The mode of recovery of cholinesterase activity in vivo after organophosphorus poisoning. 2. Brain cholinesterase

Abstract

Recovery of tetraethyl pyrophos-phate- or dimethyl p-nitrophenyl phosphate-inhibited rat-brain true cholinesterase in vivo occurred in 2 stages, a rapid partial recovery being followed by a slower, and probably exponential, return to normal activity. With diisopropyl phosphorofluoridate- or isopropyl methyl-phosphonofluoridate-inhibited rat-brain true cholinesterase only 1 stage was observed in the recovery in vivo which occurred throughout at an exponential rate. The 1st stage in the recovery is explained in terms of spontaneous reactivation and aging of the inhibited enzyme, and the 2d stage is correlated with new enzyme synthesis associated with the normal turnover of brain protein.