Recently, increasing evidence suggests that the antihypertensive drug nifedipine acts as a protective agent for endothelial cells, and that the activity is unrelated to its calcium channel blocking. Nifedipine is unstable under light and reportedly decomposes to a stable nitrosonifedipine (NO-NIF). NO-NIF has no antihypertensive effect, and it has been recognized as a contaminant of nifedipine. The present study for the first time demonstrated that NO-NIF changed to a NO-NIF radical in a time-dependent manner when it interacted with human umbilical vein endothelial cells (HUVECs). The electron paramagnetic resonance (EPR) signal of NO-NIF radicals in HUVECs showed an asymmetric pattern suggesting that the radicals were located in the membrane. The NO-NIF radicals had radical scavenging activity for 1,1-diphenyl-2-picrylhydrazyl, whereas neither NO-NIF nor nifedipine did. In addition, the NO-NIF radical more effectively quenched lipid peroxides than NO-NIF or nifedipine. Furthermore, NO-NIF attenuated the superoxide-derived free radicals in HUVECs stimulated with LY83583, and suppressed iron-nitrilotriacetic acid (Fe-NTA)-induced cytotoxicity in rat pheochromocytoma (PC12) cells. Our findings suggest that NO-NIF is a candidate for a new class of antioxidative drugs that protect cells against oxidative stress.
最近,越来越多的证据表明,抗高血压药物
硝苯地平可作为内皮细胞的保护剂,并且该活性与其
钙通道阻断无关。
硝苯地平在光下不稳定,据报道会分解为稳定的亚硝
硝苯地平 (NO-NIF)。 NO-NIF没有降压作用,已被认为是
硝苯地平的污染物。本研究首次证明NO-NIF与人脐静脉内皮细胞(HU
VEC)相互作用时,以时间依赖性方式转变为NO-NIF自由基。 HU
VEC 中 NO-NIF 自由基的电子顺磁共振 (EPR) 信号显示出不对称模式,表明自由基位于膜中。 NO-NIF自由基对1,1
-二苯基-2-三硝苯
肼具有自由基清除活性,而NO-NIF和
硝苯地平都没有。此外,NO-NIF 自由基比 NO-NIF 或
硝苯地平更有效地淬灭脂质过氧化物。此外,NO-NIF 减弱了 LY83583 刺激的 HU
VEC 中的超氧化物衍生自由基,并抑制了
次氮基三乙酸铁 (Fe-
NTA) 诱导的大鼠嗜
铬细胞瘤 (PC12) 细胞的细胞毒性。我们的研究结果表明,NO-NIF 是一类新型抗氧化药物的候选者,可以保护细胞免受氧化应激。