Effects of a single exposure to chlorphenvinphos, an organophosphate insecticide, on hot-plate behaviour in rats.
Effect of a single i.p. exposure to an organophosphate insecticide, chlorphenvinphos (CVP), in doses of 1.0 and 3.0 mg/kg (one third and one tenth LD50, respectively), on the latency of the paw-lick response (hot plate test) was investigated in rats before and after a short inescapable footshock. The test was repeated twice on the 18th and 19th days after the exposure, i.e. after a time sufficient for a full recovery of cholinesterase activity in the blood and brain. On the first day of testing the groups did not differ with respect to the paw-lick latency before footshock. However, the paw-lick latency after footshock (the index of stress-induced analgesia) was significantly longer in rats exposed to the higher dose of CVP (3.0 mg/kg) than in the control animals. Twenty four hours later, in the control animals, the paw-lick latencies before footshock were shortened in comparison with those recorded on the day before. An opposite effect was observed in the rats exposed to 3.0 mg/kg of CVP. The data suggest that some alterations in the brain functional state may outlast the CVP induced depression of cholinesterase activity.
Gralewicz
S
S
Department of Toxicity Evaluation, Nofer Institute of Occupational Medicine, Lodz, Poland.
Soćko
R
R
D000818:Animals; D001522:Behavior, Animal; D002709:Chlorfenvinphos / Q000008:administration & dosage / Q000494:pharmacology*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D004558:Electric Stimulation; D008297:Male; D010146:Pain / Q000503:physiopathology*; D011897:Random Allocation; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects; D012684:Sensory Thresholds / Q000187:drug effects
D002800:Cholinesterase Inhibitors; D002709:Chlorfenvinphos