On Adrenergic Influence on Gastric Motility in Chronically Vagotomized Gats

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Abstract

Experiments were performed on chloralosed cats, which had been vagotomized 9–102 days previously. In contrast to the situation in acutely vagotomized cats, recordings of gastric motility revealed pronounced and regular contractions, which persisted after exclusion of spinal pathways but could be completely blocked by small doses of atropine. These contractions therefore appeared to be the result of enhanced activity of the intramural cholinergic ganglionic cells, presumably due to sensitization to local excitatory influences after decentralization.–This type of motility could be markedly inhibited by even weak activation of the gastric adrenergic supply. Intestinal distension, or afferent stimulation of me:enteric nerve fibres as well as efferent low frequency stimulation of the splanchnic supply to the stomach, promptly inhibited the stomach contractions. After administration of atropine the above types of adrenergic activation elicited at most only very weak inhibitory response of the stomach, and then only after a long latency.–The data presented are compatible with the view that the adrenergic fibres to the stomach exert their primary action on stomach motility by inhibiting the intramural cholinergic ganglion cells rather than the smooth muscle cells, responsible for gastric myogenic tone, or by any “presynaptic inhibitory action” on the preganglionic vagal nerve endings.

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