doses of 1–10 mg Benperidol were given perorally to cats during 26 months. The general behaviour and the EEG were unchanged during the treatment, in particular no signs of dyskinesia were observed. After discontinuation of the administration, the behaviour and the EEG of the animals stayed normal. Thus no lasting and irreversible side effects could be observed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00403690
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  • 44
    Digitale Medien
    Digitale Medien
    Effects of LSD on the spontaneous and evoked activity of retinal and geniculate ganglion cells (1969)
    Springer
    Psychopharmacology 15 (1969), S. 382-391 
    Details
    ISSN: 1432-2072
    Schlagwort(e): LSD ; Retina ; LGN ; Single Unit Activity ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effect of LSD 25 (i. v. injection) on the spontaneous and evoked activity of the visual system was investigated in cats. 50 γ/kg did not change significantly the ERG and the visual cortical evoked potential. The spontaneous discharge rate of 14 out of 21 retinal ganglion cells showed an increase which reached its maximum within 20–30 min and which could still be present 1 hour following the injection. One third of the retinal units showed a slight depression of their spontaneous dischaRge rate with about the same time course. Single units of the LGN showed about the same behaviour. The response to light stimulation was slightly increased in some units and light induced inhibition was slightly shortened. The possible mechanism of the LSD-effect on retinal ganglion cell activity is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00403713
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  • 45
    Digitale Medien
    Digitale Medien
    Responses of neurones in cat's abducens nuclei to horizontal angular acceleration (1969)
    Springer
    Pflügers Archiv 309 (1969), S. 285-309 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Labyrinthine Stimulation ; Types of Abducens Neurones ; Frequency Analysis ; Cat ; Labyrinthreizung ; Abducensneurone ; Frequenzanalyse ; Katze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Single cell activity was recorded extracellularly from neurones in cat's abducens nuclei in unanesthetized, decerebrate preparations. Two types of neurones were found. i) The motoneurones (type IIA) increased their firing linearly or exponentially to contralateral constant angular accelerations and decreased firing to ipsilateral rotation. The increased frequency was maintained at a constant level without any sign of adaptation. This constant level of maximum frequency was proportional to the logarithm of the acceleration applied. No significant differences of the frequency responses of tonic and silent motoneurones were found. The conduction velocities of the axons of spontaneously firing type IIA cells were slower than in silent neurones. Electrical stimulation of the contralateral VIIIth nerve led to activation of the type IIA cells; stimulation of the ipsilateral nerve resulted in inhibition of both spontaneous discharge and antidromic invasion of the motoneurones. ii) The type IA units increased their firing rate to ipsilateral rotation and ceased to discharge in response to contralateral rotation. They never were excited antidromically by stimulation of the VIth nerve. However, they were excited by stimulation of the ipsilateral VIIIth nerve. Their possible functional role in the vestibulo-ocular system was discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00587754
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  • 46
    Digitale Medien
    Digitale Medien
    Die Rolle „spezifischer” und unspezifischer Afferenzen für den Antrieb der Atmung, untersucht durch Reizung und Blockade von Afferenzen an der decerebrierten Katze (1969)
    Springer
