Nicotine Impairs Smooth Muscle cAMP Signaling and Vascular Reactivity.

OBJECTIVE: This study aimed to determine nicotine's impact on receptor-mediated cyclic adenosine monophosphate (cAMP) synthesis in vascular smooth muscle (VSM). We hypothesize that nicotine impairs β adrenergic-mediated cAMP signaling in VSM, leading to altered vascular reactivity. METHODS: The effects of nicotine on cAMP signaling and vascular function were systematically tested in aortic VSM cells and acutely isolated aortas from mice expressing the cAMP sensor (T)Epac(VV) (Camper), specifically in VSM (e.g., Camper(SM)). RESULTS: Isoproterenol (ISO)-induced β-adrenergic production of cAMP in VSM was significantly reduced in cells from second-hand smoke (SHS)-exposed mice and cultured wild-type VSM treated with nicotine. The decrease in cAMP synthesis caused by nicotine was verified in freshly isolated arteries from a mouse that had cAMP sensor expression in VSM (e.g., Camper(SM) mouse). Functionally, the changes in cAMP signaling in response to nicotine hindered ISO-induced vasodilation, but this was reversed by immediate PDE3 inhibition. CONCLUSIONS: These results imply that nicotine alters VSM β adrenergic-mediated cAMP signaling and vasodilation, which may contribute to the dysregulation of vascular reactivity and the development of vascular complications for nicotine-containing product users.