ABSENCE OF SUPERSENSITIVITY TO ACETYLCHOLINE IN INNERVATED MUSCLE SUBJECTED TO A PROLONGED PHARMACOLOGIC NERVE BLOCK

¹ Department of Pharmacology, Loyola University Stritch School of Medicine, Maywood, Illinois and Research Service, Veterans Administration Hospital, Hines, Illinois
² Department of Pharmacology, Loyola University Stritch School of Medicine, Maywood; Illinois and Research Service, Veterans Administration Hospital, Hines, Illinois

Prolonged conduction block and continued absence of neuromuscular impulses in skeletal muscle were maintained, up to 14 days, by a lidocaine-silicone polymer implant around the sciatic nerve of rabbits. At no time did supersensitivity to acetylcholine develop, and the threshold dose of acetylcholine remained the same as in normal controls, about 50 µg. In surgically denervated controls with resultant hypersensitivity, this dose is about 0.1 µg. Responses of the lidocaine-blocked muscles to injected succinylcholine and d-tubocurarine were identical with those of normal controls. These findings do not support some current concepts that prolonged absence of neuromuscular impulses, even in absence of denervation, would induce hypersensitivity changes. The results suggest that neuromuscular transmission activity per se may not be essential in the trophic function of the nerve on skeletal muscle.

This article has been cited by other articles:

				S Roper and C. Ko Impulse blockade in frog cardiac ganglion does not resemble partial denervation in changing synaptic organization Science, October 6, 1978; 202(4363): 66 - 68. [Abstract] [PDF]