Electrophysiological Effects of Ca Ionophore A23187 on Frog Stomach

Abstract

Summary

The Ca ionophore A23187 at a concentration of 10⁻⁶ M in a Cl⁻ nutrient solution containing 1 mM Ca²⁺ or at a concentration of 10⁻⁵ M in a Cl⁻ nutrient solution containing 0.04, 1 or 3 mM Ca²⁺ decreased the resistance and increased the H⁺ secretory rate of the frog gastric mucosa of Rana pipiens. Similar effects were obtained with 10⁻⁵ M ionophore in secretory solutions. The ionophore exhibited inhibitory effects in Cl⁻-free media. These results together with those involving Ca²⁺-free Cl⁻ solutions and Ba²⁺ studies suggested that the ionophore increased Cl⁻ conductance, particularly of the secretory membrane.