The aim of this study was to evaluate the role of endothelium in mediating the response to acetylcholine in the thoracic aorta and coronary vessels of rats exposed to cigarette smoking. Total serum cholesterol was measured at the beginning and end of the experiment. 2. The relaxation response to acetylcholine was significantly impaired in the aortae of rats exposed to cigarette smoking (P < 0.05); and the coronary flow during the administration of acetylcholine (0.02 microgram/min.) was significantly reduced (P < 0.05). The total cholesterol plasma levels increased 31.13% in those exposed to smoke when compared to the controls (P < 0.05). 3. It is concluded that exposure to cigarette smoking increases total serum cholesterol levels, and also produces primary endothelial dysfunction in aorta rings and coronary vessels.
