Canine gallbladder cyclic motor activity.

We investigated whether the gallbladder has cyclic motor activity similar to that of the stomach, lower esophageal sphincter, and sphincter of Oddi in the fasted state. We found that the canine gallbladder infundibulum exhibited a cyclic burst of short duration (69 +/- 3 s) contractions that were closely associated with phase III activity of the antrum. The cyclic motor activity was sometimes less prominent or absent in the body and the fundus of the gallbladder. The mean period of gallbladder cyclic motor activity was not significantly different from the mean period of phase III activity in the stomach and the duodenum. The cyclic bursts of gallbladder contractions lasted for 21 +/- 2 min. The gallbladder cyclic motor activity started at about the same time as the antral phase III activity, and both of these activities started approximately 12 min earlier than the duodenal phase III activity. In addition to the aforementioned cyclic bursts of contractions, the gallbladder sometimes exhibited long duration (6.4 +/- 0.6 min) contractions that occurred irregularly and unpredictably during the duodenal migrating motor complex cycle. We conclude that during fasting the canine gallbladder has a cyclic motor activity that is temporally related to phase III activity of the stomach and the duodenum. The role of short duration phasic contractions during cyclic motor activity may be to periodically stir gallbladder contents, whereas the long duration contractions may partially empty the gallbladder in the fasted state.