Central Stimulation of the Vagi and Gastric Secretion

Abstract

That gastric secretion may be centrally stimulated was first shown by Pavlov in 1890 (1). After first conditioning his animals to the environment of the laboratory, he was able to elicit a definite secretory response, high in acid and pepsin concentration, by sham-feeding a mixture of meat and water. He also showed that this response could be abolished by section of the vagi, proving that the efferent fibers conducting the impulses were located in the vagal trunk. | After the discovery, isolation and purefication of insulin by Banting and Best in 1922 (2), its physiological and pharmacological effects were studied by a multitude of workers. The gastric secretory effect of insulin hypoglycemia was shown by La Barre and de Cespedes in 1931 (3) by cross-circulation experiments in which the hypoglycemic blood of one dog was perfused into the carotid arteries of a second intact dog. Shortly afterwards, a definite increase in gastric secretion was observed in the intact animal. The effect could be shown to be by way of the vagi, since, following section of the vagal trunk the effect was abolished. La Barre and de Cespedes concluded that insulin hypoglycemia stimulated the vagal nucleus in the medulla which in turn stimulated the vagal trunk which increases the production of acid and pepsin in the fundus of the stomach. Thus an invaluable aid was discovered which has been of great importance in the field of gastroenterology.