Biochemical and histological changes in the brain tissue of spotted murrel, Channa punctatus (Bloch), exposed to endosulfan.

The present experiment was conducted to establish the relationship between selected physiological parameters and histological responses of Channa punctatus brain tissue to endosulfan exposure. The fish (35.6 +/- 0.7 g) was exposed to sublethal endosulfan concentration (8.1 microg l(-1)) for a period of 12, 24, 36, 48, 72, and 96 h. Results showed that brain glucose level increased significantly after exposure, indicating a hyperglycemic state of the fish. Brain vitamin C level decreased with an increase in the exposure time. Acetylcholine esterase and adenosine triphosphatase enzyme activities also showed a significant reduction upon endosulfan exposure. Brain histopathology after 96 h endosulfan exposure showed that the apical lobe of the cerebrum (the only portion examined) had mild necrosis. Focal area of gliosis could be seen in the cerebrum, which were absent in the control fish. The results indicate that exposure of sublethal concentration of endosulfan to C. punctatus may have a direct effect on the histology of the fish's brain tissue, thereby affecting its metabolism.