CONTINUAL DETERMINATION OF ACETYLCHOLINESTERASE INHIBITION FOLLOWING ORGANOPHOSPHATE POISONING USING AN AUTO ANALYZER

  • 1 January 1977
    • journal article
    • research article
    • Vol. 36  (2) , 231-236
Abstract
A modification for continual monitoring of the blood acetylcholinesterase activity in the rat on an autoanalyzer system was described. Using this technique, inhibition of the enzyme in vitro with O-ethyl-S-(2-dimethylaminoethyl)-methylphosphonothioate was determined. Bimolecular rate constant and I50 [50% inhibition] values were 1.66 .cntdot. 106 M-1 .cntdot. min-1 and 1.4 .cntdot. 10-8 M, respectively. Rats treated i.m. with 0.043 mg/kg of this compound showed fast and rapid inhibition of the blood acetylcholinesterase after intoxication. The bimolecular rate constant of inhibition in vivo, calculated analogously as that in vitro, was 1.37 .cntdot. 106 M-1 .cntdot. min-1. On the presumption that both rates of inhibition (in vitro and in vivo) are identical, the concentration of organophosphate producing inhibition effect in vivo was 82% of the dose administered.