A model for the comparison of pharmacologic agents influencing gallbladder contraction

Investigations on pharmacologic effects on gallbladder contraction must take into consideration the spontaneous motility of the gallbladder. In 20 healthy subjects, we measured the area of the gallbladder sonographically over 10 h at hourly intervals. The spontaneous motility expressed as a coefficient of variation varied between 1.6 and 13% (mean value, 6.3%). Afterwards, we checked the cholecystokinetic action of ceruletide and fatty meal in eight subjects. Here, an alteration of the area by four times the previously found coefficient of variation was defined as significant. A significant contraction occurred earlier after ceruletide administration than after a fatty meal (10 min as compared to 20 min). This lasted longer (40 min. vs. 25 min) and led to a very much more marked reduction in area (69% as compared to 53%). These differences were significant on a 5% level. The end of the contraction did not differ (50 min as compared to 45 min). We conclude that drugs which affect gallbladder contraction can be compared with consideration of spontaneous motility.