1. ¹UCLA Department of Psychiatry and Biobehavioral Sciences, Los Angeles, CA, USA
2. ²Greater Los Angeles VA Healthcare System Positron Emission Tomography Center, Los Angeles, CA, USA
3. ³UCI Department of Physics, Irvine, CA, USA
4. ⁴UCSD Department of Psychiatry, San Diego, CA, USA
5. ⁵UCLA Department of Molecular and Medical Pharmacology, Los Angeles, CA, USA

Correspondence: Dr AL Brody, UCLA Department of Psychiatry & Biobehavioral Sciences, 300 UCLA Medical Plaza, Suite 2200, Los Angeles, CA 90095, USA. Tel: +310 268 4778; Fax: +310 206 2802; E-mail: abrody@ucla.edu

Received 6 March 2008; Revised 9 May 2008; Accepted 10 May 2008; Published online 18 June 2008.

Abstract

Prior studies have demonstrated that both nicotine administration and cigarette smoking lead to dopamine (DA) release in the ventral striatum/nucleus accumbens. In tobacco-dependent individuals, smoking denicotinized cigarettes leads to reduced craving, but less pleasure, than smoking regular cigarettes. Using denicotinized cigarettes and ¹¹C-raclopride positron emission tomography (PET) scanning, we sought to determine if nicotine is necessary for smoking-induced DA release. Sixty-two tobacco-dependent smokers underwent ¹¹C-raclopride PET scanning, during which they smoked either a regular or denicotinized cigarette (double-blind). Change in ¹¹C-raclopride binding potential (BP) in the ventral striatum from before to after smoking was determined as an indirect measure of DA release. Cigarette craving, anxiety, and mood were monitored during scanning. Smoking a regular cigarette resulted in a significantly greater mean reduction in ventral striatal ¹¹C-raclopride BP than smoking a denicotinized cigarette. Although both groups had reductions in craving and anxiety with smoking, the regular cigarette group had a greater improvement in mood. For the total group, change in BP correlated inversely with change in mood, indicating that greater smoking-induced DA release was associated with more smoking-related mood improvement. Thus, nicotine delivered through cigarette smoking appears to be important for ventral striatal DA release. Study findings also suggest that mood improvement from smoking is specifically related to ventral striatal DA release.