Intracellular Electromyography

Abstract

IN THE STUDY of human muscle pathology the nature of possible pathophysiological disorders of the muscle cell has been inferred from clinical, biochemical, and conventional (extracellular) electromyographic evidence. Intracellular (IC) recording with glass microelectrodes offers the possibility of studying the muscle cell directly. This can be done without exposing the muscle and thus resting membrane potentials (RMP) in normal human muscle and in several pathological conditions have been measured.^1-4 Most data upon activity in human muscle fibers derive from in vitro studies of normal and pathological biopsy material, especially the intercostal muscle preparation.^5-8 The in vivo study of the action potential has proved more difficult largely due to the inability to maintain the microelectrode's IC location during stimulation, although action potentials evoked by current passed through the recording micropipette have been reported.^1,4 By this method it is possible to obviate the movement occasioned by voluntary contraction