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  • 1
    Electronic Resource
    Electronic Resource
    An ultrastructural in vitro study on the regulation of neurosecretory activity in the freshwater snail Lymnaea stagnalis (L.) with particular reference to Caudo-dorsal cells (1976)
    Springer
    Cell & tissue research 174 (1976), S. 201-219 
    Details
    ISSN: 1432-0878
    Keywords: Neurosecretion ; Lymnaea stagnalis ; Neuron isolation ; Culture ; Quantitative electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neurosecretory Caudo-Dorsal Cells (CDC) in the cerebral ganglia of the freshwater pulmonate snail Lymnaea stagnalis produce an ovulation stimulating hormone. Previously it has been shown that neuronal and non-neuronal inputs are involved in the regulation of their activity. The degree of autonomy of these cells has been investigated by studying with morphometric methods the ultrastructure of CDC maintained in vitro. CDC of isolated cerebral ganglia which were cultured for 7 days show a considerable rate of synthesis, transport and release of neurohormone. Apparently these processes can proceed in the absence of neuronal and hormonal inputs from outside the cerebral ganglia. Completely isolated CDC, however, do not show neurosecretory activity in vitro; active Golgi zones, indicating the formation of neurosecretory elementary granules, are absent from such cells. Isolation does not seem to affect general cell functions such as protein synthesis and respiration. It is suggested that a neuronal input, originating within the cerebral ganglia, is necessary for the stimulation of CDC neurosecretory activity. Techniques are described for the isolation and culture of neurosecretory cells of L. stagnalis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222159
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Morphometric in vitro analysis of the control of the activity of the neurosecretory dark green cells in the freshwater snail Lymnaea stagnalis (L.) (1976)
    Springer
    Cell & tissue research 174 (1976), S. 221-231 
    Details
    ISSN: 1432-0878
    Keywords: Neurosecretion ; Lymnaea stagnalis ; Osmoregulation ; In vitro ; Quantitative electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neurosecretory Dark Green Cells (DGC) in the pleural and parietal ganglia of the freshwater snail Lymnaea stagnalis seem to be involved in osmoregulation. Previous experiments have indicated that changes of the osmolality of the environment induce activity changes of the DGC. Furthermore, it was shown that information on environmental osmolality reaches the DGC via the blood. In the present study right pleural and parietal ganglion complexes were cultured for 3 days in vitro under different osmotic conditions. Quantitative electron microscopy revealed that, compared with the control osmolality (130 mOsm/kg H2O), osmolalities of 160 and 190 mOsm/kg H2O caused a reduced synthesis and an increased storage of neurohormone in the DGC. Apparently, the activity of the DGC depended on the osmotic pressure of the medium. It is proposed that in vivo the osmotic pressure of the blood (which is related to the osmolality of the environment) regulates DGC activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222160
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    In vivo modulation of vincristine-induced neurotoxicity in Lymnaea stagnalis, by the ACTH(4–9)analogue Org 2766 (1996)
    Springer
    Journal of neuro-oncology 30 (1996), S. 173-180 
    Details
    ISSN: 1573-7373
    Keywords: Lymnaea stagnalis ; microtubules ; neurotoxicity ; Org 2766 ; vincristine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The use of the cytostatic agent vincristine (VCR) is limited by the occurrence of peripheral neuropathy. This side-effect is probably caused by interference with axonal microtubules. VCR depolymerizes microtubules and reacts with tubulin to form paracrystals. The potential of a neurotrophic ACTH(4–9) analogue, Org 2766, to counteract peripheral neuropathy caused by cytostatic agents is being investigated. In the present ultrastructural study, modulatory effects of Org 2766 on VCR-induced neurotoxicity were studied in vivo in neurons of the pond snail Lymnaea stagnalis, which has been shown previously to be a suitable test system to investigate neurotoxic side-effects of cytostatic agents. 24 h after treatment with VCR (25 μM), 68.4 ± 34.7 paracrystals were counted per cross-section of the cerebral commissure and the number of microtubules in the axons had been lowered to 46% of the control level. After a survival period of two weeks all paracrystals had disappeared. By that time, no recovery of the axonal microtubular system could be observed. However, post-treatment with Org 2766 (10−6 M) on day 6 after VCR treatment had induced a significant increase in the number of microtubules (+ 55%) on day 7. This beneficial effect lasted for the rest of the experimental period (14 days). These results suggest that post-treatment with Org 2766, i.e. after VCR clearance, can induce long-lasting beneficial effects on VCR-induced neurotoxicity in vivo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00177268
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  • 4
    Electronic Resource
    Electronic Resource
    Ultrastructural neuropathologic effects of Taxol on neurons of the freshwater snailLymnaea stagnalis (1995)
    Springer
    Journal of neuro-oncology 25 (1995), S. 49-57 
    Details
    ISSN: 1573-7373
    Keywords: Taxol ; Cremophor EL ; Org 2766 ; neuropeptidergic cells ; microtubules ; peptide secretion ; Lymnaea stagnalis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cerebral ganglia of the freshwater snailLymnaea stagnalis were incubatedin vitro in 10 μM Taxol for 8 and 24 h. Cremophor EL (0.1%) was used as a diluant. The tissue was processed for electron microscopy. Various ultrastructural parameters were assessed quantitatively. Cremophor EL appeared to seriously affect the cell somata of the multipeptidergic caudodorsal cells. In the Cremophor-controls the mean area of Golgi zones, the percentage dense material (neuropeptides) in these zones, the number of large electron dense granules (these are involved in neuropeptide processing) and the mean nuclear heterochromatin clump size, were significantly smaller than in the Ringer-controls, whereas the number of lipid droplets was higher. All these parameters, except for the lipid droplets, were not different in the Cremophor-controls and the Taxol-treated specimens. After 24 h treatment, but not after 8 h, Cremophor EL furthermore induced an increase in the number of axonal microtubules. It is argued that the results might signify activation of the neurons by Cremophor EL. Taxol induced a significant increase in the number of microtubules in axons and cell somata. Furthermore an increase in the number of Golgi zones was observed, suggesting activated neuropeptide synthesis. In all groups immunostaining with antibodies to neuropeptides produced by the caudodorsal cells was normal. Release of neuropeptide (exocytosis) from axon endings was elevated after Taxol treatment, and exceptionally high in specimens cotreated with Taxol and Org 2766 (incubation time 22 h). The effect of Org 2766 and Taxol on the number of microtubules was cumulative. It is argued that transport of neuropeptide granules from the cell somata to the axon terminals was not affected by Taxol. It is concluded that Taxol neurotoxicity is probably not due to impeded microtubular axonal transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01054722
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    Paper (German National Licenses)
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