Role of Muscle Fasciculations in the Generation of Myopathies in MammalianSkeletal Muscle

摘要

The myotoxicity of pyridostigmine bromide was investigated on rat diaphragm nerve-muscle preparations in vitro. Within 2 h of exposure to pyridostigmine (2 microns), diaphragm muscles exhibited ultrastructural alterations characterized by swelling of subjunctional mitochondria and disorganization of contractile proteins. These alterations developed both in the absence and presence of electrical stimulation of the phrenic nerve, and were accomplished by continuous muscle fasciculations. Pretreatment by tetrodotoxin suppressed both the muscle fasciculations and the appearance of myopathies. These findings suggest that fasciculations may be an important contributing factor in the development of anticholinesterase-induced myopathies.