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Abstract

The effects of oral administration of aspirin and paracetamol on plasma and brain protein, tryptophan concentrations and monoamine oxidase activity were investigated. Fifty-four virgin albino Sprague-Dawley rats were used for the study and divided into three groups. The first group of rats was fed rat chow with water ad libitum and oral administration of 0.05% (w/v) aspirin and the second group of rats was fed rat chow with water, ad libitum and oral administration of 0.05% (w/v) paracetamol for 35 days. The third group of rats serves as the control and fed with rat chow and water ad libitum for 35 days. The rats were sacrificed by decapitation after starving them overnight and their blood and brain were collected quickly. Plasma and brain protein and tryptophan concentrations and brain monoamine oxidase activity were assayed. Results showed that oral administration of aspirin and paracetamol do not significantly (p< 0.01) affect body weight, feed and water intake of rats. But these drugs significantly elevated plasma protein, tryptophan and decreased brain protein and tryptophan concentrations. Oral administration of aspirin significantly inhibited brain monoamine oxidase activity, but was not affected by paracetamol. Data of the present study indicate that aspirin, but not paracetamol could alter the metabolism and neurotransmission mediated by certain biogenic amines catalyzed by monoamine oxidase in the brain.