Gallbladder expansion induced by feeding.

By using ultrasound we were able to observe any increase in the size of human gallbladders during feeding. In 91 of 123 cases (74%), the gallbladder expanded for a short time prior to contraction during feeding. The examination on eight patients after gastrectomy and seven patients after a medically induced vagotomy revealed contraction only in response to feeding. In seven normal adults, 200 ml of air injected rapidly into stomach through a gastric tube was seen to induce gallbladder expansion. These results suggest that the gallbladder expands in response to feeding via a cholinergic vago-vagal reflex.