The effect of hemorrhagic shock on intracellular muscle action potentials in the primate

Techniques developed for the in vivo study of cellular physiology have been applied to hemorrhagic shock in primates. A technique of measuring skeletal muscle transmembrane resting and action potentials was correlated with an analysis of fluid and electrolytes in skeletal muscle and extracellular fluid. The data obtained indicate a marked diminution in muscle extracellular water and an increase in intracellular sodium and water during shock. There was an associated decrease in resting membrane potential, a decrease in amplitude of the action potential, and prolongation of both the repolarization and depolarization time. In addition, there was a decrease of muscle intracellular potassium concentration during shock. Resuscitation reversed these changes acutely except for repolarization time which remained prolonged with a persistent depression of measured intracellular sodium combined with an expanded ECW. This study confirms alterations in cellular membranes in vivo during hemorrhagic shock. Further studies are in progress to delineate the precise changes in cellular transport mechanisms.