Prostaglandin E2 stimulates ion transport in prairie dog gallbladder

The effects of prostaglandins, and specifically prostaglandin E2, on gallbladder ion transport were examined in the prairie dog. Gallbladders were mounted in an Ussing chamber and baseline short-circuit current, potential difference, and tissue resistance were measured. Addition of arachidonic acid (10(-4) M, mucosal surface) produced sustained elevations in short-circuit current and potential difference (P < 0.05), with mild reductions in resistance. In a second set of tissues, indomethacin exposure (10(-6) M) resulted in a significant (P < 0.02) decrease in short-circuit current and potential difference, with an increase in resistance. Subsequent addition of prostaglandin E2 (10(-7) M, serosal surface) fully reversed these changes and led to a significant increase in short-circuit current and potential difference (P < 0.001) with a return of resistance to baseline values. These findings suggest that endogenous prostaglandins mediate gallbladder ion transport.