摘要：Behavioral sensitization, as evidenced by the progressive enhanced locomotor response to a subsequent injection of the drug, is the major behavioral outcome produced by repeated injections of nicotine, and a model for studying drug addiction. It is putatively regarded that the alteration of extracellular dopamine release in the nucleus accumbens is closely associated with nicotine-induced behavioral sensitization. The present study was performed to evaluate the effects of the essential oil from Angelica gigas N AKAI (on fragrance inhalation) on repeated nicotine-induced locomotor activity and extracellular dopamine levels in the nucleus accumbens of rats using in vivo microdialysis. Rats were given repeated injections of saline or nicotine (0.4 mg/kg s.c., twice a day for 7 d), followed by one challenge injection on the 4th day after the last daily injection. Systemic challenge with nicotine (0.4 mg/kg s.c.) produced a larger increase in locomotor activity in nicotine-pretreated rats than in saline-pretreated rats. A direct local challenge of 3 m M nicotine via a microdialysis probe also induced a larger increase in dopamine release in nicotine-pretreated rats than in saline-pretreated rats. Most importantly, our results showed that inhalation of the essential oils from Angelica gigas N AKAI significantly decreased both dopamine release in the nucleus accumbens and locomotor activity induced by a nicotine challenge. These results suggest that the essential oils from Angelica gigas N AKAI inhibit nicotine-induced behavioral and neurochemical sensitization, and imply that the essential oil from Angelica gigas N AKAI may be effective in treating nicotine addiction, possibly by modulating dopamine release in the nucleus accumbens.
