Oral water causes emptying of the human gallbladder through actions of vagal stimuli rather than motilin.

A drink of water was found to cause partial emptying of the human gallbladder in parallel with the release of motilin. The water-induced effect on the gallbladder was abolished by atropine, whereas the release of motilin remained unchanged. Exogenous infusions of porcine motilin aimed at achieving either a physiological or a pharmacological plasma motilin increment were both without effect on gallbladder dynamics as compared with saline infusions. It is concluded that the water-induced gallbladder emptying is vagally dependent. Furthermore, the results suggest that motilin does not cause gallbladder emptying in man.