The mode of recovery of cholinesterase activity in vivo after organophosphorus poisoning. 1. Erythrocyte cholinesterase

Abstract

Recovery of sheep-erythrocyte cholinesterase inhibited in vivo by dimethyl p-nitrophenyl phosphate, tetraethyl pyrophosphate or isopropyl methylphosphonofluoridate occurred in 2 stages, a rapid partial recovery being followed by a slower linear return to normal activity. With diisopropyl phosphorofluoridate-inhibited erythrocyte cholinesterase, recovery occurred throughout at the slower linear rate. During the 1st stage in the recovery spontaneous hydrolysis and aging of the inhibited cholinesterase occurred simultaneously; the absolute rates of these 2 processes determined the speed of recovery and their relative rates determined the extent of recovery. The characteristics of this stage varied with the inhibitgr used. The 2d stage in the recovery was correlated with new red-cell formation and the rate of recovery in this stage, 0.5-0.7% per day, was independent of the inhibitor used.