Sensitivity of brain cholinesterase to cypermethrin toxicity in freshwater teleost Tilapia mossambica.

Cypermethrin at sublethal concentrations induced significant changes in acetylcholinesterase (AChE) activity and acetylcholine (ACh) content in the brain tissue of both juvenile and adult-fish. Maximum inhibition of AChE activity is noticed at 6h and 12h after exposure to cypermethrin in juvenile and adult fish respectively. In contrast, the ACh levels registered an elevation in both the cases. During subsequent periods the rate of recovery in AChE activity and ACh content is variable in both the groups.