Role of carboxylesterase in soman, sarin and tabun poisoning in rats.

TOCP (triorthocresyl phosphate) inhibits carboxylesterase (CarbE) activity in rat plasma and liver and significantly increases soman, sarin and tabun toxicity. Application of these agents after TOCP caused strong additional inhibition of CarbE and cholinesterases (ChE) in rat red blood cells, plasma, liver, brain, diaphragm and intercostal muscle. After phenobarbital pretreatment, which induced CarbE activity in plasma and liver by 80% and that of plasma ChE by 33%, acute toxicity of soman and tabun was greatly decreased, while that of sarin remained unaffected.