Chronic exposure to nicotine alters endothelium-dependent arteriolar dilatation: effect of superoxide dismutase

Department of Physiology and Biophysics, University of Nebraska Medical Center, Omaha, Nebraska 68198-4575 The first goal of this study was to determine whether chronic injection of nicotine alters endothelium-dependent arteriolar dilatation. We measured the diameter of cheek pouch resistance arterioles (~50 µm in diameter) in response to endothelium-dependent (acetylcholine and ADP) and -independent (nitroglycerin) agonists in control hamsters and hamsters treated with nicotine (2 µg · kg 1 · day 1 for 2-3 wk). In control hamsters, acetylcholine (0.1 and 1.0 µM) dilated arterioles by 13 ± 2 and 31 ± 3%, respectively, and ADP (1.0 and 10 µM) dilated arterioles by 18 ± 1 and 30 ± 1%, respectively. In contrast, acetylcholine (0.1 and 1.0 µM) dilated arterioles by only 5 ± 2 and 12 ± 3%, respectively, and ADP (1.0 and 10 µM) dilated arterioles by only 7 ± 2 and 13 ± 3%, respectively, in animals treated with nicotine ( P