Table 2. Concentrations of nicotine and metabolites in plasma during active and placebo cigarette scans.

Variables	Smokers		Nonsmokers
Cigarette type for PET Sessions	Placebo	Active	Placebo	Active
Nicotine (ng/mL)	1.9±0.9#	4.4±1.4* #	0.1±0.1	0.7±0.7
Nicotine (2–10 min; ng/mL)	1.9±1.2#	5.8±1.9* #	0.2±0.4	0.9±0.9
Cotinine (ng/mL)	217±106	230±97	<1	<1
Trans-3-hydroxy-cotinine (ng/mL)	70.5±38.7	63.6±38.6	0	0
Norcotinine (ng/mL)	2.6±2.3	3.2±1.9	0	0

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.

Limits of quantification were 1 ng/mL for cotinine, OH-cotinine and norcotinine, and 2.5 ng/mL for nicotine at individual time point.

* Active cigarette scan values > placebo cigarette scan value at p<0.01; paired t-test.

^#Smoker > nonsmoker at p<0.00001; t-test.