Cuong Dang Van, Kim Nari, Youm Jae Boum, Joo Hyun, Warda Mohamad, Lee Jae-Wha, Park Won Sun, Kim Taeho, Kang Sunghyun, Kim Hyungkyu, Han Jin
Mitochondrial Signaling Laboratory, Department of Physiology and Biophysics, College of Medicine, Cardiovascular and Metabolic Disease Center, Biohealth Products Research Center, Inje University, Busan, Korea.
Am J Physiol Heart Circ Physiol. 2006 May;290(5):H1808-17. doi: 10.1152/ajpheart.00772.2005. Epub 2005 Dec 9.
Nitric oxide (NO) plays an important role in anoxic preconditioning to protect the heart against ischemia-reperfusion injuries. The present work was performed to study better the NO-cGMP-protein kinase G (PKG) signaling pathway in the activation of both sarcolemmal and mitochondrial ATP-sensitive K+ (KATP) channels during anoxic preconditioning (APC) and final influence on reducing anoxia-reperfusion (A/R)-induced cardiac damage in rat hearts. The upstream regulating elements controlling NO-cGMP-PKG signal-induced KATP channel opening that leads to cardioprotection were investigated. The involvement of both inducible and endothelial NO synthases (iNOS and eNOS) in the progression of this signaling pathway was followed. Final cellular outcomes of ischemia-induced injury after different preconditioning in the form of lactate dehydrogenase release, DNA strand breaks, and malondialdehyde formation as indexes of cell injury and lipid peroxidation, respectively, were investigated. The lactate dehydrogenase and malondialdehyde values decreased in the groups that underwent preconditioning periods with specific mitochondrial KATP channels opener diazoxide (100 microM), nonspecific mitochondrial KATP channels opener pinacidil (50 microM), S-nitroso-N-acetylpenicillamine (SNAP, 300 microM), or beta-phenyl-1,N2-etheno-8-bromoguanosine-3',5'-cyclicmonophosphorothioate, Sp-isomer (10 microM) before the A/R period. Preconditioning with SNAP significantly reduced the DNA damage. The effect was blocked by glibenclamide (50 microM), 5-hydroxydecanoate (100 microM), NG-nitro-L-arginine methyl ester (200 microM), and beta-phenyl-1,N2-etheno-8-bromoguanosine-3',5'-cyclic monophosphorothioate, Rp-isomer (1 microM). The results suggest iNOS, rather than eNOS, as the major contributing NO synthase during APC treatment. Moreover, the PKG shows priority over NO as the upstream regulator of NO-cGMP-PKG signal-induced KATP channel opening that leads to cardioprotection during APC treatment.
一氧化氮（NO）在缺氧预处理中发挥重要作用，以保护心脏免受缺血再灌注损伤。开展本研究是为了更好地研究缺氧预处理（APC）过程中，NO - 环磷酸鸟苷 - 蛋白激酶G（PKG）信号通路在肌膜和线粒体ATP敏感性钾离子（KATP）通道激活中的作用，以及其对减轻大鼠心脏缺氧再灌注（A/R）诱导的心脏损伤的最终影响。研究了控制NO - cGMP - PKG信号诱导KATP通道开放从而实现心脏保护的上游调节元件。追踪了诱导型和内皮型一氧化氮合酶（iNOS和eNOS）在该信号通路进展中的参与情况。分别以乳酸脱氢酶释放、DNA链断裂和丙二醛形成作为细胞损伤和脂质过氧化指标，研究了不同预处理后缺血诱导损伤的最终细胞结局。在A/R期之前，用特异性线粒体KATP通道开放剂二氮嗪（100微摩尔）、非特异性线粒体KATP通道开放剂匹那地尔（50微摩尔）、S - 亚硝基 - N - 乙酰青霉胺（SNAP，300微摩尔）或β - 苯基 - 1，N2 - 乙烯基 - 8 - 溴鸟苷 - 3'，5' - 环磷硫酯，Sp - 异构体（10微摩尔）进行预处理的组中，乳酸脱氢酶和丙二醛值降低。用SNAP预处理可显著减少DNA损伤。该作用被格列本脲（50微摩尔）、5 - 羟基癸酸（100微摩尔）、NG - 硝基 - L - 精氨酸甲酯（200微摩尔）和β - 苯基 - 1，N2 - 乙烯基 - 8 - 溴鸟苷 - 3'，5' - 环磷硫酯，Rp - 异构体（1微摩尔）阻断。结果表明，在APC治疗期间，iNOS而非eNOS是产生NO的主要一氧化氮合酶。此外，在APC治疗期间，作为NO - cGMP - PKG信号诱导KATP通道开放从而实现心脏保护的上游调节因子，PKG比NO更具优先性。
