Effects of myotoxins on skeletal muscle fibers.

This review highlights various aspects of a number of experimental myological alterations, induced by different chemical toxicants, including anticholinesterase, colchicine, vincristine, chloroquine, tetanus toxin, botulinum toxin, reserpine and emetine. Despite their chemical diversity and mechanism(s) of action, it is evident from the data discussed here that remarkably different toxic agents exert quite similar effects and induce toxic myopathies. The latter include preferential involvement of slow-twitch red muscle, mitochondrial derangement, denervation-like alterations, formation of membranous whorls, tubular aggregates, autophagic vacuoles and axonal sprouts. The non-invasive experimental models discussed here are valuable in studying various aspects of myopathology in the absence of any mechanical damage to the innervating elements from neurons to axonal terminals.