VASCULAR CYTOCHROME P450 RELATED ARACHIDONIC ACID PRODUCTS

这是一项研究细胞色素P450(P450)来源的建议 二十碳二烯类化合物是花生四烯酸(AA)血管扩张的中介物 作为血管收缩反应的调节剂，并确定其 有助于调节肾功能和血压。在 一种内皮依赖性血管扩张剂--大鼠离体灌流肾 AA的作用可以在收缩形成时被揭示出来 吲哚美辛阻断内皮细胞内过氧化物质，使灌流压升高 使用苯肾上腺素。这种血管扩张作用可被血管紧张素转换酶抑制剂减弱。 P450，并相应地增加和降低诱导和 P45O耗竭。同样，缓激肽的肾血管扩张作用 (BK)表现出一种一氧化氮不依赖的成分，该成分被还原 P450的抑制剂。此外，AA和AA的肾血管扩张作用 K+通道的阻断剂可降低BK。作为环氧化物，除了14， 15EET是大鼠肾脏中的血管扩张剂，已有报道称 激活血管平滑肌上的K+通道，我们假设AA是 通过P450转化为介导肾血管扩张剂的环氧化物 AA通过激活K+通道发挥作用。因此，第一个目标是 确定环氧化物是否能起到超极化作用 因素。因此，我们将关联AA的肾血管扩张活性。 用气相色谱-质谱法测定环氧化物的释放，以及 环氧合酶抑制剂以及解决肾血管的影响 EETs的区域和立体异构体以及K+通道的作用。第二 AIM将测试环氧化物的假设，环氧化物是对 血管活性激素，中等程度的血管收缩刺激作用 荷尔蒙。因此，17-ODYA增强了肾血管对苯肾上腺素的反应。 我们将测定环氧化物对血管紧张素II、精氨酸加压素的释放 和苯肾上腺素，并测试环氧化物和环氧合酶的作用 这些激素对肾脏血管收缩反应的抑制作用。第三 目的：确定环氧化物在肾脏血管反应改变中的作用。 对高血压患者进行AA治疗，是基于对肾脏血管扩张剂的观察 与WKY大鼠相比，SHR大鼠对AA和BK的反应显著增强。 因此，我们将确定环氧化物的释放对AA，肾脏的反应 对环氧化物的反应性和环氧合酶的体内效应 对肾功能、血压和升压反应的抑制作用 高血压大鼠和正常血压大鼠。这些研究将描述一种 新的血管扩张系统及其表达和功能的测定 在血压正常和高血压中的意义。

This is a proposal to investigate cytochrome P450 (P450) -derived eicosanoids as mediators of arachidonic acid (AA) -induced vasodilation and as modulators of vasoconstrictor responses and to determine their contribute to the regulation of renal function and blood pressure. In the isolated perfused kidney of the rat, an endothelium-dependent vasodilator effect of AA can be uncovered when the formation of constrictor endoperioxides is blocked by indomethacin and perfusion pressure elevated with phenylephrine. This vasodilator effect is attenuated by inhibitors of P450 and correspondingly increased and decreased by induction and depletion of P45O. Similarly, the renal vasodilator effect of bradykinin (BK) exhibits a nitric oxide-independent component that is reduced by inhibitors of P450. Moreover, the renal vasodilator effects of both AA and BK are reduced by inhibitors of K+ channels. As epoxides, except 14, 15EET, are vasodilator in the rat kidney and have been reported to activate K+ channels in vascular smooth muscle, we hypothesize that AA is converted, via P450, to an epoxide that mediates the renal vasodilator effect of AA by activating K+ channels. Thus, the first aim is to determine whether an epoxide can assume the role of an hyperpolarizing factor. Therefore, we shall correlate the renal vasodilator activity of AA to the release of epoxides, measured by GC-MS, and the effects of epoxygenase inhibitors as well as addressing the renal vascular effects of regio- and stereoisomers of EETs and the role of K+ channels. The second aim will test the hypothesis that epoxides, released in response to vasoactive hormones, moderate vasoconstrictor effects of the stimulating hormone. Thus, 17-ODYA enhances renal vascular responses-to phenylephrine. We shall determine epoxide release to angiotensin II, arginine vasopressin and phenylephrine and test the effects of epoxides and epoxygenase inhibitors on renal vasoconstrictor responses to these hormones. The third aim, to determine the role of epoxides in altered renal vascular responses to AA in hypertension, is based on observations that renal vasodilator responses to AA and BK are greatly enhanced in SHR versus WKY rats. Consequently, we will determine epoxide release in response to AA, renal responsiveness to epoxides and the in vivo effects of epoxygenase inhibition on renal function, blood pressure-and pressor responsiveness in hypertensive and normotensive rats. These studies will characterize a novel vasodilator system and determine its expression and functional significance in normotension and hypertension.