Ba++ on the resting frog stomach: effects on electrical and secretory parameters.
Ba++ added to the nutrient solution bathing the resting frog stomach increased resistance, decreased the PD, and stimulated acid secretion. Under short-circuit conditions, the increase in H+-secretory rate was accompanied by a decrease in short-circuit current (I-sc). These changes were reversed by NaSCN (10 mM), suggesting that Ba++ had not impaired the current-generating mechanism per se. Histamine-induced acid secretion was associated with an increase in net Cl- flux, particularly in the N yields S flux (JNS). Ba++ increased acid secretion with no increase in JNS and a decrease in net Cl- flux. The effects of Ba++ were amplified by low-Cl- solutions. Histamine, in the presence of Ba++ and low-Cl- solutions, increased acid secretion and transmucosal resistance, suggesting the operation of a neutral pump in the secretion of HCl. It is concluded that Ba++ limits Cl- entry and also acts as a secretagogue.
D000818:Animals; D001464:Barium / Q000494:pharmacology*; D002712:Chlorides / Q000378:metabolism; D003864:Depression, Chemical; D004594:Electrophysiology / Q000187:drug effects*; D005750:Gastric Juice / Q000378:metabolism*; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D011188:Potassium / Q000378:metabolism; D011892:Rana catesbeiana; D013268:Stimulation, Chemical; D013270:Stomach / Q000187:drug effects*; D013861:Thiocyanates / Q000494:pharmacology
D002712:Chlorides; D013861:Thiocyanates; D001464:Barium; D006632:Histamine; D011188:Potassium