title: Some effects of proctolin on the cardiac ganglion of the Maine Lobster, Homarus americanus (Milne Edwards).
abstract: The neuropeptide proctolin has excitatory effects on the isolated lobster cardiac ganglion. Selective application to the anterior cell body region produces a dose-dependent (10(-8)--10(-5) M) prolonged depolarization of large anterior cells as well as marked increases in burst frequency and/or duration. In ganglia which have been silenced with tetrodotoxin, proctolin application to anterior cells elicits long-lasting depolarizing responses which are accompanied by a 10-30% increase of the apparent membrane input resistance. Higher proctolin concentrations produce high-frequency trains of driver potentials. It is proposed that a proctolin like peptide may serve a neurohumoral role in the lobster cardiac ganglion and that the anterior motor neurons exhibit endogenous rhythmicity in its presence.
mesh_terms: D000818:Animals; D004553:Electric Conductivity; D005724:Ganglia / Q000187:drug effects / Q000502:physiology*; D006321:Heart / Q000294:innervation*; D008121:Nephropidae; D009479:Neuropeptides; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D009842:Oligopeptides / Q000494:pharmacology*; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D009479:Neuropeptides; D018377:Neurotransmitter Agents; D009842:Oligopeptides; D013779:Tetrodotoxin; C011536:proctolin