Effects of hydrostatic pressure on fluid transfer by the isolated gallbladder.

The influence of hydrostatic pressure elevation on fluid absorption by the isolated guinea pig gallbladder was determined following addition of various smooth muscle spasmogens to the serosal bathing medium. Acetylcholine, prostaglandin E1 and ouabain increased intraluminal pressure from about 4 cm H2O to 13 cm H2O. The pressure increase was associated with a marked but transient stimulation in fluid transfer. The same phenomenon was observed following an increase in hydrostatic pressure by addition of Ringer's solution to the gallbladder lumen. Evidence is presented to support the hypothesis that this phenomenon represents the extrusion of an edema from the gallbladder wall. Two observations favour this explanation: 1. The wet weights of gallbladder subjected to high intraluminal hydrostatic pressure were only one third of those at low pressure. 2. Microscopic examination of the wall of gallbladders at low pressure showed a marked submucosal edema.