title: Identification of three further giant neurons, r-APN, INN and FAN, in the caudal part on the dorsal surface of the suboesophageal ganglia of Achatina fulica Férussac.
abstract: In addition to the neurons of Achatina fulica Férussac examined previously, three more giant neurons, r-APN (right-anterior pallial neurons), INN (intestinal nerve neuron) and FAN (frequently autoactive neuron), were identified in the suboesophageal ganglia of the same animal. R-APN (200-250 microns in diameter), the somatic membrane of which was usually silent, was found near the exit of the right anterior pallial nerve in the right parietal ganglion. The most important feature in identifying the neuron is the one-by-one correspondence of somatic spikes to impulses in the right anterior pallial and the left anterior pallial nerves. R-APN was excited markedly by dopamine, 5-hydroxytryptamine, L-homocysteic acid, erythro-beta-hydroxy-L-glutamic acid and acetylcholine, and inhibited by GABA. INN (150-200 microns in diameter), which was also silent, was situated near the intestinal nerve in the visceral ganglion. INN somatic spikes corresponded to the impulses in the intestinal nerve. INN was excited by 5-hydroxytryptamine and histamine. Acetylcholine had biphasic effects (inhibitory followed by slight excitatory). FAN (100-150 microns in diameter), showing frequent spike discharges, about 60-120/min, was situated somewhat further from the exit of the left posterior pallial nerve in the visceral ganglion. No clear correspondence was observed between the FAN somatic spikes and impulses of any nerves. FAN was excited by 5-hydroxytryptamine, GABA and acetylcholine, and inhibited by octopamine and erythro-beta-hydroxy-L-glutamic acid.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D002395:Catecholamines / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000494:pharmacology; D005724:Ganglia / Q000166:cytology; D006632:Histamine / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D009474:Neurons / Q000166:cytology / Q000502:physiology; D012908:Snails / Q000033:anatomy & histology* / Q000502:physiology
chemical_list: D000596:Amino Acids; D002395:Catecholamines; D007211:Indoles; D004744:Enkephalin, Methionine; D006632:Histamine