Effect of cigarette smoke extract on arteriolar dilatation in vivo.

The goal of this study was to determine whether cigarette smoke extract alters dilatation of arterioles in vivo in response to agonists that produce activation of ATP-sensitive potassium channels and activation of adenylate cyclase. By using intravital microscopy, we measured diameter of arterioles contained within the microcirculation of the hamster cheek pouch during suffusion with agonists in the absence and presence of cigarette smoke extract (0.1, 0.5, and 1.0%). Before treatment with cigarette smoke extract, activation of ATP-sensitive potassium channels with aprikalim and cromakalim produced dose-related dilatation of cheek pouch arterioles. Similarly, activation of adenylate cyclase with isoproterenol and forskolin produced dose-related dilatation of cheek pouch arterioles before treatment with cigarette smoke extract. Superfusion of 0.1% cigarette smoke extract did not change baseline diameter of arterioles and did not alter responses of cheek pouch arterioles to activation of ATP-sensitive potassium channels and adenylate cyclase. Superfusion of 0.5 and 1.0% cigarette smoke extract also did not alter baseline diameter of arterioles but did impair dilatation of arterioles in response to activation of ATP-sensitive potassium channels and adenylate cyclase. These findings suggest that cigarette smoke extract impairs dilatation of resistance arterioles in response to activation of important cellular dilator pathways.