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  • 1
    ISSN: 1432-041X
    Keywords: Cell migration ; CNS ; Glia ; Moth Postembryonic development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Migration of neurons over long distances occurs during the development of the adult central nervous system of the sphinx moth Manduca sexta, and the turnip moth Agrotis segetum. From each of the suboesophageal and three thoracic ganglia, bilaterally-paired clusters of immature neurons and associated glial cells migrate posteriorly along the interganglionic connectives, to enter the next posterior ganglion. The first sign of migration is observed at the onset of metamorphosis, when posterio-lateral cell clusters gradually separate from the cortex of neuronal cell bodies and enter the connectives. Cell clusters migrate posteriorly along the connective to reach the next ganglion over the first three days (approximately 15%) of pupal development. During migration, each cell cluster is completely enveloped by a single giant glial cell spanning the entire length of the connective between two adjacent ganglia. Intracellular cobalt staining reveals that each migrating neuron has an ovoid cell body and an extremely long leading process which extends as far as the next posterior ganglion; this is not a common morphology for migrating neurons that have been described in vertebrates. Once the cells arrive at the anterior cortex of the next ganglion, they rapidly intermingle with the surrounding neurons and so we were unable to determine the fate of the migrating neurons at their final location.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract A laser micro-beam unit was used to reproducibly and selectively eliminate the large horizontal and vertical motion sensitive neurons (H- and V-cells) of the lobula plate on one side of the brain of house fliesMusca domestica. This was achieved by ablating the precursors of these cells deep in the larval brain without damaging other cells in the brain or other tissues. The individually reared flies were tested for their behaviour. Three tests were performed: (i) visual fixation of a single stripe, (ii) the optomotor turning and thrust response to a stripe moving clockwise and counterclockwise around the fly, (iii) the monocular turning response to a moving grating. The responses to a moving single object were normal on both sides, the control side and the one lacking the H- and V-cells. However, the responses to a moving grating were reduced on the side lacking H- and V-cells for progressive (front to back) and regressive (back to front) motion. From this we conclude that the response to single objects is controlled mainly by cells other than the H- and V-cells. We also suggest two separate pathways for the processing of single object motion and wide field pattern motion respectively (Fig. 8). Furthermore, the H- and V-cells might function as visual stabilizers and background motion processors.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Two neurohemal organs of the cockroach Leucophaea maderae, the corpora cardiaca and the lateral heart nerve are known to contain leucokinin immunoreactive material. We examined the corpora cardiaca and the lateral heart nerve to establish whether these neurohemal organs store all 8 known leucokinin isoforms or if the leucokinins have a differential distribution. Extracts of corpora cardiaca and abdominal hearts with attached lateral heart nerve were separated on reversed phase high performance liquid chromatography (rpHPLC), then tested for leucokinin immunoreactivity by a radioimmunoassay (RIA) able to detect all 8 leucokinin isoforms. Extracts from brain and optic lobes were also separated and assayed in the RIA. Synthetic leucokinin 1–8 were subjected to rpHPLC and their different retention times established by RIA for reference. Leucokinin immunoreactive material originating from the corpora cardiaca and lateral heart nerves eluted in fractions corresponding to those of the synthetic leucokinin 1–8. In this study we have thus demonstrated that probably all 8 leucokinin isoforms are stored in the corpora cardiaca and the lateral heart nerve. These observations suggest that all 8 leucokinins are likely to be released as neurohormones into the circulation.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Galanin message-associated peptide (GMAP) is a flanking peptide in mammalian preprogalanin located C-terminally of galanin (GAL). GMAP-like immunoreactive (LI) material in the brain of the blowfly Phormia terraenovae was analysed by radioimmunoassay combined with reversed-phase high-performance liquid chromatography and immunocytochemistry and compared to GAL-LI material. A sensitive radioimmunoassay, developed against a species-conserved portion of mammalian GMAP (synthetic porcine GMAP(19–41)amide), was applied to serially diluted blowfly head extracts. High-performance liquid chromatography combined with radioimmunoassay showed that the GMAP-LI material eluted as several different components with one major component coeluting with the synthetic GMAP fragment. One GMAP-LI peak co-eluted with a GAL-LI component of the extract. By immunocytochemistry it was shown that a distinct set of GMAP-LI neurons and neurosecretory cells is present in the blowfly brain and thoracico-abdominal ganglion. About 150 GMAP-LI cell bodies were found in the brain, distributed in the protocerebrum, tritocerebrum and suboesophageal ganglion. Several hundred GMAP-LI cell bodies were detected in the medulla of the optic lobe. In the fused thoracico-abdominal ganglion there are about 70 GMAP-LI cell bodies distributed in a segmental fashion. Several of the GMAP-LI neurons also contain GAL-LI material whereas some do not. In addition, there are GAL-LI neurons that do not react with the GMAP antiserum. Some of the GMAP-LI interneurons and neurosecretory cells could be traced in detail enabling a resolution of putative sites of action of the peptide.