    Pflügers Archiv 312 (1969), S. 189-205 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Cat ; Decerebration ; Afferents to Respiratory Centers ; Medulla Oblongata ; Reticular Formation ; Katze ; Decerebrierung ; Afferenzen zu Atemzentren ; Medulla oblongata ; Formatio reticularis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung An 11 intercolliculär decerebrierten Katzen wurde geziegt, daß Kälteblockade eines eng umschriebenen Feldes auf der ventralen Oberfläche der Medulla oblongata, wie früher für anaesthesierte Tiere beschrieben, zu Atemstillstand führt, wenn die kontralaterale Stelle auf der Medulla oblongata, die Sinusnerven und die Vagi ausgeschaltet sind. Zu Atemstillstand kam es auch, wenn statt der Kälteblockade 2% Novocain durch lokale Superfusion bei gleichzeitiger Gegenspülung der Umgebung mit künstlichem Liquor angewandt wurde, oder wenn ein mit 1% Novocain getränkter Tupfer lokal aufgelegt wurde. Außerdem führte Kälteblockade zu Atemstillstand, wenn durch kontinuierliche auch während der Kälteblockade anhaltende elektrische Reizung eines N. femoralis oder hinterer Lumbalwurzeln an decerebrierten Katzen oder des Hypothalamus an einer anaesthesierten Katze Steigerungen der Ventilation ausgelöst worden waren. Elektrische Reizung eines Sinusnerven führte zu Atemsteigerungen. Bei Sinusnervenreizung während eines durch Kälteblockade ausgelösten Atemstillstands kam es zu rhythmischer Atmung. Aus diesen Untersuchungen wird geschlossen, daß mit der Ausschaltung der beschriebenen Felder auf der ventralen Oberfläche der Medulla oblongata am sonst desafferentierten Tier die Gesamtheit der für die zentrale CO2-Empfindlichkeit verantwortlichen Strukturen erfaßt ist, daß nach Ausschaltung der zentralen und der peripheren Chemosensibilität eine unspezifische Aktivierung der Atmungszentren unwirksam ist und daß die Atmungszentren zur Ausbildung einer rhythmischen Atmung von spezifischen Antrieben abhängig sind.
    Notizen: Summary It was shown in 11 decerebrated cats, that cooling of a small and well defined area on the ventral surface of the medulla will cause respiratory arrest if the contralateral area of the medulla, the vagi and sinus nerves are eliminated. This confirms earlier observations obtained in anesthetized cats. Apnea was also produced by local superfusion of 2% procain with simultaneous flushing of the immediate surrounding area with mock spinal fluid. Local application of a small sponge soaked with 1% procain had the same effect. Electrical stimulation of femoral nerves or posterior roots which results in hyperventilation on the decerebrated cat failed to show any effect during periods of cold blockade. There was no respiratory response to direct stimulation of the hypothalamus in an anesthetized cat during cooling. Electrical stimulation of one sinus nerve caused an increase of ventilation. Sinus nerve stimulation during apnea induced by cold blockade resulted in rhythmical respiration. It is concluded from these experiments: Blocking of the area under discussion on the ventral surface of the medulla, inhibits all structures responsible for the central CO2-sensitivity in the deafferentiated animal. There was no response to non-specific stimuli of the respiratory center after elimination of central and peripheral chemosensitivity. The respiratory centers apparently depend on specific stimuli to support rhythmical respiration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00586928
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  • 47
    Digitale Medien
    Digitale Medien
    Defence, attack, and flight elicited by electrical stimulation of the hypothalamus of the cat (1969)
    Springer
    Experimental brain research 8 (1969), S. 113-129 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Emotional behaviour ; Hypothalamus ; Electrical stimulation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1. Affective behaviour patterns produced by electrical stimulation of the hypothalamus were studied in unanaesthetized, freely-moving cats. Bipolar stimulation with coaxial electrodes and small cathode was used to elicit defence, attack or flight. The development of these responses was studied by varying stimulation strength. In some experiments a stuffed animal was introduced in order to study the reactions of the cat to changes in the environment during stimulation. 2. The following responses were evoked at threshold intensity: (i) growling reaction; (ii) hissing reaction; (iii) two types of flight — type a preceded by hastily looking to and fro as if in search of an exit, type b preceded by inspection of surroundings, in most cases associated with sniffing. 