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  • 1
    Electronic Resource
    Electronic Resource
    Actions and interactions of proprioceptors of the locust hind leg coxo-trochanteral joint (1985)
    Springer
    Journal of comparative physiology 157 (1985), S. 73-82 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The coxo-trochanteral joint of the locust hindleg is supplied with five mechanoreceptive sense organs: A hairplate (HP) and a row of hairs (RH), two strand receptors (SR1, SR2) and a muscle receptor organ (MRO) (BrÄunig 1982). We report here an investigation of these mechanoreceptors with regard to their afferent responses to static and dynamic mechanical stimulation. 2. The only receptor suited for continuous measurement of joint position is the HP: its units are active over the entire range of possible joint positions and their number increases in proportion to the degree of joint levation (Fig. 3). The RH complements the HP as an additional sensor for extreme levation (Fig. 4). 3. Both SR are sensitive to the dynamic phase of joint depressions. Units of the multicellular SR1 respond over the entire range of joint movements, the single unit of SR2 is tuned to the lower half of that range (Fig. 5). 4. The sensory cell of the MRO is activated when the organ is stretched during depression of the joint (Fig. 6). Increasing slack of the organ during levation is compensated by activation of its receptor muscle. The MRO motor neuron is progressively excited with increasing joint levation, mainly by HP and RH (Figs. 6, 7, 8). 5. During stimulation of internal mechanoreceptors (SR1, SR2, and the sensory cell of the MRO) and during spontaneous motor activity the MRO motor neuron is co-activated with levator motor neurons (Figs. 9, 10). This mechanism may help to compensate for slack before the reflexes from HP and RH set in (see 4.). 6. The motor neuron of the MRO receptor muscle is not only activated by sense organs of the coxo-trochanteral joint, but also by proprioceptors of neighboring joints (Fig. 11). 7. Since all coxo-trochanteral joint receptors exert reflexes on motor neurons of power muscles and the efferent unit of the MRO, manipulation and extirpation of any one receptor must result in direct effects on the motor output of the metathoracic ganglion, but also additional indirect effects due to altered operation of the MRO.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00611097
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  • 2
    Electronic Resource
    Electronic Resource
    Actions and interactions of proprioceptors of the locust hind leg coxo-trochanteral joint (1985)
    Springer
    Journal of comparative physiology 157 (1985), S. 83-89 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Reflexes involving hind leg muscles during movement of the coxo-trochanteral joint were recorded after total ipsilateral deafferentation except for one of two groups of mechanoreceptors. These were (i) HP and RH, and (ii) SR1, SR2 and MRO. 2. Both groups of receptors influence coxotrochanteral and subcoxal, but not femoro-tibial muscles (Figs. 2, 3; Table 1). 3. Many subcoxal muscles are activated by both antagonistic groups of receptors. Their co-contraction may lock the subcoxal joint in a rigid position, thereby making it a firm support for resistance reflexes in more distal joints. 4. Reflexes onto coxo-trochanteral muscles were studied in more detail by direct selective mechanical stimulation of single receptors. All receptors elicit typical resistance reflexes: Sense organs sensitive to joint depression (SR1, SR2, MRO) activate levator motor units and inhibit depressor activity (Fig. 4). Sense organs sensitive to levation (HP, RH) cause analogous reactions of opposite sign (Fig. 5). 5. Tonic excitation by proprioceptors is necessary to maintain a certain level of spontaneous activity in certain motor neurons. For example after HP and RH extirpation, spontaneous activity of depressor motor units ceases, MRO ablation has comparable effects on levator units (Table 1).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00611098
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  • 3
    Electronic Resource
    Electronic Resource
    Serotonin-immunoreactive and dopamine-immunoreactive neurones in the terminal ganglion of the cricket, Acheta domestica: Light- and electron-microscopic immunocytochemistry (1987)
    Springer
    Cell & tissue research 250 (1987), S. 167-180 
    Details
    ISSN: 1432-0878
    Keywords: Serotonin ; Dopamin ; Immunocytochemistry ; Terminal ganglion ; Acheta domestica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution and ultrastructure of serotonin- and dopamine-immunoreactive (5-HTi and DAi) neurones have been investigated in the terminal ganglion of the cricket, Acheta domestica, using a pre-embedding chopper technique. Special attention has been paid to the immunoreactive structures in the neuropil. 5-HTi structures are extensively distributed and densely packed throughout the 5 neuromeres of the terminal ganglion and originate from several interneurones and efferent neurones. In contrast, DAi fibres are distributed sparsely although they extend to all neuromeres of the ganglion and originate from 6 interneurons only. For both 5-HTi and DAi neurones characteristic axonal projections and branching patterns can be distinguished. The 5-HTi axons exhibit rich varicose arborizations, whereas DAi neurones possess fewer varicosities in the neuropil. Electron microscopy shows that 5-HTi varicosities contain small (∼ 60 nm) and large (∼ 100 nm) agranular vesicles, and large (∼ 100 nm) granular vesicles, whereas in DAi varicosities small (∼ 60 nm) agranular and large (∼ 100 nm) granular vesicles are seen. Both 5-HTi and DAi varicosities form synaptic contacts. We conclude that both serotonin and dopamine may be used as neurotransmitters in the terminal ganglion of the cricket.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214668