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 131 (1979), S. 205-216 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Effects of light and dark adaptation on the photoreceptor membranes of the rock crabGrapsus have been quantitatively studied using light and electron microscopy to document changes in rhabdom size and their fine structural basis. Some comparative data were also obtained for the ghost crabOcypode. Animals in the laboratory were maintained on a daily light (L)-dark (D)cycle 12L∶12D. Periods of adaptation ranged from 3–28 h (Table 1) and light adaptation was effected at one moderate intensity equal to the light period in the daily sequence. 2. Massive rapid reversible changes in rhabdom size (Fig. 1) comprising mainly diameter modulation (Figs. 2, 3) and some alteration in length, normally resulted in maximum increases in receptor organelle volume of about 20× between a thinner, shorter fully light adapted condition (2×290 μm) to the fully dark adapted state (7.9× 336 μm). 3. Rhabdom growth during dark adaptation (Table 2) was due mainly (Fig. 8) to microvillus elongation (+154%) as well as substantial increase (+117%) in the number of microvilli present in cross sections (Figs. 2, 3, 10); microvillus diameter (Figs. 4, 5, 9) also increased (+14%) but accounts for only a minor part of the overall change commensurate with observed differences in rhabdom length (+16%). Calculation shows that from fully light adapted to fully dark adapted state the area of photoreceptor membrane increased nearly 20× in a few hours. 4. Although duration of adaptation affected its amplitude, six hours of either light or darkness evoked the maximum changes documented; shorter and longer periods had less effect (Figs. 6, 7). 5. Time of day had a strong periodic influence on the amplitude of membrane adaptation produced by a given exposure to dark or light. Thus maximum dark adaptation occurred with 6 h of darkness terminating at midnight and maximum light adaptation with 6 h of light ending at noon of the diurnal light cycle (Fig. 11). 6. Direct effects of light and dark on synthesis and degradation of photoreceptor membrane must therefore be superimposed on indirect or direct cyclic neuroendocrine control presumably coupled to an entrained circadian oscillator.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 293 (1981), S. 398-399 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] At least 12 different classes of directionally motion-sensitive large cell have been identified anatomically and electro-physiologically in the posterior lobula plate of the optic lobes3'9. In the flies Calliphora and Phaenicia, some of these cells respond to horizontal motion2 4, others to ...
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  • 7
    ISSN: 1432-0878
    Keywords: Perisympathetic organ ; Metamorphosis ; Nervous system, insect ; Leucokinin I ; Neuropeptide immunocytochemistry ; Agrotis segetum (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the abdominal ganglia of the turnip moth Agrotis segetum, an antibody against the cockroach neuropeptide leucokinin I recognizes neurons with varicose fibers and terminals innervating the perisympathetic neurohemal organs. In the larva, the abdominal perisympathetic organs consist of a segmental series of discrete neurohemal swellings on the dorsal unpaired nerve and the transverse nerves originating at its bifurcation. These neurohemal structures are innervated by varicose terminals of leucokinin I-immunoreactive (LKIR) fibers originating from neuronal cell bodies located in the preceding segment. In the adult, the abdominal segmental neurohemal units are more or less fused into a plexus that extends over almost the whole abdominal nerve cord. The adult plexus consists of peripheral nerve branches and superficial nerve fibers beneath the basal lamina of the neural sheath of the nerve cord. During metamorphosis, the LKIR fibers closely follow the restructuration of the perisympathetic organs. In both larvae and adults the LKIR fibers in the neurohemal structures originate from the same cell bodies, which are distributed as ventrolateral bilateral pairs in all abdominal ganglia. The transformation of the series of separated and relatively simple larval neurohemal organs into the larger, continuous and more complex adult neurohemal areas occurs during the first of the two weeks of pupal life. The efferent abdominal LKIR neurons of the moth Agrotis segetum thus belong to the class of larval neurons which persist into adult life with substantial peripheral reorganization occurring during metamorphosis.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0878
