Electromyographic Findings in Experimental Botulinum Intoxication

Abstract

Abstract J osefsson J.‐O. and S. T hesleff . Electromyographic findings in experimental botulinum intoxication. The electrical activity of botulinum intoxicated skeletal muscle was examined in the rabbit by the use of electromyography. 5 to 6 days after an intramuscular injection of the toxin, fibrillation potentials appeared and persisted for a period of at least 60 days. The potentials were similar in amplitude and time course to those recorded following motor nerve degeneration. Botulinum toxin, however, is known not to affect the morphological structure of the motor nerve and its terminals. Its sole action is to block transmitter release selectively from cholinergic nerve endings. Our results therefore suggest that in nerve degeneration lack of transmitter release is primarily responsible for initiating the process which produces the electromyographic pattern typical of denervation.