Transdermal nicotine mimics the smoking-induced endothelial dysfunction.
BACKGROUND
Cigarette smoking is a major risk factor for coronary artery disease and causes endothelial dysfunction, perhaps by decreasing the availability of nitric oxide availability in arteries and veins. Nicotine in cigarette smoke may be responsible for this impaired endothelial response.


METHODS
We studied nine healthy nonsmokers and 12 healthy mild to moderate smokers by use of the dorsal hand vein compliance technique. Dose-response curves to bradykinin and sodium nitroprusside were obtained to test the endothelium-dependent and endothelium-independent vasorelaxation before and during the use of a nicotine (21 mg) patch. Mean arterial blood pressure and heart rate were measured beat-to-beat during the 4-hour study and serial blood samples were drawn to assay plasma thromboxane B2 levels.


RESULTS
Transdermal nicotine reduced the venous responsiveness to bradykinin in nonsmokers (Emax = 88.0% +/- 17.9% and 54.3% +/- 14.9%, respectively, before and after the nicotine patch; P < .05); the latter response was similar to that in smokers (Emax = 56.3% +/- 16.6%). Sodium nitroprusside-induced venodilation was unaltered. Mean arterial blood pressure increased in both smokers and nonsmokers. Transdermal nicotine increased the plasma thromboxane B2 concentrations only among nonsmokers.


CONCLUSIONS
These findings indicate that nicotine can have a major role in the impaired endothelial function in smokers. The results probably also reflect what occurs in arterial beds because the nicotine patches increased the mean arterial blood pressure in both smokers and nonsmokers.
Sabha
M
M
Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, São Paulo, Brazil.
Tanus-Santos
J E
JE
Toledo
J C
JC
Cittadino
M
M
Rocha
J C
JC
Moreno
H
H
D000279:Administration, Cutaneous; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D001920:Bradykinin / Q000494:pharmacology; D018592:Cross-Over Studies; D004347:Drug Interactions; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology; D012907:Smoking / Q000097:blood / Q000473:pathology* / Q000503:physiopathology; D013929:Thromboxane B2 / Q000097:blood; D014664:Vasodilation / Q000187:drug effects
D018722:Nicotinic Agonists; D009599:Nitroprusside; D013929:Thromboxane B2; D009538:Nicotine; D001920:Bradykinin