Adenosine 3’–5’ Cyclic Monophosphate (cAMP)-Induced Changes in Intracellular Ionic Activities: Relation to Epithelial Ion Transport

Abstract

Ion-selective microelectrodes have been used successfully to measure steady-state intracellular ion activities in a variety of cells. In recent years, the development of liquid ion-exchanger microelectrodes that are easily constructed, have rapid response times, and are highly selective for individual ions of physiological importance, e.g. K+, Na+, Ca2+, Cl-, has opened up the possibility of investigating changes in intracellular activity that accompany or may be responsible for such cellular events as: excitation, contraction, secretion, and the action of specific hormones. This report describes a study currently under way in our laboratory in which the measurement of intracellular ionic activities is being used to obtain insights into the mechanism or mechanisms by which adenosine 3’-5’ cyclic monophosphate (c-AMP) regulates ionic transfer processes in the small intestine.