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  • 4
    Electronic Resource
    Electronic Resource
    The efferent innervation of the genital chamber by an identified serotonergic neuron in the female cricket Acheta domestica (1988)
    Springer
    Cell & tissue research 252 (1988), S. 449-457 
    Details
    ISSN: 1432-0878
    Keywords: Serotonin (5-HT) ; Genital chamber ; Immuno-cytochemistry ; Electron microscopy ; Cricket, Acheta domestica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The serotonergic innervation of the genital chamber of the female cricket, Acheta domestica, has been investigated applying anti-serotonin (5-HT) immunocyto-chemistry at both light- and electron-microscopic levels as well as using conventional electron microscopy. Whole mount and pre-embedding chopper techniques of immuno-cytochemistry reveal a dense 5-HT-immunoreactive network of varicose fibers in the musculature of the genital chamber. All of these immunoreactive fibers originate from the efferent serotonergic neuron projecting through the nerve 8v to the genital chamber (Hustert and Topel 1986; Elekes et al. 1987). At the electron-microscopic level, 5-HT-immunoreactive nerve terminals, which contain small (50–60 nm) and large (∼ 100 nm) agranular vesicles as well as granular vesicles (∼100nm), contact the muscle fibers or the sarcoplasmic processes without establishing specialized neuromuscular connections. In addition to the 5-HT-immunoreactive axons, two types of immunonegative axons can also be found in the musculature. By use of conventional electron microscopy, three ultrastructurally distinct types of axon processes can be observed, one of which resembles 5-HT-immunoreactive axons. While the majority of the varicosities do not synapse on the muscle fibers, terminals containing small (50–60 nm) agranular vesicles occasionally form specialized neuromuscular contacts. It is suggested that the 5-HTergic innervation plays a non-synaptic modulatory role in the regulation circular musculature in the genital chamber of the cricket, while the musculature as a whole may be influenced by both synaptic and modulatory mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214388
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  • 5
    Electronic Resource
    Electronic Resource
    The coxo-trochanteral muscle receptor organ of locusts (1986)
    Springer
    Cell & tissue research 243 (1986), S. 517-524 
    Details
    ISSN: 1432-0878
    Keywords: Muscle receptor organ ; Electron microscopy ; Tubular body ; Mechanosensory transduction ; Locust, Locusta migratoria migratorioides (R.&F.)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The coxo-trochanteral muscle receptor organ of the hind leg of the locust Locusta migratoria migratorioides (R.&F.) has been investigated by use of scanning and transmission electron microscopy with special emphasis on its distal attachment site. The overall morphology of the receptor muscle, the sensory neuron and its dendrites was found to share many common features with other arthropod sense organs of that type with two important differences: (1) the connective tissue segment (= intercalated tendon) is extremely short compared to that of other muscle receptor organs; (2) the naked dendritic terminals of the non-ciliated, multipolar sensory neuron of the organ contain clusters of microtubules, interconnected by an amorphous matrix, that resemble the tubular bodies of ciliated, epithelial receptor cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218058
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  • 6
    Electronic Resource
    Electronic Resource
    Location and major postembryonic changes of identified 5-HT-immunoreactive neurones in the terminal ganglion of a cricket (Acheta domesticus) (1986)
    Springer
    Cell & tissue research 245 (1986), S. 615-621 
    Details
    ISSN: 1432-0878
    Keywords: 5-HT ; Insect neurones ; Terminal ganglion ; Sexual dimorphism ; Developmental changes ; Cricket, Acheta domesticus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the terminal ganglion of the cricket, Acheta domesticus, the somata of certain interneurones and efferent neurones consistently react to 5-HT immunohistochemistry. There are serially homologous pairs of bilateral interneurones seen in the neuromeres of the 7th to the 10th segment and hindgut neurones with their somata located at the posterior median end of the ganglion. In adult crickets, pairs of large efferent neurones with lateral somata supply specific genital muscles in the 8th and the 9th segment of females. In males, only one pair of these efferent neurones supplies genital muscles of the 9th segment only. These identified 5-HT-immunoreactive neurones are not detected in larval crickets before development of the genital apparatus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218563
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