[The effect of atropine and diazepam on mammalian neuromuscular junction--a model of their protective action against anticholinesterase-based war and agriculture poisons].

Abstract

The effect of atropine and diazepam on the mammalian neuromuscular junction. Nicotinolytic effect of atropine on the neuromuscular junction is discussed as a main mechanism of the beneficial effect of this drug during war and agriculture poisoning by anticholinesterases. Atropine is beneficial as it reduces the amplitude of intracellularly recorded endplate potentials and, first of all, causes a marked shortening of their time course (Beránek, Vyskocil 1968, Magazanik, Vyskocil 1969). Diazepam effectively blocks trains of action potentials in individual rat diaphragm muscle fibers, apparently by elevating the chloride permeability. It is suggested that similar increase in Cl- permeability may occur in brain excitable structures and can counteract the anticholinesterase-induced prolongation of ACh-depolarization that evokes repetitive firing.