3. Increasing stimulation 1.5 times threshold often yielded combined patterns. At points yielding the growling reaction a defence response in which growls alternated with hisses was obtained. The points yielding flight type a sometimes yielded hissing followed by flight. Increasing stimulation at hissing points yielded either a defence reaction or the combined effect hissing-flight. 4. The growling reactions were obtained from the tuber region. The hissing responses were obtained from points above the tuber. The flight reactions, type a, were produced from the intermediate zone extending from the level of the preoptic area to the mamillary bodies and type b from the caudo-lateral hypothalamus. 5. The reactions of the cats to a dummy during stimulation varied depending on the type of response which had been evoked in the absence of the dummy. The defence reaction was converted into threatening and striking of the dummy, the combined effects into threatening, striking or biting, culminating in sudden flight. The dummy was ignored during stimulation of points yielding flight type a, but examined by sniffing during stimulation of points yielding flight type b.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234534
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  • 48
    Digitale Medien
    Digitale Medien
    Evidence for mediated transport of chloride in cat cerebral cortex in vitro (1969)
    Springer
    Experimental brain research 8 (1969), S. 219-231 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cerebral cortex in vitro ; Chloride transport ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The kinetics of the uptake of chloride by slices of cat cerebral cortex incubated in vitro have been studied for a wide range of concentrations of chloride and potassium in the incubation media. 1. In studies with 36Cl at a constant concentration of external K+, the rate of entry of chloride into slices of cat cerebral cortex (after equilibration with the fluid of the extracellular space) followed Michaelis-Menten kinetics with Vmax=7.7 μmoles/g/min and Km=245 mM. The kinetic data so described differ significantly from a curve describing simple diffusion (P 〈 0.02). 2. A clear dependence on concentration of K+ in the incubation medium was demonstrated. When external chloride was held constant at 6.8 mM and concentrations of potassium were varied over a range of 27–100 mM, the apparent rate of entry of chloride followed Michaelis-Menten kinetics with Vmax=0.191 μmoles/ g/min and Km=30.3 mM. 3. Under similar equilibrium conditions, the rate of influx of chloride was not statistically different from the rate of efflux, and the value for extracellular space (355 μl/g) derived by extrapolation from efflux data was of an identical order of magnitude to the value (352 μl/g) obtained from influx data. These values are essentially identical to those previously determined for chloride space of cat cerebral cortex in vivo (Bourke, Greenberg and Tower 1965). 4. The total, membrane-delimited content of chloride in cerebral cortex, as defined in these studies in vitro, was a function of the concentration of K+ in the incubation medium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234250
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  • 49
    Digitale Medien
    Digitale Medien
    Studies of the development and subsequent reduction of swelling of mammalian cerebral cortex under isosmotic conditions in vitro (1969)
    Springer
    Experimental brain research 8 (1969), S. 232-248 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cerebral cortex in vitro ; Edema ; Fluid compartmentation ; Chloride transport ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ionic parameters of incubation media which foster both the development and subsequent reduction of swelling of slices of cerebral cortex under isosmotic conditions of incubation in vitro are described. A linear relationship between increasing chloride concentrations in incubation media and progressive swelling of tissue slices (under conditions of constant temperature and K+ concentrations and isotonicity of incubation media) is demonstrated. Subsequent reduction of chloride concentration in incubation media together with reciprocal replacement by isethionate is associated with significant and characteristic reduction in the volume of tissue swelling when all other conditions of incubation, including isotonicity of the media, are kept constant. The ionic composition of the fluid of swelling under different conditions of incubation is derived together with the ionic composition and expected transmembrane potentials of the neuronal compartment of cerebral cortex in vitro. Mechanisms involved in the development and subsequent reduction of swelling of cerebral cortex in vitro are discussed, and proposals for possible clinical applications are suggested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00234251
