Myocardial ischemia/reperfusion injury worsens in the absence of nitric oxide synthase (NOS). Cilnidipine, a Ca²⁺ channel blocker, has been reported to activate endothelial NOS (eNOS) and increases nitric oxide (NO) in vascular endothelial cells. We examined whether pretreatment with cilnidipine could attenuate cardiac cell deaths including apoptosis caused by hypoxia/reoxygenation (H/R) injury. HL-1 mouse atrial myocytes as well as H9c2 rat ventricular cells were exposed to H/R, and cell viability was evaluated by an autoanalyzer and flow cytometry; eNOS expression, NO production, and electrophysiological properties were also evaluated by western blotting, colorimetry, and patch clamping, respectively, in the absence and presence of cilnidipine. Cilnidipine enhanced phosphorylation of eNOS and NO production in a concentration-dependent manner, which was abolished by siRNAs against eNOS or an Hsp90 inhibitor, geldanamycin. Pretreatment with cilnidipine attenuated cell deaths including apoptosis during H/R; this effect was reproduced by an NO donor and a xanthine oxidase inhibitor. The NOS inhibitor L-NAME abolished the protective action of cilnidipine. Pretreatment with cilnidipine also attenuated H9c2 cell death during H/R. Additional cilnidipine treatment during H/R did not significantly enhance its protective action. There was no significant difference in the protective effect of cilnidipine under normal and high Ca²⁺ conditions. Action potential duration (APD) of HL-1 cells was shortened by cilnidipine, with this shortening augmented after H/R. L-NAME attenuated the APD shortening caused by cilnidipine. These findings indicate that cilnidipine enhances NO production, shortens APD in part by L-type Ca²⁺ channel block, and thereby prevents HL-1 cell deaths during H/R.

在没有一氧化氮合酶 (NOS) 的情况下，心肌缺血/再灌注损伤会恶化。西尼地平，一种 Ca ²⁺据报道，通道阻滞剂可激活内皮 NOS (eNOS) 并增加血管内皮细胞中的一氧化氮 (NO)。我们检查了西尼地平预处理是否可以减轻心脏细胞死亡，包括由缺氧/复氧 (H/R) 损伤引起的细胞凋亡。将HL-1小鼠心房肌细胞和H9c2大鼠心室细胞暴露于H/R，并通过自动分析仪和流式细胞仪评估细胞活力；在西尼地平不存在和存在的情况下，还通过蛋白质印迹、比色法和膜片钳分别评估了 eNOS 表达、NO 产生和电生理特性。Cilnidipine 以浓度依赖性方式增强 eNOS 的磷酸化和 NO 的产生，而针对 eNOS 或 Hsp90 抑制剂格尔德霉素的 siRNA 消除了这种磷酸化。西尼地平预处理可减轻细胞死亡，包括 H/R 期间的细胞凋亡；这种效应是由一氧化氮供体和黄嘌呤氧化酶抑制剂复制的。NOS 抑制剂 L-NAME 消除了西尼地平的保护作用。西尼地平预处理也减弱了 H/R 期间的 H9c2 细胞死亡。在 H/R 期间额外的西尼地平治疗并没有显着增强其保护作用。西尼地平在正常和高Ca情况下的保护作用无显着差异 在 H/R 期间额外的西尼地平治疗并没有显着增强其保护作用。西尼地平在正常和高Ca情况下的保护作用无显着差异 在 H/R 期间额外的西尼地平治疗并没有显着增强其保护作用。西尼地平在正常和高Ca情况下的保护作用无显着差异²⁺条件。西尼地平缩短了 HL-1 细胞的动作电位持续时间 (APD)，这种缩短在 H/R 后增强。L-NAME 减弱了由西尼地平引起的 APD 缩短。这些发现表明，西尼地平通过 L 型 Ca ²⁺通道阻滞部分提高 NO 的产生，缩短 APD，从而防止 H/R 期间的 HL-1 细胞死亡。