Transmembrane potentials and fluxes in isolated rabbit atria

Abstract

Data are presented from a study of transmembrane potentials and unidirectional fluxes of K⁴² under identical conditions in isolated rabbit atria. The effects of acetylcholine and varying extracellular concentrations of Na, K and Ca were investigated. Particular emphasis has been placed on the role of Ca and on the terminal phase of repolarization of the action potential, namely the negative after potential. Data are given which support the contention that the duration of the negative after potential depends on an active transport of K or Na, or both.