ABSTRACT
The present study was undertaken to identify the nature of the interactive effects of chlorpyrifos (CPF) and cold stress (15° and 20°C) on the activities of acetyl cholinesterase (AChE), choline acetyl transferase (ChAT), Na+, K+-ATPase and malondialdehyde (MDA) level in the cerebral cortex of 1 week, 3 weeks and 3 months of age. The results indicated an interaction of CPF with age of animal and cold exposure resulting in marked decrease in the activity levels of AChE, ChAT, Na+, K+-ATPase, followed by increased MDA levels. Overall, the effects of co-exposure of cold stress and CPF were appreciably different from either of the exposures. However, synergistic-action of CPF and cold stress at 15°C showed a greater inhibition of AChE, ChAT, and Na+, K+-ATPase in comparison with CPF or cold stress alone and together at 20°C. The results reveal that young animals are markedly more sensitive to interactive effects of CPF and cold stress than adults.