The Use of Acetyl Thiocholine in the Histochemical Study of the Action of Organophosphorus Insecticides12

Abstract

Acetyl thiocholine and related thioesters were investigated as histochemical indicators of cholinesterases in insects. It was shown that acetyl thiocholine was hydrolyzed by insect cholinesterase in a manner indistinguishable from acetyl choline. The histochemical detection of copper thiocholine was used to demonstrate that the intact insect nerve sheath effectively prevents the penetration of acetyl thiocholine into the ventral nerve cord of Periplaneta americana and that cholinesterase activity in this substrate is abolished by lethal doses of organophosphorus insecticides.