Effects of bile salts on amphibian gastric mucosa

The effect of five different bile salts on the mucosal or serosal surface of isolated bullfrog gastric mucosa was investigated. Serosal exposure (30 min) to 15-40 mM taurocholate (TCA) or taurodeoxycholate (TDCA), 10-40 mM deoxycholate (DCA), or 2.5-7.5 mM cholate (CA) typically produced a marked increase in resistance (R) and a decrease in potential difference (PD), short-circuit current (I-sc), and H+ secretion. Flux of 36Cl from serosal to mucosal solution decreased progressively. The flux of [14C]sucrose across the mucosa was slightly decreased. Microscopy showed condensation of the parietal cells. Mucosal exposure (30 min) at concentrations above 2.5 mM DCA or CA and 15 mM TCA and TDCA caused a marked decrease in R, PD, I-sc, and H+ secretion, and the flux of [14C]sucrose across the mucosa was increased. Extreme destruction of the surface mucous cells was the primary histologic finding. The effect of dehydrocholate was identical to that of TCA. Mucosal bile salts cause an increased permeability primarily by injury of the surface epithelium whereas serosal bile salts affected primarily the oxyntic cells.