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  • 50
    Digitale Medien
    Digitale Medien
    Verbesserung der Resorption von Helveticosid und Helveticosol durch Substitution der Hydroxylwasserstoffe an der Digitoxose (1969)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 262 (1969), S. 73-86 
    Details
    ISSN: 1432-1912
    Schlagwort(e): Strophanthidine Derivatives ; Toxicity ; Absorption ; Guinea-Pig ; Cat ; Strophanthidinderivate ; Toxicität ; Resorption ; Meerschweinchen ; Katze
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Es wurde die Wirksamkeit verschiedener Ester und Äther von Helveticosid und Helveticosol bei i.v. und intraduodenaler Zufuhr an Katzen und Meerschweinchen geprüft. 1. Bei i.v. Dauerinfusion waren Helveticosol und seine Derivate bei Meerschweinchen etwa doppelt so wirksam wie die analogen Helveticosidverbindungen. Bei der Katze bestand kein Unterschied. Die Monomethyläther Cymarin und Cymarol waren gleich oder sogar stärker wirksam, alle übrigen Derivate deutlich schwächer als die Ausgangssubstanzen. 2. Die tödlichen Dosen bei intraduodenaler Injektion lagen beim Meerschweinchen für einige Substanzen in gleicher Größenordnung oder niedriger als die Titer bei i.v. Infusion. Diese hohe enterale Wirksamkeit kann bei Helveticosid und seinen Derivaten durch eine Reduktion zu dem wirksameren Helveticosol, bei Estern außerdem durch eine Hydrolyse zu wirksameren Glykosiden vorgetäuscht werden. 3. Bei intraduodenaler Infusion an Katzen waren alle geprüften Ester und Äther wirksamer als Helveticosid und Helveticosol. Die aus dem Verhältnis der toxischen Dosen bei i.v. und intraduodenaler Infusion berechnete enterale Wirksamkeit lag zwischen 20 und 50%. 4. Unterschiede in der Dauer der intraduodenalen Infusion bei Katzen lassen sich berücksichtigen, wenn man von der theoretischen Annahme einer exponentiellen und vollständigen Resorption ausgeht und die Halbwertszeit für die Resorption berechnet. Die minimale Resorptionsgeschwindigkeit lag bei einigen Derivaten in gleicher Größenordnung wie bei Digoxin und Digitoxin. Es wird auf den Unterschied zwischen der auf Grund der pharmakologischen Wirkung bestimmten relativen enteralen Wirksamkeit und der Resorptionsquote hingewiesen. Letztere ist für die Verläßlichkeit der therapeutischen Wirkung eines Glykosids bei oraler Gabe maßgebend.
    Notizen: Summary The efficacy of several esters and ethers of Helveticosid and Helveticosol was assayed by intravenous and intraduodenal administration to cats and guinea-pigs. 1. In guinea-pigs, Helveticosol and its derivatives were approximately twice as active on intravenous infusion as the analogous derivatives of Helveticosid; in cats there was no significant difference. The monomethylethers Cymarin and Cymarol were equally or slightly more potent, all other derivatives were weaker than the original compound. 2. In guinea-pigs the lethal doses of some compounds on intraduodenal injection were equal to or even lower than those on intravenous infusion. This may partly be accounted for by a reduction of Helveticosid and its derivatives to the more potent Helveticosol analogues, partly by a hydrolysis of the esters, yielding compounds of higher activity. 3. On intraduodenal infusion in cats, all the investigated esters and ethers were more active than Helveticosid and Helveticosol. The relative enteral activity calculated from the ratio of the toxic doses on intravenous and intraduodenal infusion varied between 20 and 50%. 4. Due to a delayed absorption from the gastrointestinal tract, the toxic dose falls with a reduced speed of intraduodenal infusion. Assuming an exponential and complete absorption, the half time of absorption was calculated. For some of the compounds investigated, the speed of absorption was comparable to that of Digoxin and Digitoxin. The difference between the relative enteral activities determined by comparing equiactive doses on enteral and parenteral administration and the percentages of the glycosides which are absorbed from the gastrointestinal tract is pointed out. The latter is of prime importance for obtaining reproducible effects after enteral administration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00536819
