A regional technique for the study of sensitivity to curare in human muscle

A regional technique for the study of curare sensitivity of human muslce in vivo is described. 0-5 mg d-tubocurarine is given intravenously at the wrist while the circulation to the hand and forearm is occluded. Neuromuscular transsmission is then studied by delivering trains of stimuli to the ulnar nerve and recording changes in evoked muscle action potential (map) amplitude from the abductor digiti minimi. In most normal subjects, this dose causes a recognizable block in neuromuscular transmission. The amplitude of a single evoked MAP is depressed and declines further during trains of 3/s repetitive stimulation. Recovery usually takes place gradually during the 20-30 minutes after the release of the tourniquet. The technique will be of value in the study of latent disturbance of neuromuscular transmission in neurological and metabolic disorders.