The effect of general anesthetic agents, ouabain, and aldosterone on striated muscle contraction in toad

Na+ and K+ transport, resting potentials, action potentials, and muscle contraction are interrelated in the excitation-contraction coupling process. Since anesthetics affect the electrogenic Na+ transport mechanism in the toad bladder model and the coupled Na+, K+ transport in muscle, the authors tested the hypothesis that the effects of inhalation anesthetics on ion transport and muscle contraction are parallel. In this study, the effects were assessed of 4 inhalation anesthetics and, for comparison, the effects of ouabain and aldosterone, on contractions of toad sartorius muscle. Cyclopropane, N2O, ether, and halothane, as well as ouabain and aldosterone, increased twitch height in low concentrations. Halothane, ether, and ouabain decreased twitch height in high concentrations. The effect of cyclopropane and N2O, oubain, and aldosterone on muscle contraction closely paralleled their action on electrogenic Na+ transport. This observation supports the hypothesis that the influence of these agents on muscle contraction is linked to the effect on active ion transport or that both effects are equally sensitive to anesthetic agents.