ALTERATIONS IN MUSCLE TENSION WITHOUT SIMILAR CHANGES IN ELECTRICAL ACTIVITY IN PATIENTS WITH MYASTHENIA GRAVIS 1

Abstract

Simultaneous isometric tension and action potentials were recorded from the belly of the adductor pollicis muscle, which was induced to contract by supramaximal stimulation of the ulnar nerve in 4 patients with myasthenia gravis. Results suggest: (1) Changes in tension reflect more accurately the degree of weakness than changes in electrical activity. (2) In some muscles of some patients with myasthenia gravis weakness may result from a delect in contractile ability apart from or in addition to a defect in neuromuscular transmission. (3) Neo-stigmine may be useful in some patients with myasthenia gravis because of its ability to alter contractile processes of the muscle apart from or in addition to decreasing neuromuscular block. (4) The muscle should not be neglected in studies designed to elucidate the patho-physiology of myasthenia gravis or to obtain better therapeutic agents in this disorder.