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Abstract

In the present investigation, changes in Na+/K+-, Mg2+- and Ca2+-ATPase enzyme activities in different areas of rat brain were examined under the administration of the synthetic opioid analgesic drug tramadol in the absence of induction of pain. Male adult Wistar rats were used as the experimental animals with five groups of six rats each, housed in separate cages. Tramadol was injected subcutaneously into the rats and the changes in enzyme activities in different brain areas were followed at 3, 6, 12 and 24 h following drug administration. The enzyme activities showed a decrease in all areas of the brain following administration of single dose of tramadol and by 24 h they returned more or less to the respective control levels. In the brain of control rats, pons-medulla registered the highest Na+/K+-ATPase activity. Following tramadol administration, maximal decrease was recorded in cortex at 6 h. The Mg2+-ATPase activity in control rats was found to be highest in cortex. On tramadol dosing, maximal decrease was recorded in hypothalamus and cortex. Ca2+-ATPase activity was found to be highest in cortex in the brain of control rats. The activity of this enzyme showed a decrease in all areas of the brain following tramadol administration, with maximal decrease in hippocampus at 3 h. Minor deviations from the respective controls at this period were negligible and not statistically significant. The results indicate that the administration of tramadol during non-induction of pain would induce decrement in the activities of the ATPase enzymes, indicating its impact on energy metabolism and membrane transport functions.