Division of Cardiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
Clin Exp Pharmacol Physiol. 2021 Jul;48(7):996-1006. doi: 10.1111/1440-1681.13502. Epub 2021 Apr 20.
Thromboxane A (TXA ) participates in many pathophysiological processes of coronary artery disease. However, its mechanism of TXA -induced contraction in the coronary artery remains to be clarified. A multi myograph system was used to measure the isometric tension of the mouse coronary arteries and identify the effect and pathway of TXA analogues U46619. Confocal laser scanning microscopy was used to measure the intracellular calcium concentration ([Ca ] ) in mouse coronary artery smooth muscle cells. Results from the experiment had shown that contraction in coronary artery was generated by U46619 in a concentration-dependent manner, which was completely abolished by a specific TXA receptor blocker, GR32191. PI-PLC inhibitors U73122 and D609 and Rho-Kinase inhibitor Y-27632 can block the U46619 elicited coronary artery contraction in a dose-dependent manner. Then, the vasoconstriction response to U46619 was obviously inhibited by two pan-PKC inhibitors chelerythrine or Gӧ6983, and a selective PKCδ inhibitor rottlerin, but was not blocked by a selective PKCζ inhibitor PKC-PS or a selective PKCβ inhibitor hispidin. Meanwhile, the PKC activator PDBu-induced vasoconstriction was significantly inhibited by 1 μmol/L nifedipine, then mostly inhibited by 100 μmol/L 2-APB and 10 μmol/L Y27632. We further found that the response to U46619 was inhibited, respectively, by three calcium channel blockers nifedipine, SKF96356 or 2-APB in a concentration-dependent manner. Although Store-operated Ca (SOC) channels generated the increase of [Ca ] in mouse coronary artery smooth muscle cells, SOC channels did not contribute to the vasoconstriction in mouse coronary arteries. Caffeine-induced sarcoplasmic reticulum (SR) Ca release could obviously induce coronal vasoconstriction. In addition, NPPB, a cell membrane Ca activated C1 channel blocker, could obviously inhibit the U46619-induced vasoconstriction. The U46619-induced mouse coronary artery contraction was involved in the increase in [Ca ] mediated by Cav1.2, TRPC channels and SR release through the activation of G-protein-coupled TP receptors and the kinases signalling pathway in TP downstream proteins, while SOC channels did not participate in the vasoconstriction.
血栓素 A（TXA）参与冠状动脉疾病的许多病理生理过程。然而，其在冠状动脉中诱导收缩的机制仍有待阐明。使用多肌描记系统测量小鼠冠状动脉的等长张力，并鉴定 TXA 类似物 U46619 的作用和途径。共聚焦激光扫描显微镜用于测量小鼠冠状动脉平滑肌细胞中的细胞内钙浓度([Ca])。实验结果表明，U46619 以浓度依赖性方式产生冠状动脉收缩，该收缩被特定的 TXA 受体阻滞剂 GR32191 完全阻断。PI-PLC 抑制剂 U73122 和 D609 和 Rho-激酶抑制剂 Y-27632 可剂量依赖性地阻断 U46619 引起的冠状动脉收缩。然后，两种泛 PKC 抑制剂 Chelerythrine 或 Gӧ6983 和选择性 PKCδ抑制剂 Rottlerin 明显抑制 U46619 引起的血管收缩反应，但不被选择性 PKCζ抑制剂 PKC-PS 或选择性 PKCβ抑制剂 Hispidin 阻断。同时，PKC 激活剂 PDBu 诱导的血管收缩明显被 1μmol/L 硝苯地平抑制，然后被 100μmol/L 2-APB 和 10μmol/L Y27632 大部分抑制。我们进一步发现，U46619 的反应分别被硝苯地平、SKF96356 或 2-APB 三种钙通道阻滞剂浓度依赖性抑制。尽管 Store-operated Ca（SOC）通道引起小鼠冠状动脉平滑肌细胞[Ca]的增加，但 SOC 通道不参与小鼠冠状动脉的血管收缩。咖啡因诱导的肌浆网（SR）Ca 释放可明显引起冠状血管收缩。此外，细胞膜 Ca 激活 C1 通道阻滞剂 NPPB 可明显抑制 U46619 诱导的血管收缩。U46619 诱导的小鼠冠状动脉收缩涉及 Cav1.2、TRPC 通道和 SR 释放引起的[Ca]增加，通过 G 蛋白偶联 TP 受体的激活和 TP 下游蛋白激酶信号通路，而 SOC 通道不参与血管收缩。