    Keywords: Leucokinin I ; Tachykinins ; Nervous system, insect ; Heart innervation ; Phormia terraenovae (Insecta) ; Drosophila melanogaster (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An antiserum against the cockroach neuropeptide leucokinin I (LKI) was used to study peptidergic neurons and their innervation patterns in larvae and adults of three species of higher dipteran insects, the flies Drosophila melanogaster, Calliphora vomitoria, and Phormia terraenovae, as well as larvae of a primitive dipteran insect, the crane fly Phalacrocera replicata. In the larvae of the higher dipteran flies, the antiserum revealed three pairs of cells in the brain, three pairs of ventro-medial cells in the subesophageal ganglion, and seven pairs of ventro-lateral cells in the abdominal ganglia. Each of these 14 abdominal leucokinin-immunoreactive (LKIR) neurons innervates a single muscle of the abdominal body wall (muscle 8), which is known to degenerate shortly after adult emergence. Conventional electron microscopy demonstrates that this muscle is innervated by at least one axon containing clear vesicles and two axons containing dense-cored vesicles. Electronmicroscopical immunocytochemistry shows that the LKIR axon is one of these two axons with dense-cored vesicles and that it forms terminals on the sarcolemma of its target muscle. The abdominal LKIR neurons appear to survive metamorphosis. In the adult fly, the efferent abdominal LKIR neurons innervate the spiracles, the heart, and neurohemal regions of the abdominal wall. In the crane fly larva, dorso-medial and ventrolateral LKIR cell bodies are located in both thoracic and abdominal ganglia of the ventral nerve cord. As in the larvae of the other flies, the abdominal ventrolateral LKIR neurons form efferent axons. However, in the crane fly larva there are two pairs of efferent LKIR neurons in each of the abdominal ganglia and their peripheral targets include neurohemal regions of the dorsal transverse nerves. An additional difference is that in the crane fly, a caudal pair of LKIR axons originating from the penultimate pair of dorso-median LKIR cells in the terminal ganglion innervate the hindgut.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0878
    Keywords: Neurohemal areas ; Neuropeptides ; Monoamines ; Immunocytochemistry ; Nervous system, insect ; Gryllus bimaculatus (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The morphology and position of putative neurohemal areas in the peripheral nervous system (ventral nerve cord and retrocerebral complex) of the cricket Gryllus bimaculatus are described. By using antisera to the amines dopamine, histamine, octopamine, and serotonin, and the neuropeptides crustacean cardioactive peptide, FMRFamide, leucokinin 1, and proctolin, an extensive system of varicose fibers has been detected throughout the nerves of all neuromeres, except for nerve 2 of the prothoracic ganglion. Immunoreactive varicose fibers occur mainly in a superficial position at the neurilemma, indicating neurosecretory storage and release of neuroactive compounds. The varicose fibers are projections from central or peripheral neurons that may extend over more than one segment. The peripheral fiber varicosities show segment-specific arrangements for each of the substances investigated. Immunoreactivity to histamine and octopamine is mainly found in the nerves of abdominal segments, whereas serotonin immunoreactivity is concentrated in subesophageal and terminal ganglion nerves. Immunoreactivity to FMRFamide and crustacean cardioactive peptide is widespread throughout all segments. Structures immunoreactive to leucokinin 1 are present in abdominal nerves, and proctolin immunostaining is found in the terminal ganglion and thoracic nerves. Codistribution of peripheral varicose fiber plexuses is regularly seen for amines and peptides, whereas the colocalization of substances in neurons has not been detected for any of the neuroactive compounds investigated. The varicose fiber system is regarded as complementary to the classical neurohemal organs.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0878
    Keywords: Key words Pigment-dispersing hormone ; Immunocytochemistry ; Central nervous system ; Gastropoda ; Helix pomatia ; Lymnaea stagnalis (Mollusca)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract By using an antiserum raised against a crustacean β-pigment-dispersing hormone (PDH), the distribution and chemical neuroanatomy of PDH-like immunoreactive neurons was investigated in the central nervous system of the gastropod snails, Helix pomatia and Lymnaea stagnalis. The number of immunoreactive cells in the Helix central nervous system was found to be large (700–900), whereas in Lymnaea, only a limited number (50–60) of neurons showed immunoreactivity. The immunostained neurons in Helix were characterized by rich arborizations in all central ganglia and revealed massive innervation of all peripheral nerves and the neural (connective tissue) sheath around the ganglia and peripheral nerve trunks. A small number of Helix nerve cell bodies in the viscero-parietal ganglion complex were also found to be innervated by PDH-like immunoreactive processes. Hence, a complex central and peripheral regulatory role, including neurohormonal actions, is suggested for a PDH-like substance in Helix, whereas the sites of action may be more limited in Lymnaea.
    Type of Medium: Electronic Resource
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