Effects of E prostaglandins on canine gastric potential difference.

Measurement of the gastric transmucosal potential difference (PD) was used to study the effect of gastric antisecretory prostaglandins on the integrity of the gastric mucosa of the Heidenhain pouch dog. Intragastric administration of SC-29333 [(+/-)-15-deoxy-16-alpha,beta-hydroxy-16-methyl PGE1 methyl ester] slightly but significantly increased the transmucosal PD when compared to vehicle control. In addition, SC-29333 administered either intravenously or intragastrically, significantly inhibited the PD fall induced by aspirin, a well-established barrier breaker. In contrast, the intragastric administration of 16,16-dimethyl PGE2 methyl ester (Me-PGE2) significantly lowered the transmucosal PD and failed to modify the actions of aspirin on the integrity of the gastric mucosa. However, the intravenous administration of either prostaglandin did not affect the basal transmucosal PD values. These studies suggest that SC-29333 may strengthen the integrity of the gastric mucosal barrier against aspirin, and this could have important therapeutic potential.