Summary
The morphology, axonal arborization and ultrastructure of synaptic connections of the V21 giant neuron in the visceral ganglion of the snail Helix pomatia has been investigated following intracellular labelling with horseradish peroxidase. The V21 neuron establishes several afferent and efferent axo-axonic connections, mainly along the first half of the primary axon. Collaterals of 200–300 μm length originate from the primary axon, which shows further arborization, and both afferent and efferent synaptic contacts are formed on these fine axon profiles. Afferent and efferent contacts of the cell occur within very short distances of a few micrometers. On the basis of ultrastructure and vesicle and granule content, several afferent terminals can be distinguished on V21 labelled axon profiles. The majority of these afferent terminals resembles peptidergic-(neurosecretory)-like terminals. This finding supports the possible transmitter role of neuropeptides in the central nervous system of gastropods. Our results are consistent with and provide morphological evidence for recent electrophysiological observations suggesting that, in addition to integrating input, the V21 neuron functions as an interneuron in Helix central nervous system.
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Bailey CH, Thompson EB, Castellucci VF, Kandel ER (1979a) Ultrastructure of the synapses of sensory neurons that mediate the gill-withdrawal reflex in Aplysia. J Neurocytol 8:415–444
Bailey CH, Castellucci VF, Koester J, Kandel ER (1979b) Cellular studies of peripheral neurons in siphon skin of Aplysia californica. J Neurophysiol 42:530–557
Elekes K (1979) Light and electron microscopic autoradiography of 3H-dopamine uptake in the ganglia of the freshwater mussel, Anodonta cygnea L. Acta Biol Acad Sci Hung 30:223–234
Elekes K (1980) Fine structural aspects of monoamine storage and identification of aminergic elements in the central nervous system of molluscs. In: Salánki J, Turpaev T (eds) Neurotransmitters. Comparative aspects. Akadémiai Kiadó Budapest, pp 79–100
Elekes K, Vehovszky Á, Salánki J (1983) Ultrastructure of synaptic connections of a bimodal pacemaker giant neuron in the central nervous system of Helix pomatia L. Neuroscience 8:617–629
Muller KJ, McMahan UJ (1976) The shapes of sensory and motor neurones and the distribution of their synapses in ganglia of the leech: a study using intracellular injection of horseradish peroxidase. Proc R Soc Lond B 194:481–499
Pentreath VW (1976) Ultrastructure of the terminals of an identified 5-hydroxytryptamine-containing neurone marked by intracellular injection of radioactive 5-hydroxytryptamine. J Neurocytol 5:43–61
Pentreath VW, Berry MS (1976) Ultrastructure of the terminals of an identified dopamine-containing neurone marked by intracellular injections of radioactive dopamine. J Neurocytol 4:249–260
Pentreath VW, Berry MS (1978) Radioautographic study of 5-hydroxytryptamine-containing nerve terminals in central ganglia of Planorbis corneus: comparison with other species and characteristics of the serotonergic nerve terminal. J Neurocytol 7:443–459
Reynolds ES (1963) The use of lead citrate in electron microscopy. J Cell Biol 17:208–212
Sakharov DA, Salánki J (1969) Physiological and pharmacological identification of neurons in the central nervous system of Helix pomatia L. Acta Physiol Hung 35:19–30
Spurr AR (1969) A low viscosity epoxy resin embedding medium for electron microscopy. J Ultrastruct Res 26:31–41
S.-Rózsa K (1976) Neuronal network underlying the regulation of heart beat in Helix pomatia L. In: Salánki J (ed) Neurobiology of invertebrates. Gastropoda brain. Akadémiai Kiadó Budapest, pp 597–613
S.-Rózsa K (1979) Analysis of the neural network regulating the cardiorenal system in the central nervous system of Helix pomatia L. Am Zool 19:117–128
S.-Rózsa K (1982) Various transmitters as filters in transferring information in an identified neural network of gastropods. Comp Biochem Physiol 72C:375–386
S.-Rózsa K, Zhuravlev V (1981) Central regulation and coordination of the activity of cardiorenal system and pneumostoma at suboesophageal ganglia of Helix pomatia L. Comp Biochem Physiol 69A: 85–98
Stefano GB, Vadász I, Hiripi L (1980a) Methionine-enkephalin inhibits the bursting activity of the Br-type neuron in Helix pomatia L. Experientia 36:666–667
Stefano GB, S.-Rózsa K, Hiripi L (1980b) Actions of methionine enkephalin and morphine on single neuronal activity in Helix pomatia L. Comp Biochem Physiol 66C:193–198
Thompson EB, Schwartz JH, Kandel ER (1976) A radioautographic analysis in the light and electron microscope of identified Aplysia neurons and their processes after intrasomatic injection of 3H-L-fucose. Brain Res 112:251–281
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Elekes, K., -Rózsa, K.S. Synaptic organization of a multifunctional interneuron in the central nervous system of Helix pomatia L.. Cell Tissue Res. 236, 677–683 (1984). https://doi.org/10.1007/BF00217238
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DOI: https://doi.org/10.1007/BF00217238