Ba++ on the resting frog stomach: effects on electrical and secretory parameters

Authors:
  • PRPk Rangachari
    Pk Rangachari
  • KMK. G. Mandel
    K. G. Mandel
  • JMJ. A. McRoberts
    J. A. McRoberts
  • GBG. Beuerlein
    G. Beuerlein
  • EFE. S. Foster
    E. S. Foster
  • KDK. Dharmsathaphorn
    K. Dharmsathaphorn
  • SSS S Sanders
    S S Sanders
  • RSR L Shoemaker
    R L Shoemaker
  • WRW S Rehm
    W S Rehm
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Abstract
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.