Lang D, Smith J A, Lewis M J
Department of Pharmacology & Therapeutics, University of Wales College of Medicine, Heath Park, Cardiff.
Br J Pharmacol. 1993 Feb;108(2):290-2. doi: 10.1111/j.1476-5381.1993.tb12796.x.
Endothelium-dependent and -independent relaxation of aortic ring preparations was assessed and nitric oxide (NO) synthase activity measured in the lung, and cerebellum of cholesterol-fed and normal rabbits. Endothelium-dependent relaxation of acetylcholine and ATP was depressed while that to the calcium ionophore, A23187, was unaltered in the cholesterol-fed group. Relaxation to sodium nitroprusside was however greater in aortae from the cholesterol-fed animals. Neither Ca(2+)-dependent nor Ca(2+)-independent NO synthase activity could be detected in aortae or hearts taken from either group of animals. Activity of both enzymes was unaltered in cerebellae from both groups of animals. Activity of the Ca(2+)-independent enzyme was however significantly greater (ca. 2 fold) in lungs from the cholesterol-fed rabbits though the activity of the Ca(2+)-dependent NO synthase was not significantly altered. This finding may account for the increased production of nitrogen oxides previously observed in this model of hypercholesterolaemia.
评估了胆固醇喂养兔和正常兔的主动脉环标本的内皮依赖性和非内皮依赖性舒张情况，并测定了肺和小脑的一氧化氮（NO）合酶活性。在胆固醇喂养组中，乙酰胆碱和ATP的内皮依赖性舒张受到抑制，而对钙离子载体A23187的舒张未改变。然而，胆固醇喂养动物的主动脉对硝普钠的舒张反应更大。在两组动物的主动脉或心脏中均未检测到钙依赖性或钙非依赖性NO合酶活性。两组动物小脑的两种酶活性均未改变。然而，胆固醇喂养兔肺中钙非依赖性酶的活性显著更高（约2倍），而钙依赖性NO合酶的活性未显著改变。这一发现可能解释了先前在该高胆固醇血症模型中观察到的氮氧化物产生增加的现象。