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  • 51
    Digitale Medien
    Digitale Medien
    Morphologische Untersuchungen an der Glandula bulbourethralis der Katze (1969)
    Springer
    Cell & tissue research 101 (1969), S. 607-620 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Glandula bulbourethralis ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Das Parenchym der Glandula bulbourethralis der Katze besteht aus weitlumigen, gebuchteten intraglandulären Gängen, in welche kurze, englumige, zumeist unverzweigte Tubuli einmünden. Der Drüse fehlt eine äußere Organkapsel, so daß ihre peripheren Tubuli stellenweise direkt zwischen den Fasern des quergestreiften M. bulboglandularis liegen. Die Drüsentubuli und die Buchten der intraglandulären Gänge sind mit einem einschichtigen Zylinderepithel ausgekleidet, auf den Gangfalten ist das Epithel abschnittsweise mehrreihig, Die sezernierende Epitheloberfläche ist durch die Ausbildung von interzellulären Sekretkapillaren vergrößert. Breite Zwischenzellspalten (Durchmesser etwa 1,5μ), in welche schlanke interdigitierende Cytoplasmafortsätze hineinragen, erstrecken sich von der Basalmembran bis kurz unter das Tubulusbzw. Ganglumen. Die lumenseitigen Zellgrenzen tragen einige stummelförmige Mikrovilli und besitzen zerklüftete Außenkonturen, die durch glykogenreiche Cytoplasmaprojektionen bedingt sind. Alle Epithelzellen sind reich an Mitochondrien. Die supranuklearen Abschnitte der meisten Gang- und Tubuluszellen enthalten Sekretgranula, welche im Elektronenmikroskop unterschiedliche optische Dichten aufweisen können. Die Granula enthalten ein PAS-positives, neuraminsäurehaltiges epitheliales Muzin, das in einzelnen Sekretkörnchen auch eine histochemische Reaktion auf Sulfatgruppen gibt. Alle Epithelzellen reagieren sehr stark auf unspezifische Esterase und stark auf β-D-Glucuronidase, β-D-Glactosidase sowie die Enzyme des Citronensäurezyklus, der Glykolyse und der Atmungskette (NAD-ICDH, SDH, ALD, LDH, ADH, GDH, NADH-T-Red, Cyt-Ox).
    Notizen: Summary The bulbourethral glands of sexually mature male cats are studied with the light and electron microscope. The parenchyma consists of spacious, sinus-like intraglandular ducts and short, narrow, mostly unbranched tubular endpieces. The gland has no complete connective tissue capsule, consequently some of the peripheral tubules are situated directly in between the fibers of the surrounding bulboglandularis muscle. The endpieces and the sinus of the intraglandular ducts are lined by a simple columnar epithelium, whereas the folds of the ducts are generally covered by a low pseudostratified epithelium. The secretory surface of the cells is increased by intercellular canaliculi which communicate with the gland lumen. These canaliculi are identified on the light microscopic level by their strong 5′-nucleotidase activity. Furthermore widened intercellular spaces (approximately 1,5 μ in diameter) filled with slender, interdigitating cytoplasmic processes extend from the basal lamina to the apical junctional complexes. The luminal cell pole exhibits some short microvilli and forms irregularly shaped, glycogen containing protrusions. Within the cytoplasm of the gland cells numerous spherical mitochondria, some dense bodies, a typical Golgi apparatus, free ribosomes and a poorly developed endoplasmic reticulum are to be observed. Secretory granules which can be grouped into three types on the basis of their electron density occur in the supranuclear regions of most of the cells. According to histochemical tests all granules contain a periodate reactive sialomucin and some of them also sulfate groups. The glandular parenchyma is site of an exceptionally strong unspecific esterase activity and is rich in β-D-glucuronidase, β-D-glactosidase, aldolase, α-glycerophosphate dehydrogenase, lactate dehydrogenase, alcohol dehydrogenase, NAD-dependent isocitrate dehydrogenase, succinate dehydrogenase and cytochrome oxydase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00335273
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