Inhibition of H+ secretion in the frog gastric mucosa by ATP and related compounds.

Addition of adenosine triphosphate (ATP) to the nutrient (submucosal-facing) solution of the histamine-stimulated in vitro frog (Rana pipiens) gastric mucosa produces a marked reduction in the H+ secretory rate and an increase in transmucosal potential difference (PD) and resistance in both Cl- and Cl-free media. The effects are reversible upon removal of ATP. The threshold concentration is between 1 and 2 mM, and 5 mM produce maximal inhibition. It is shown that the effects of ATP are not due to a change in pH or osmolarity of the nutrient fluid, or to a decrease in the Ca2+ and/or Mg2+ activities of the nutrient fluid. It is also shown that the inhibitory action of ATP is not dependent on a chelation complex between Ca2+ or Mg2+. Adenosine diphosphate also produces effects essentially the same as ATP whereas 5'-adenosine monophosphate and adenosine produce relatively little or no change.