Cold stress interaction on organophosphate insecticide poisoning: age-related assessment in rat cerebral cortex.

The present study was undertaken to identify the nature of the interactive effects of chlorpyrifos (CPF) and cold stress (15 degrees and 20 degrees 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 degrees C showed a greater inhibition of AChE, ChAT, and Na+, K(+)-ATPase in comparison with CPF or cold stress alone and together at 20 degrees C. The results reveal that young animals are markedly more sensitive to interactive effects of CPF and cold stress than adults.