Effects of carbofuran, diuron, and nicosulfuron on acetylcholinesterase activity in goldfish (Carassius auratus)

Juvenile goldfish (Carassius auratus) were exposed to three widely used pes ticides; carbofuran, diuron, and nicosulfuron. Acetylcholinesterase (AChE) activity and molecular forms of AChE were first characterized in brain and skeletal muscle of unexposed fish. Skeletal muscle had higher AChE activity than brain (306 and 215 nmol/min/mg protein, respectively). In brain, four molecular forms of AChE mere found: A12, G4, G2, and G1. In the muscle, th ree molecular forms were found A12, A8, and G2, AChE activity was then eval uated in both tissues of fish exposed to different concentration of pestici des (5, 50, and 500 mug/L) for 6, 12, 24, and 48 h. In brain, AChE activity was significantly inhibited during all the periods of exposure in response to 50 mug/L (19-28%) and 500 mug/L (85-87%) carbofuran, Such effect was ob served in the muscle only at 500 mug/L (86-92%). Carbofuran had no effect o n the distribution of molecular forms. Significant inhibitions (9-12%) of b rain AChE activity were also observed in response to diuron and nicosulfuro n at 500 mug/L during all periods of exposure and for 50 mug/L nicosulfuron after 24 and 48 h. This study pointed out short-term effects of exposure t o sublethal concentrations of the three pesticides, ranging among different chemical families, on brain and muscle AChE in goldfish. (C) 2000 Academic Press.