Plasma nitric oxide before and after smoking cessation with nicotine nasal spray.

Nicotine may affect cardiovascular function through release of neurotransmitters from autonomic nerves or release of vasoactive substances from the vascular endothelium. Nitric oxide is a neurotransmitter and endothelium-derived factor that reduces tone of vascular smooth muscle. Experiments were designed to determine whether or not use of nicotine nasal spray for smoking cessation affects plasma levels of nitric oxide. Forty smokers self-administered nicotine by nasal spray (one 0.5 mg spray to each nostril). Blood samples were taken before the use of the nasal spray and at treatment day 7 for the measurement of cotinine by high pressure liquid chromatography and nitric oxide (NOx) by chemiluminescence. Age-comparable controls were never-smokers nonnicotine users recruited from laboratory personnel. Mean plasma concentrations of NOx from smokers before treatment were significantly greater compared with nonsmokers (23 +/- 10, n = 40 and 15 +/- 6, n = 13 nmoles/mL [mean +/- SD], respectively, P < 0.01). Plasma NOx in smokers was not significantly correlated with the average daily number of cigarettes smoked (r2 = 0.02, P > 0.05) but was positively and linearly correlated with plasma cotinine (r2 = 0.13, P < 0.02). In 32 self-reported abstinent smokers (confirmed by expired carbon monoxide < 9 ppm) using nicotine nasal spray, cotinine decreased by 64% from pretreatment levels of 284 +/- 103 to posttreatment levels of 90 +/- 58 ng/mL. Plasma NOx was unchanged and went from 23.0 +/- 10.1 at pretreatment to 21 +/- 12 nmoles/mL with nicotine treatment. These results suggest that nicotine-use, independent of cigarette smoking, affects plasma NOx.