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THE EFFECT OF OPTIC TENTACLE REMOVAL ON THE TRANSMITTER CONTENT OF THE GIANT SEROTONIN CELL OF HELIX ASPERSA
Author(s) -
Osborne N. N.,
Cottrell G. A.
Publication year - 1972
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1972.tb01290.x
Subject(s) - tentacle (botany) , neuron , axon , serotonin , biology , helix pomatia , anatomy , biophysics , neuroscience , depolarization , ganglion , helix (gastropod) , chemistry , snail , gastropoda , biochemistry , zoology , ecology , receptor
— There is a giant serotonin‐containing neuron in each metacerebral ganglion of the snail Helix pumntia. Much of the amine is localized in small granular vesicles (COTTRELL and OBSORNE, 1970) and evidence for serotonin having a transmitter role in each giant neuron is very strong (COTTRBLL, 1970a, b). It is shown that the content of serotonin in each giant neuron is reduced by ablation of the optic tentacle. Maximum depletion of amine (about 70 per cent) was observed at 6–8 days after the operation. Unilateral depletion followed removal of only one tentacle. To examine the observations more closely, electrophysiological experiments were also made to determine any neuronal connection between the tentacles and the serotonin‐containing neurons. No evidence was found for the presence of an axon from either giant neuron in the nerves leading to the tentacles. Stimulation of the nerves supplying the tentacles caused both depolarization and spike firing, and hyperpolarization and inhibition of the giant neurons. It is possible that the depletion of serotonin following ablation of the optic tentacles results from an interruption of the nerve fibres mediating in one or both of the observed types of input.