Effects of intravenous vasoactive intestinal peptide (VIP) on gallbladder function in the cat.

The influence of vasoactive intestinal peptide (VIP) on the concentrating mechanism and the motility in the feline gallbladder has been studied in vivo. A perfusion technique made possible a simultaneous study of the motility and of the net transport of water and electrolytes across the gallbladder wall. It was found that an intravenous infusion of VIP relaxes the gallbladder and induces a net fluid secretion into its lumen. The net absorption of chloride ions was markedly reduced, whereas the net transport of sodium, potassium, and bicarbonate was reversed from an absorption into a secretion. Owing to the presence of VIP-containing nerve fibers in the gallbladder wall, a physiological significance for the secretory gallbladder response to VIP is suggested.