Passion flower extract antagonizes the expression of nicotine locomotor sensitization in rats

Abstract

Context: Nicotine, a bioactive component of tobacco, is highly addictive. Numerous therapies have been developed or are currently under investigation for smoking cessation, and all have met with limited success and/or side effects, indicating the need for additional therapies.Objective: This study examines the ability of a commerically-available aqueous extract of Passiflora incarnata Linn. (Passifloraceae) to ameliorate the signs of nicotine sensitization using a rat model.Materials and methods: Rats were administered 0.4 mg/kg nicotine or vehicle once a day for four consecutive days. Nicotine adminstration produces sensitization of locomotor activity, a phenomenon implicated in the development of nicotine dependence. On the fifth day, locomotor activity of the subjects was monitored as rats from each treatment group were administered 800 mg/kg of Passiflora incarnata extract (or its vehicle) followed by a challenge dose of 0.4 mg/kg nicotine.Results: When given to rats sensitized to nicotine for 4 days, the challenge dose of nicotine increased locomotor activity by more than 2-fold over activity following nicotine challenge in rats treated with vehicle during the sensitization phase. The difference was significant from 15–40 min after nicotine administration. Rats sensitized to nicotine then treated with Passiflora incarnata extract prior to the nicotine challenge exhibited a level of locomotor activity the same as the vehicle-treated controls.Discussion: Passiflora incarnata extract did antagonize the expression of nicotine locomotor sensitization.Conclusion: Passiflora incarnata extract should be examined in future studies to evaluate its potential for treating nicotine addiction in humans.