Effect of Cholecystokinin, Gastrin, Secretin, and Glucagon on Human Gallbladder Muscle in Vitro

A method was devised to study the action of gastrointestinal hormones on the motility of strips of human gallbladder muscle in vitro. Cholecystokinin-pancreozymin (CCK-PZ) in concentrations of 4 units/100 ml and greater caused progressive shortening. With increased concentrations, the latent period before contraction was briefer. CCK-PZ also caused an increase in the frequency, but not the amplitude, of superimposed contraction waves. The mean duration of action of CCK-PZ was 18 min. Synthetic secretin at 10 units/100 ml had about one sixth of the activity of a similar concentration of CCK-PZ; gastrin and glucagon had no effect.