[Some properties of the non-adrenergic inhibitory potentials in the duodenal smooth muscle cells of the guinea-pig].
The inhibitory potentials (i.p.s) in the longitudinal and circular smooth muscle cells of the guinea-pig duodenum were recorded intracellularly. The amplitude and the time course of the i.p.s were similar in both muscle cells. The i.p.s were not blocked by atropine and guanethidine. Thus, the i.p. has non-cholinergic and non-adrenergic nature. Paired pulse with various intervals evoked two i.p.s. The amplitude of the second i.p. was smaller than that of the first. This decrease in the amplitude may be due to decrease in an amount of the released inhibitory transmitter. The i.p.s in the longitudinal muscle and the tension in the longitudinal direction were recorded simultaneously. No change in the tension was observed when the i.p.s were evoked. In the active preparations, the spontaneous action potentials were inhibited by the evoked i.p.s and the tension was reduced. The post-stimulus depolarization was intimately associated with the evoked i.p.s. The magnitude and the duration of the post-stimulus depolarization were depended on the preceding i.p.s. The evoked i.p.s in the longitudinal and circular muscle cells of the duodenum and the ileum were not affected by the periarterial nerve stimulation.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004386:Duodenum / Q000294:innervation / Q000502:physiology*; D004558:Electric Stimulation; D006145:Guanethidine / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000294:innervation / Q000502:physiology; D010525:Peripheral Nerves / Q000502:physiology
D001285:Atropine; D006145:Guanethidine