Effects of carbamates on whole blood cholinesterase activity: chemical protection against soman

• Published in: Drug and chemical toxicology (New York, N.Y. 1978) Vol. 3; no. 3; p. 319
• Main Authors: Heyl, W C, Harris, L W, Stitcher, D L
• Format: Journal Article
• Language: English
• Published: United States 1980
• Subjects: Animals; Carbamates - pharmacology; Carbamates - toxicity; Cholinesterases - blood; Lethal Dose 50; Male; Organophosphorus Compounds - antagonists & inhibitors; Pyridostigmine Bromide - pharmacology; Rabbits; Soman - antagonists & inhibitors; Soman - toxicity
• ISSN: 0148-0545
• DOI: 10.3109/01480548009002226

The toxicity (LD50) of several carbamates, all reversible inhibitors of cholinesterase (ChE), were determined in male rabbits. These include isopropyl methylphenyl carbamate (IMPC), pyridostigmine, neostigmine, benzpyrinium and physostigmine. When 1/9 of the LD50 of the above carbamates was individually combined with atropine (A) and benactyzine (B), mecamylamine (M) or chloropromazine (CPZ) and administered to rabbits in a pretreatment regimen, most animals could be protected from a 10 LD50 challenge of Soman. If CPZ, M or B was omitted from this regimen, no rabbits survived this challenge of Soman. The protection afforded against Soman was found to be related to reversible inhibition of ChE by the carbamates; reversible ChE inhibition varied with the route of injection and with the physical properties of the carbamate. Oral administration of pyridostigmine, a quaternary carbamate, provided protection for 24 hours. When the pretreatment included four components (pyridostigmine, A, M and B), the LD50 of Soman was raised 30.8 times in rabbits.