Gallbladder contraction as a test for vagal innervation.

A subthreshold dose of carbachol was used to test gallbladder reaction in a series of patients before operation, after truncal vagotomy with antrectomy (TA) and after parietal cell vagotomy (PCV) because of duodenal ulcer. A small but statistically significant size reduction was seen before operation, a much higher reduction after TA and after PCV, that after TA being significantly higher than after PCV. It must be assumed that after PCV a number of gallbladders is in a state of denervation.