The Effect of Ethanol Extract of Aerial Parts of the Mentha piperita in the Acquisition, Tolerance Expression and Dependence to Morphine in Adult Male Mice

Morphine dependence is a compulsive pattern of drug taking, resulting from the positive reinforcement of the rewarding effects of drug taking and the negative reinforcement of withdrawal syndrome that accompanies the cessation of drug taking. The objective of this study was to investigate the effect of ethanol extract of aerial parts of the Mentha piperita in the acquisition, tolerance expression and dependence to morphine in adult male mice In the present study, 75 NMRI mice were divided into fifiteen groups. The Hot plate test was used to survey the morphine activity. Morphine was injected (2.5, 5, 10, 20, 40 mg/kg, i.p.) twice daily for seven days, except in 8th day in which morphine was administrated at a single dose (50 mg/kg). The extract (50, 75, 100 mg/kg) was injected for eight days. The control animals were intact, and sham animals only received morphine. Naloxone was injected (10 mg/kg) five hours after the final dose of morphine and the withdrawal signs were recorded during a 30 minute period. The data were expressed as mean values ± SEM and tested, using analysis of one-way ANOVA test. Peppermint extract at doses of 75 and 100 kg significantly improved the tolerance expression and dependence to morphine in animals and significantly reduced the symptoms of withdrawal. Peppermint extract was commuted morphine tolerance and dependence in mice.The plant contained component(s) that alleviate morphine withdrawal syndrome. The extract possibly is effective in improving tolerance to morphine.