Division of Experimental Cardiology, Department of Cardiology, Thoraxcenter, Cardiovascular Research School Erasmus University Rotterdam, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands.
Am J Physiol Heart Circ Physiol. 2012 Apr 15;302(8):H1747-55. doi: 10.1152/ajpheart.00648.2011. Epub 2012 Feb 3.
A significant endothelium-dependent vasodilation persists after inhibition of nitric oxide synthase (NOS) and cyclooxygenase (COX) in the coronary vasculature, which has been linked to the activation of cytochrome P-450 (CYP) epoxygenases expressed in endothelial cells and subsequent generation of vasodilator epoxyeicosatrienoic acids. Here, we investigated the contribution of CYP 2C9 metabolites to regulation of porcine coronary vasomotor tone in vivo and in vitro. Twenty-six swine were chronically instrumented. Inhibition of CYP 2C9 with sulfaphenazole (5 mg/kg iv) alone had no effect on bradykinin-induced endothelium-dependent coronary vasodilation in vivo but slightly attenuated bradykinin-induced vasodilation in the presence of combined NOS/COX blockade with N(ω)-nitro-L-arginine (20 mg/kg iv) and indomethacin (10 mg/kg iv). Sulfaphenazole had minimal effects on coronary resistance vessel tone at rest or during exercise. Surprisingly, in the presence of combined NOS/COX blockade, a significant coronary vasodilator response to sulfaphenzole became apparent, both at rest and during exercise. Subsequently, we investigated in isolated porcine coronary small arteries (∼250 μm) the possible involvement of reactive oxygen species (ROS) in the paradoxical vasoconstrictor influence of CYP 2C9 activity. The vasodilation by bradykinin in vitro in the presence of NOS/COX blockade was markedly potentiated by sulfaphenazole under control conditions but not in the presence of the ROS scavenger N-(2-mercaptoproprionyl)-glycine. In conclusion, CYP 2C9 can produce both vasoconstrictor and vasodilator metabolites. Production of these metabolites is enhanced by combined NOS/COX blockade and is critically dependent on the experimental conditions. Thus production of vasoconstrictors slightly outweighed the production of vasodilators at rest and during exercise. Pharmacological stimulation with bradykinin resulted in vasodilator CYP 2C9 metabolite production when administered in vivo, whereas vasoconstrictor CYP 2C9 metabolites, most likely ROS, were dominant when administered in vitro.
在冠状动脉血管中抑制一氧化氮合酶 (NOS) 和环氧化酶 (COX) 后，仍然存在显著的内皮依赖性血管扩张，这与内皮细胞中表达的细胞色素 P-450 (CYP) 环氧化物水解酶的激活有关，随后产生血管扩张性环氧二十碳三烯酸。在这里，我们研究了 CYP 2C9 代谢物对体内和体外猪冠状动脉血管舒缩张力的调节作用。26 头猪被慢性植入仪器。单独使用磺胺苯唑 (5mg/kg iv) 抑制 CYP 2C9 对体内缓激肽诱导的内皮依赖性冠状动脉血管舒张没有影响，但在联合 NOS/COX 阻断剂 N(ω)-硝基-L-精氨酸 (20mg/kg iv) 和吲哚美辛 (10mg/kg iv) 存在时，轻微减弱了缓激肽诱导的血管舒张。磺胺苯唑对休息或运动时冠状动脉阻力血管张力的影响很小。令人惊讶的是，在联合 NOS/COX 阻断的情况下，磺胺苯唑明显出现了一种显著的冠状动脉血管舒张反应，无论是在休息时还是在运动时。随后，我们在分离的猪冠状动脉小动脉（约 250μm）中研究了活性氧 (ROS) 可能参与 CYP 2C9 活性的这种矛盾性血管收缩作用。在 NOS/COX 阻断的情况下，体外缓激肽的血管舒张在对照条件下明显被磺胺苯唑增强，但在 ROS 清除剂 N-(2-巯基丙酰基)-甘氨酸存在下则没有。总之，CYP 2C9 可以产生血管收缩和血管舒张代谢物。这些代谢物的产生在联合 NOS/COX 阻断的情况下增强，并且严重依赖于实验条件。因此，在休息和运动时，血管收缩代谢物的产生略高于血管舒张代谢物的产生。体内给予缓激肽进行药理学刺激会导致血管舒张性 CYP 2C9 代谢产物的产生，而体外给予则会导致血管收缩性 CYP 2C9 代谢产物，很可能是 ROS，占主导地位。
