Aim This study sought to investigate the effect of chronic nicotine exposure on vascular function and to identify the underlying mechanisms.Methods Isolated organ bath studies were performed to examine the effects of chronic nicotine exposure on vascular reactivity of the aorta in SpragueDawley rats.We used various analogues and blockers of the cGMPdependent protein kinase (PKG) pathway as well as molecular techniques to identify the underlying mechanisms.Results Chronic nicotine exposure reduced periaortic fat and specifically enhanced smooth muscle relaxation, although aortic adventitial fat and endothelium function were not affected.The soluble guanylyl cyclase inhibitor ODQ or PKG inhibitor Rp8BrPETcGMP abolished the difference in relaxation between the saline and nicotine group, and the cGMP analogue 8BrcGMP mimicked the difference in relaxation.PKG protein expression and activity were not altered after nicotine treatment.Conclusion Chronic nicotine exposure enhances vascular smooth muscle relaxation through a cGMPdependent PKG pathway.Our findings provide novel insights into nicotine pharmacology.