PROTECTION OF ORGANOPHOSPHATE-INACTIVATED ESTERASES WITH PHOSPHOTRIESTERASE

The protective effect of phosphotriesterase (PTE) on cholinesterase (C hE) and carboxylesterase (CaE) activities was studied in mice. The PTE pretreatment (120 U/g body wt, 9.6 mu g/g body wt) given iv 10 min be fore diisopropyl fluorophosphate, sarin, or soman variably prevented C hE inhibition in erythrocytes and plasma and CaE in plasma. PTE also p rotected the brain and lung ChEs against inactivation by organophospha tes (OPs). The recovery of the enzymes was dependent on the OP used. P ostexposure therapy with PTE, given 1.5 hr after paraoxon, also preven ted ChE inhibition in erythrocytes, brain, and lung 24 hr after exposu re. The distribution studies with [I-125]PTE showed that PTE does not markedly gain access into the central nervous system. (C) 1996 Society of Toxicology