The inhibition of brain acetylcholinesterase activity of juvenile largemouth bass Micropterus salmoides by sublethal concentrations of diazinon.

An effect of diazinon on brain acetylcholinesterase (AChE) activity of juvenile largemouth bass Micropterus salmoides was observed. The exposure concentration started from 1/10 of the 24-h LC50 value, 90 micrograms/liter. The exposure duration was 24 h. Statistically significant and dose-dependent reductions in the mean AChE activities we seen at 90, 180, 270, 360, and 450 micrograms/liter. The results show that juvenile brain acetylcholinesterase activities were significantly inhibited by sublethal doses of diazinon. Inhibition of brain AChE will definitely cause physiological and behavioral modifications that reduce survival ability of the animals at an early stage of growth.