A Study on the Excitation-Contraction Coupling of Myocardium ---Analysis on Isolated, perfused Hearts using Multi-Nuclear NMR Methods.

心肌兴奋-收缩耦合的研究——使用多核核磁共振方法分析离体灌注心脏。

• 批准号: 02045021
• 负责人: INOUE Michitoshi
• 金额: $ 2.82万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02045021/
• 关键词: Isolated perfused heart; Ischemia; Reperfusion injury; Intracellular calcium; Nuclear magnetic resonance; Sodium calcium exchange; Calcium channel; Glycolysis; 心筋; フッ素核磁気共鳴法

This research program focused on the mechanism for the disruption of intracellular calcium homeostasis induced by ischemia and reperfusion. Intracellular ionic calcium concentration ([Ca^<2+>]_i) was measured with fluorine-19 NMR (F-NMR) coupled with a calcium indicator, 5F-BAPTA. The results obtained in this program are as follows.1)[Ca^<2+>]_i significantly increased at the end of ischemia and during the early phase of reperfusion when hearts were subjected into 30-min ischemia at30ﾟC. The increase of [Ca^<2+>]_i was attenuated by pretreatment ofCa^<2+> channel blocker, indicating that opening of Ca^<2+> channel is one of the mechanism of Ca^<2+> increase during ischemia. 2)Hearts reperfused after 15-min global ischemia at 37ﾟshowed myocardial stunning. In contrast, hearts reperfused with high-[Na]_o. solution showed significantly better recovery. Nevertheless, reperfusion with solutions in which the additional Na was substituted either by sucrose or by choline chloride did not impro … More ve functional recovery, indicating that the beneficial effects of high-[Na]_o. reperfusion are not due either to high ionic strength or to high osmolarity. These results indicate that high-[Na]_o. reperfusion protects against stunning, supporting the idea that the Na^+/Ca^+ exchange plays an important role in the mechanism of stunned myocardium. 3)Myocardial content of sugar phosphates ([SP]) and [Ca^<2+>]_i were measured to elucidate the contribution of glycolysis to intracellular Ca^<2+> homeostasis. After the depletion of glycogen, the perfusion without substrate of glycolysis showed no significant changes in end-diastolic LV pressure (EDP) and [SP]. Even after the blockage of glycolysis, omission of glucose from the perfusate increased neither [SP] nor EDP. Nevertheless, addition of glucose to perfusate consistently increased EDP with accumulation of SP. F-NMR revealed that EDP correlates significantly with [Ca^<2+>]_i. These results indicate that disruption of intracellular Ca^<2+> homeostasis is caused by the accumulation of SP, rather than the inhibition of glycolysis. Less

该研究项目的重点是缺血和再灌注引起的细胞内钙稳态破坏的机制。用氟-19 NMR(F-NMR)结合钙指示剂5F-BAPTA测量细胞内离子钙浓度([Ca 2+ ]_i)。本程序获得的结果如下：1)当心脏在30℃下缺血30分钟时，[Ca^<2+>]_i在缺血末期和再灌注早期显着增加。 Ca^2+通道阻滞剂预处理可减弱[Ca^2+]_i的增加，表明Ca^2+通道的开放是缺血时Ca^2+增加的机制之一。 2) 37℃ 15 分钟整体缺血后，心脏再灌注显示心肌顿抑。相反，心脏用高[Na]_o再灌注。溶液显示出明显更好的恢复。然而，用蔗糖或氯化胆碱替代额外的Na的溶液进行再灌注并不能改善功能恢复，这表明高[Na]_o的有益作用。再灌注不是由于高离子强度或高渗透压造成的。这些结果表明高-[Na]_o。再灌注可防止心肌顿抑，支持 Na^+/Ca^+ 交换在心肌顿抑机制中发挥重要作用的观点。 3)测量心肌中磷酸糖([SP])和[Ca^2+]_i的含量以阐明糖酵解对细胞内Ca^2+稳态的贡献。糖原耗尽后，无糖酵解底物的灌注显示左心室舒张末压（EDP）和[SP]没有显着变化。即使在糖酵解被阻断后，灌注液中葡萄糖的缺失也不会增加 [SP] 和 EDP。然而，向灌注液中添加葡萄糖持续增加 EDP 并伴随 SP 积累。 F-NMR显示EDP与[Ca^2+]_i显着相关。这些结果表明细胞内Ca 2+ 稳态的破坏是由SP的积累引起的，而不是糖酵解的抑制。较少的

项目成果

Marban E: "Myocardial stunning and hibernation" Circulation. 83. 681-688 (1991)

Marban E：“心肌顿抑和冬眠”循环。

KUSUOKA H: "Pathophysiology and pathogenesis of contratile failure in stunned myocardium" Japanese Circulation Journal. 55. 878-884 (1991)

KUSUOKA H：“心肌顿抑中对抗性衰竭的病理生理学和发病机制”日本循环杂志。

KUSUOKA H: "Role of Sodium/Calcium exchange in the mechanism of myocardial stunning" Journal of American College of Cardiology. 21. 240-248 (1993)

KUSUOKA H：“钠/钙交换在心肌顿抑机制中的作用”美国心脏病学会杂志。

Yukihiro Koretsune: "Mechanisum of ischemic contractile failure:inexcitability,metabolite accumulation,or vascular collapse?" Circulation Research. 68. 255-262 (1991)

Yukihiro Koretsune：“缺血性收缩衰竭的机制：兴奋性、代谢物积累，还是血管崩溃？”

KUSUOKA H: "Myocardial energetics during ventriculal fibrillation investigated by magnetization transfer NMR spectroscopy" Circulation Research. 71. 1111-1122 (1992)

KUSUOKA H：“通过磁化转移核磁共振波谱研究心室颤动期间的心肌能量”循环研究。