Effects of stimulation of the hypothalamic area on pancreatic exocrine secretion in dogs

The effects of electrical or chemical (0.1 M dl-homocysteic acid) stimulation of the hypothalamus on pancreatic exocrine secretion were studied in chloralose-anesthetized and hemispherectomized dogs whose pyloric sphincter had been ligated. Excitatory pancreatic flow responses with frequently increased antral contractility and small changes in blood pressure were induced by stimulation of the ventral and dorsal portions of the anterior hypothalamic area, the lateral part of the middle hypothalamus, and the mamillary body. The inhibitory pancreatic responses with reduced antral and corpus contractility and elevated blood pressure were elicited by stimulation of the posterior hypothalamic area, the middle portion of the anterior hypothalamus and the most dorsal area of the hypothalamus. Both excitatory and inhibitory responses were obtained even in dogs with cervical cord transection. The excitatory responses and some of the inhibitory ones were abolished by vagotomy or atropine, but some inhibitory responses remained even after vagotomy. These results indicate that hypothalamic stimulation induced both excitatory and inhibitory responses in pancreatic exocrine secretion via the vagus and other routes.