Concentrations of nicotine and metabolites in plasma during active and placebo cigarette scans.

<p>Mean ± standard deviation (ng/mL) of individual subjects' means across 2–75 min, except for the second nicotine row representing nicotine concentrations only from 2–10 min.</p><p>Limits of quantification were 1 ng/mL for cotinine, OH-cotinine and norcotinine, and 2.5 ng/mL for nicotine at individual time point.</p><p>* Active cigarette scan values > placebo cigarette scan value at p<0.01; paired t-test.</p>#<p>Smoker > nonsmoker at p<0.00001; t-test.</p><p>Concentrations of nicotine and metabolites in plasma during active and placebo cigarette scans.</p

Line plots of mean concentrations across subjects of nicotine in plasma versus time of active and placebo cigarette scans.

<p>PET data acquisition began between 5 and 10 min on the time axis in individual subjects.</p

Clusters of Δ[¹¹C]carfentanil BP_ND (placebo - active) to ΔVAS (active - placebo) correlation.

<p>Significance criteria: p<0.001, uncorrected and volume >0.4 mL.</p><p>Percentages in the last column indicate anatomical constituents of clusters.</p><p>Clusters of Δ[¹¹C]carfentanil BP_ND (placebo - active) to ΔVAS (active - placebo) correlation.</p

Positive correlation clusters of Δ[¹¹C]carfentanil binding potential (BP_ND) (placebo - active) versus ΔVAS of feel the effect category in smokers, displayed on trans-axial images of a gray-matter probability maps.

<p>Scatter plots of cluster Δ[¹¹C]carfentanil BP_ND values to ΔVAS are shown together with regression lines. VAS stands for the visual analog scale of smoking effects, and <i>R²</i> stands for the coefficient of determination of linear regression.</p

Correlation clusters of [¹¹C]carfentanil binding potential (BP_ND) of placebo-cigarette scans versus the Fagerström Test for Nicotine Dependence (FTND) in smokers, displayed on trans-axial images of a gray-matter probability maps.

<p>Right panels show scatter plots using cluster [¹¹C]carfentanil BP_ND, together with regression line. In regression equations, <i>R²</i> stands for the coefficient of determination.</p