S. DURAIRAJ
Abstract
K. Mg1+-ATPase and Ca2+ - ATPase activities in the brain regions such as cerebral hemispheres, (hen imesencephalon, cerebellum and medulla oblongata of fish Oreochromis mocsombicus exposed to organophosphate pesticides such as quinalphos, phenthoate and their combination for 961i showed significant inhibition. In quinalphos exposure, more than 60% inhibition of Na* K+ ATPase activity was found in the brain regions except in the medulla oblongata. Me ATPase and Ca' - ATPase were also inhibited sgnificantly in the brain regions woinalphos. phenthoate and their combination. However, the per cent inhibition of Ca2+ Al rase activity was lesser than the other two enzymes whereas the combination of pesticides produced greater inhibition of three ATPases in the brain regions. KEY WORDS : ATPases, fish, brain regions, OP pesticides.