Slow hyperpolarizing action of tryptamine on myenteric neurons of the isolated guinea-pig ileum.
In the present study, tryptamine produced a slow hyperpolarization in a few neurons other than a slow depolarization in myenteric neurons of the isolated guinea-pig ileum. Neither the adrenergic neuron blocker, guanethidine nor the 5-hydroxytryptamine uptake inhibitor, zimelidine, which can inhibit the release of 5-hydroxytryptamine from enteric neurites induced by tryptamine (M. Takaki et al. (1985) Neuroscience 16, 223-240), affected this slow hyperpolarization. Therefore, it was concluded that the slow hyperpolarization induced by tryptamine in myenteric neurons was not mediated via the release of 5-hydroxytryptamine or noradrenaline. It might be possible that the hyperpolarization was induced by a direct action of tryptamine on myenteric neurons per se.
Takaki
M
M
Department of Physiology, Okayama University Medical School, Japan.
Mizutani
M
M
Jin
J G
JG
Nakayama
S
S
D000818:Animals; D004594:Electrophysiology; D006145:Guanethidine / Q000494:pharmacology; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects / Q000294:innervation*; D009197:Myenteric Plexus / Q000187:drug effects / Q000502:physiology*; D014363:Tryptamines / Q000494:pharmacology*; D015031:Zimeldine / Q000494:pharmacology
D014363:Tryptamines; D015031:Zimeldine; D006145:Guanethidine