ELICITATION OF REFLEX VAGAL RELAXATION OF STOMACH FROM PHARYNX AND ESOPHAGUS IN CAT

Distension of different parts of the esophagus in chloralosed cats caused prompt and pronounced relaxation of the stomach. Even slight distension was sufficient to elicit gastric relaxation, and the degree of relaxation vaned with that of the esophageal distension. The gastric relaxatory response was shown to be due to elicitation of a vago‐vagal reflex to the stomach. The response could be elicited also after exclusion of spinal connections, but disappeared after vagotomy. It could not be blocked by atropine or guanethidine. It thus resembled the gastric relaxation obtained by direct electric stimulation of the vagal “relaxatory” fibres to the stomach. It is concluded that these fibres constitute the efferent pathway of the observed esophageo‐gastric vago‐vagal relaxatory reflex.—Furthermore, a similar gastric relaxation, mediated via the vagal efferent relaxatory fibres, was recorded in connection with pharyngeally elicited swallowing. It is assumed that the gastric relaxation pattern described plays an essential role in “receptive relaxation” of the stomach during deglutition. © 1969 Scandinavian Physiological Society