Bile evacuation induced by hypothalamic stimulation in dogs.

Abstract

To investigate the role of the central nervous system in the cephalic phase of gallbladder emptying, the effects of electrical stimulation of the hypothalamus on the gallbladder and sphincter of Oddi and on bile flow rate were studied in anesthetized dogs. Stimulation of the anterior hypothalamic area induced gallbladder contraction and simultaneous relaxation of the sphincter without a significant increase in plasma cholecystokinin concentration. The bile flow rate was facilitated by stimulation of the same area. These responses were obtained even in dogs with cervical cord transection and were abolished by cervical vagotomy. The contraction response in the gallbladder was prevented by atropine, but a slight relaxation response in the sphincter remained. On the other hand, stimulation of the posterior hypothalamic area induced gallbladder relaxation and contraction or relaxation in the sphincter. The bile flow rate was decreased by stimulation of the same area. These responses were still obtained after vagotomy. These results indicate that the anterior hypothalamic area and the vagus nerves play an important role in gallbladder emptying in the cephalic phase.