凝血酶通过释放肌醇1,4,5-三磷酸在心肌再灌注期间的致心律失常作用。

Arrhythmogenic action of thrombin during myocardial reperfusion via release of inositol 1,4,5-triphosphate.

作者信息

Jacobsen A N, Du X J, Lambert K A, Dart A M, Woodcock E A

机构信息

Cellular Biochemistry Laboratory, Baker Medical Research Institute, Melbourne, Australia.

出版信息

Circulation. 1996 Jan 1;93(1):23-6. doi: 10.1161/01.cir.93.1.23.

DOI:10.1161/01.cir.93.1.23

PMID:8616935

Abstract

BACKGROUND

Cardiac reperfusion initiates release of inositol 1,4,5-triphosphate [Ins(1,4,5)P3] and arrhythmogenesis via norepinephrine stimulation of alpha1-adrenergic receptors. The present study examines arrhythmogenic effects of thrombin-stimulated Ins(1,4,5)P3 release under these conditions.

METHODS AND RESULTS

[3H]Ins(1,4,5)P3 release was measured in [3H]inositol-labeled rat hearts by high-performance liquid chromatography. Arrhythmia studies were performed in buffer-perfused rat hearts. Two-minute reperfusion after 20 minutes of global ischemia increased [3H]Ins(1,4,5)P3 from 1123 +/- 77 to 2238 +/- 44 cpm/mg tissue. No increase was observed in catecholamine-depleted hearts (755 +/- 89 cpm/mg). The addition of thrombin (5 IU/mL) or thrombin receptor agonist peptide (TRAP(1-6), 50 micromol/L) restored the reperfusion Ins(1,4,5)P3 response (thrombin, 1518 +/- 68 cpm/mg and TRAP(1-6), 1755 +/- 128 cpm/mg). Ins(1,4,5)P3 release initiated by norepinephrine or thrombin was inhibited by gentamicin (150 micromol/L; 986 +/- 52 and 868 +/- 125 cpm/mg, respectively). The thrombin response was inhibited by the phospholipase C inhibitor U-73122 (5 micromol/L; 394 +/- 59 cpm/mg) but not by its inactive isomer U-73343. The norepinephrine response was not inhibited by U-73122 (2126 +/- 74 cpm/mg). Ventricular tachycardia and ventricular fibrillation were observed in intact hearts but not in hearts from catecholamine-depleted rats (ventricular fibrillation duration, 110 +/- 19 versus 0 +/- 0 seconds). The addition of thrombin or TRAP(1-6) increased arrhythmias in catecholamine-depleted hearts (112 +/- 32 and 89 +/- 28 seconds, respectively). Gentamicin and U-73122 but not U-73343 prevented thrombin-induced arrhythmias. Gentamicin inhibited norepinephrine-initiated arrhythmias, but U-73122 was ineffective.

CONCLUSIONS

This study demonstrates that the development of reperfusion arrhythmias under these conditions depends on the release of Ins(1,4,5)P3.

摘要

背景

心脏再灌注通过去甲肾上腺素对α1 - 肾上腺素能受体的刺激引发肌醇1,4,5 - 三磷酸[Ins(1,4,5)P3]的释放和心律失常的发生。本研究检测在此条件下凝血酶刺激的Ins(1,4,5)P3释放所产生的致心律失常作用。

方法与结果

通过高效液相色谱法测定[3H]肌醇标记的大鼠心脏中[3H]Ins(1,4,5)P3的释放。在缓冲液灌注的大鼠心脏中进行心律失常研究。全心缺血20分钟后再灌注2分钟，使[3H]Ins(1,4,5)P3从1123±77增加至2238±44 cpm/mg组织。在去甲肾上腺素耗竭的心脏中未观察到增加（755±89 cpm/mg）。添加凝血酶（5 IU/mL）或凝血酶受体激动肽（TRAP(1 - 6)，50 μmol/L）可恢复再灌注时Ins(1,4,5)P3的反应（凝血酶，1518±68 cpm/mg；TRAP(1 - 6)，1755±128 cpm/mg）。庆大霉素（150 μmol/L）可抑制去甲肾上腺素或凝血酶引发的Ins(1,4,5)P3释放（分别为986±52和868±125 cpm/mg）。凝血酶反应可被磷脂酶C抑制剂U - 73122（5 μmol/L；394±59 cpm/mg）抑制，但不能被其无活性异构体U - 73343抑制。去甲肾上腺素反应不受U - 73122抑制（2126±74 cpm/mg）。在完整心脏中观察到室性心动过速和心室颤动，但在去甲肾上腺素耗竭的大鼠心脏中未观察到（心室颤动持续时间，110±19秒对0±0秒）。添加凝血酶或TRAP(1 - 6)可增加去甲肾上腺素耗竭心脏中的心律失常（分别为112±32秒和89±28秒）。庆大霉素和U - 73122可预防凝血酶诱导的心律失常，但U - 73343无效。庆大霉素可抑制去甲肾上腺素引发的心律失常，但U - 73122无效。