Background: Smoking is a major risk factor for cardiovascular disease. The present study was undertaken to examine if cigarette smoking translates into reduced relaxant responses of the peripheral microcirculation.
Methods: The cutaneous forearm blood flow was measured by laser Doppler flowmetry. The vasodilator response to the iontophorectic administration of acetylcholine (ACh), acting via an endothelial mechanism, and sodium nitroprusside (SNP), and acting via a smooth muscle mechanism were studied. The study population consisted of 17 nonsmokers and 17 current smokers (mean age 64+/-2 years, 13 females and 4 males) in each matched group.
Results: There was no difference between the groups in baseline characteristics or in basal flow. Smokers showed however significantly reduced responses to both ACh (mean +/- SEM, from 973+/-137% in nonsmokers to 651+/-114% in smokers, p<0.05) and SNP (from 575+/-111% in nonsmokers to 355+/-83% in smokers, p<0.05). The response to the local heating (44 degrees C) was reduced in smokers (from 1188+/-215% in nonsmokers to 714+/-107% in smokers, p<0.01). In addition, there was no difference between men and women within the groups.
Conclusions: The data show that cigarette smoking results in reduced peripheral microvascular responses to both endothelial and smooth muscle cell stimulation in healthy subjects, suggesting a generalized microvascular vasomotor function.
Keywords: acetylcholine; cutaneous microcirculation; nonsmokers; smoking; vasomotor function.