Biol. Pharm. Bull., 28(12),2323-2326, December 2005

Notes

The Essential Oil from Angelica gigas NAKAI Suppresses Nicotine Sensitization

Rong Jie ZHAO,^a Byung Soo KOO,^b Geun Woo KIM,^b Eun Young JANG,^a Jong Rok LEE,^a Mi Ryeo KIM,^a,c Sang Chan KIM,^a,c Young Kyu KWON,^c Kwang Joong KIM,^c Tae-lin HUH,^d Dae-Hyun KIM,^e Insop SHIM,^f and Chae Ha YANG^*,a,c

^a The Research Center for Biomedical Resources of Oriental Medicine, Daegu Haany University; Daegu 706-828, Korea: ^b College of Oriental Medicine, Dongguk University; Gyeongju 780-714, Korea: ^c College of Oriental Medicine, Daegu Haany University; Daegu 706-628, Korea: ^d TG Biotech Co. Ltd. Techno Building, Kyungpook National University; Daegu 702-832, Korea: ^e School of Medicine, Keimyung University; Daegu 700-712, Korea: and ^f College of Medicine, The Catholic University of Korea; Seoul 137-701, Korea. * To whom correspondence should be addressed. e-mail: chyang@dhu.ac.kr

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 NAKAI (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 mM 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 NAKAI 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 NAKAI inhibit nicotine-induced behavioral and neurochemical sensitization, and imply that the essential oil from Angelica gigas NAKAI may be effective in treating nicotine addiction, possibly by modulating dopamine release in the nucleus accumbens.

Key words Angelica gigas; nicotine; dopamine; essential oil; locomotor activity; aromatherapy