Evaluation of the protective effects of atropine and diazepam against cypermethrin induced lethality

Abstract

The protective effects of atropine and diazepam against cypermethrin induced lethality were evaluated in mice. Diazepam was used clinically to control convulsion induced by toxic dose of cypermethrin. It was found that diazepam delayed the onset of death induced by cypermethrin but not AZCORD R. Diazepam 5 mg/kg can reduce the mortality induced by both cypermethrin and AZCORD R only 15-20%, and increasing the dose of diazepam does not produce more reduction in lethality. Atropine can significantly delay the onset of death induced by cypermethrin but not by AZCORD (R) or monocrotophos. Low doses of atropine given 30 minutes before the administration of pesticides are very effective in reducing the percent lethality induced by cypermethrin, AZCORD (R) and monocrotophos. The protective effect of atropine suggested that the toxidc effects of cypermethrin are related to acetylcholine. Overactivity of muscarinic cholinergic function can be the consequence of increased acetylcholine relase and/or inhibition of the cholinesterase activity. In this study, cypermethrin didnot inhibit serum cholinesterase and red blood cell acetylcholinesterase. It is likely that the cholinergic muscarinic overactivity is the result of stimulation of ACh release as reported by the other group of investigators. The results of our study suggested that peripheral muscarinic overstimulation was the major cause of death of cypermethrin-induced lethality in mice. The addition of diazepam did not produce additive protective effect.