Alteration in the neurotransmitter levels in the brain of the freshwater snakehead fish (Channa punctatus) exposed to carbofuran.

Channa punctatus a freshwater fish exposed to carbofuran (0.6 mg l(-1)) for 15 days exhibited alterations in norepinephrine (NE), dopamine (DA) and serotonin (5-HT) levels. NE levels increased in the cerebellum and decreased in the medulla and cerebral cortex relative to the controls. Increased DA levels were observed in the cerebellum and medulla whereas DA levels decreased in the cerebral cortex relative to the controls. Depletion of 5-HT was noticed in the cerebellum, medulla and cerebral cortex relative to controls. The results suggested an overall decrease in the level of neurotransmitters in the cerebral cortex region of the brain. The neurotoxic effect of carbofuran was not uniform in the brain but was localized to the brain regions which regulate motor activity and behaviour in fish.