Cigarette smoke extract attenuates endothelium-dependent arteriolar dilatation in vivo

The purpose of this study was to examine the effects of cigarette smoke extract on endothelium-dependent and endothelium-independent dilatation of arterioles in vivo. Using intravital microscopy, we measured diameter of arterioles contained within the microcirculation of the hamster cheek pouch during suffusion with acetylcholine and nitroglycerin, before and after treatment with cigarette smoke extract. Under control conditions, acetylcholine and nitroglycerin produced dose-related dilatation of cheek pouch arterioles. Superfusion of cigarette smoke extract (1.0%) did not alter baseline diameter of arterioles or vasodilatation in response to nitroglycerin but impaired dilatation of arterioles in response to acetylcholine. Next, we examined the possibility that impaired dilatation of cheek pouch arterioles in response to acetylcholine after exposure to cigarette smoke extract may be related to the release of substances produced via the cyclooxygenase pathway. In indomethacin-pretreated hamsters, acetylcholine produced similar vasodilatation before and after exposure to cigarette smoke extract. Thus these findings suggest that cigarette smoke extract impairs endothelium-dependent responses of cheek pouch arterioles. The mechanism of impaired responses of cheek pouch arterioles after exposure to cigarette smoke extract appears to be related to the release of substances produced via the cyclooxygenase pathway.