Summary
The paired, electrotonically coupled neurosecretory Canopy Cells (CC) of the pond snail Lymnaea stagnalis were microiontophoretically injected with horseradish peroxidase (HRP). Whole mount preparations and ultrathin sections of injected CC were studied to describe in detail the morphology of the CC, their axon tracts and neurohaemal areas. The CC release their secretory product at three different sites, viz. from the soma and from axon terminals in the intercerebral commissure and in the median lip nerve. Neural control over the CC occurs by few synapses found exclusively on the CC axon, not on the cell body. One type of “en passant” synapse was identified. Two morphologically distinct types of synapselike structures (SLS) are numerous. The site of electrotonic coupling between the two CC is most probably located in the cerebral commissure. Serial sectioning showed that the axons contact each other over more than 130 μm. The contact is very intimate and the axon membranes interdigitate in a complex manner. Gap junctions, which are often described as the sites of electrotonic coupling, were not found.
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Ábrahám, A.: Studies on the medial neurosecretory cells in the protocerebrum of the water beetle, Dytiscus marginalis. In: Neurosecretion. The final neuroendocrine pathway, (F. Knowles and L. Vollrath, eds.), p. 203. Berlin-Heidelberg-New York: Springer Verlag 1974
Benjamin, P.R., Swindale, N.V., Slade, C.T.: Electrophysiology of identified neurosecretory neurones in the pond snail Lymnaea stagnalis (L.). In: Neurobiology of invertebrates —Gastropoda Brain. (J. Salánki, ed.), pp. 85–100. Budapest: Adkadémiai Kiadó 1976
Brink, M., Boer, H.H.: An electron microscopical investigation of the follicle gland (cerebral gland) and of some neurosecretory cells in the lateral lobe of the cerebral ganglion of the pulmonate gastropod Lymnaea stagnalis L. Z. Zellforsch. 79, 230–243 (1967)
Burnstock, G., Iwayama, T.: Fine-structural identification of autonomic nerves and their relation to smooth muscle. Progr. Brain Res. 34, 389–404 (1971)
Heuser, J.E., Reese, T.S.: Evidence for recycling of synaptic vesicle membrane during transmitter release at the frog neuromuscular junction. J. Cell Biol. 57, 315–344 (1973)
Korn, H., Faber, D.S.: An electrically mediated inhibition in goldfish medulla. J. Neurophysiol. 38, 452–471 (1975)
Lever, J., Boer, H.H., Duiven, R.J.Th., Lammens, J.J., Wattel, J.: Some observations on follicle glands in Pulmonates. Proc. Kon. Ned. Akad. Wet. C 62, 139–144 (1959)
Normann, T.C.: Neurosecretion by exocytosis. Int. Rev. Cytol. 46, 1–77 (1976)
Redman, S.: Junctional mechanisms at group Ia synapses. Progr. Neurobiol. 12, 33–83 (1979)
Roubos, E.W.: Regulation of neurosecretory activity in the freshwater pulmonate Lymnaea stagnalis (L.) with particular reference to the role of the eyes. Cell Tissue Res. 160, 291–314 (1975)
Roubos, E.W., Moorer-van Delft, C.M.: Synaptology of the central nervous system of the freshwater snail Lymnaea stagnalis (L.), with particular reference to neurosecretion. Cell Tissue Res. 198, 217–235 (1979)
Sotelo, C., Korn, H.: Morphological correlates of electrical and other interactions through low-resistance pathways between neurons of the vertebrate central nervous system. Int. Rev. Cytol. 55, 67–107 (1978)
Swindale, N.V., Benjamin, P.R.: The anatomy of neurosecretory neurones in the pond snail Lymnaea stagnalis (L.). Phil. Trans. R. Soc. B 274, 169–202 (1976)
Vlieger, T.A. de, Roubos, E.W.: Morphological and electrophysiological aspects of the regulation of neurosecretory cell activity in the pond snail Lymnaea stagnalis. In: Comparative endocrinology (P.J. Gaillard and H.H. Boer, eds.), pp. 317–322. Amsterdam-New York-Oxford: Elsevier/North Holland Biomedical Press 1978
Wendelaar Bonga, S.E.: Ultrastructure and histochemistry of the neurosecretory cells and neurohaemal areas in the pond snail Lymnaea stagnalis (L.). Z. Zellforsch. 108, 190–224 (1970)
Wendelaar Bonga, S.E.: Neuroendocrine involvement in osmoregulation in a freshwater mollusc, Lymnaea stagnalis. Gen. Comp. Endocrinol. (suppl.) 3, 308–316 (1972)
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The authors wish to thank Dr. H.H. Boer and Dr. E.W. Roubos for their stimulating criticism during the experiments and the preparation of the manuscript, Prof. Dr. J. Lever for reading the manuscript, and Mr. J. Wijdenes for designing Fig. 12. This investigation was supported by the Foundation for Fundamental Biological Research (BION), which is subsidized by the Netherlands Organization for the Advancement of Pure Research (ZWO)
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van Minnen, J., Reichelt, D. & Lodder, J.C. An ultrastructural study of the neurosecretory canopy cell of the pond snail Lymnaea stagnalis (L.), with the use of the horseradish peroxidase tracer technique. Cell Tissue Res. 204, 453–462 (1979). https://doi.org/10.1007/BF00233656
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DOI: https://doi.org/10.1007/BF00233656