Intravenous nicotine reduces cerebral glucose metabolism: A preliminary study

Nicotine is self-administered by smoking tobacco products, and enhances positive mood (at least in smokers). Since most drugs of abuse decrease regionalcerebralmetabolic rate(s) forglucose (rCMRglc) in human subjects, we posited that administration of nicotine wouldsimilarly reduce rCMRglc. Positron emission tomography (PET) with [F-18]fluorodeoxyglucose was used to assess the effects ofintravenous nicotine (1.5 mg) on cerebralglucose metabolism in six healthy male volunteers (21-38 years of age). Two PET assays(placebo and nicotine) were performed, and subjective self-reports of mood and feeling state were collected. Data were analyzed usinganalysis of variance. Nicotine reduced globalglucose metabolism (by 9.51% of placebo control), with reductions in most of the 30individualregions tested. Nine regions had bilateraleffects that reached statisticalsignificance (p<0.05, uncorrected forthe number ofregions tested), although the statisticalmodelused did not separate these effects from a global effect. The subjects reported bothpositive and negative effects of nicotine on mood/feeling state. The widespread decreases in cerebralmetabolism are consistent with themany effects of nicotine on cognition and mood. The findings indicate that nicotine resembles other drugs of abuse in reducing brainmetabolism, perhaps by a common mechanism.