IN VIVO INHIBITION AND RECOVERY OF BRAIN ACETYLCHOLINES TERASE IN TOPMOUTH GUDGEON (PSEUDORASOBORA PARVA) FOLLOWING EXPOSURE TO FENITROTHION

Freshwater fish, topmouth gudgeon (%Pseudorasobora parva%), were pretreated with piperronyl butoxide (PBO) or triphenyl phosphate (TPP) and then exposed to different concentrations of fenitrothion (FNT) in a static system. Evaluation of brain acetylcholinesterase (AchE) activity after 24, 48 and 96 h pesticide exposure indicated that AchE activity decreased as the concentration increased. Fish pretreated with TPP exhibited significantly decreased AchE activity whilst in the PBO pretreated group, increased activity was observed as compared with those exposed to FNT alone. The pattern of AchE recovery was also assessed in fish previously exposed for 96h and then transferred to clean (chemical free) water. Following 8 days of recovery period, the AchE activity of those exposed to FNT alone and pretreated with TPP was still lower than that of the control. This study showed that FNT may cause hazard to fish after field application.