Transdermal nicotine increases plasma nitric oxide in dogs

Nicotine is the major addictive component of cigarette smoke and nicotine-replacement (by patches or gum) is used to treat nicotine-dependence, i.e. smoking cessation. However, the physiologic consequences of nicotine treatment independent of smoking are unknown. Experiments were performed to determine effects of transdermal nicotine on plasma nitric oxide. Transdermal nicotine patches (either 11 or 44 mg/day) were applied daily for 5 weeks to the shaved necks of male mongrel dogs. Oxidative products of nitric oxide (NO_x) were measured by chemiluminescence in plasma weekly at 6 and 24 hours after placement of patches, times which correspond to peak and nadir concentrations of nicotine, respectively. Plasma NO, averaged 9.2 ± 0.5 nmoles/ml (n=6) prior to placement of nicotine patches. Plasma NO, increased significantly (33%) six hours after placement of the patches and decreased to baseline levels at 24 hours. There were no differences in peak plasma NO, between dogs treated with the 11 or 44 mg patches. Neither were there differences in peak plasma NO_x at 2, 3, 4 or 5 weeks of nicotine treatment. These results suggest that nicotine-replacement by patches increases plasma NO_x in a time pattern corresponding to nicotine-plasma concentrations. Further, increases in plasma NO, do not seem to correspond to the dose or duration (up to 5 weeks) of patch-treatment.