Effect of piracetam and vitamin E on phosphamidon-induced impairment of memory and oxidative stress in rats.

ABSTRACT

Organophosphate pesticides, such as phosphamidon (PHOS), have been shown to adversely affect memory and induce oxidative stress after both acute and chronic exposure. The present study was therefore designed to investigate the effects of piracetam (PIR) and vitamin E on PHOS-induced modulation of cognitive function and oxidative stress in rats. Cognitive function was assessed using step-down latency (SDL) on a passive avoidance apparatus and transfer latency (TL) on an elevated plus maze. Oxidative stress was assessed by examining the levels of malondialdehyde (MDA) and nonprotein thiols (NP-SH) in isolated homogenized whole brain samples. The results showed a significant reduction in SDL and a prolongation of TL in the PHOS (1.74 mg/kg/day per oral; p.o.)-treated group at weeks 6 and 8, as compared to the control group. Administration of PIR (600 mg/kg/day p.o.) or vitamin E (125 mg/kg/day p.o.) for 2 weeks antagonized the effect of PHOS on SDL as well as TL. PHOS per se produced a significant increase in brain MDA levels and a decrease in brain NP-SH levels, whereas administration of PIR (600 mg/kg/day p.o.) or vitamin E (125 mg/kg/day p.o.) attenuated these effects. Thus, the results of the study showed that both PIR and vitamin E attenuated the cognitive dysfunction and oxidative stress induced by PHOS in the rat brain.