脑缺血引发心肌收缩功能和细胞内钙处理异常。

Cerebral ischemia elicits aberration in myocardium contractile function and intracellular calcium handling.

作者信息

Sun Lihua, Ai Jing, Wang Ning, Zhang Rong, Li Jingyuan, Zhang Tianzhu, Wu Wanchen, Hang Pengzhou, Lu Yanjie, Yang Baofeng

机构信息

Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), Harbin Medical University, Harbin, China.

出版信息

Cell Physiol Biochem. 2010;26(3):421-30. doi: 10.1159/000320584. Epub 2010 Aug 25.

Abstract

The mechanisms of myocardial dysfunction and calcium handling disturbance underlying cerebral ischemia remain obscure. Here we for the first time report that acute cerebral ischemia significantly increased left ventricular end diastolic pressure (LVEDP), but decreased +dP/dt, -dP/dt, and left ventricular systolic pressure (LVSP). Significant increase in either the resting or KCl-induced Ca2+in ventricular myocytes was also detected by scanning confocal microscopy at 2 and 24 hours after cerebral ischemia. Verapamil as a blocker of I(Ca,L), ryanodine as a specific inhibitor of RyR, thapsigargin as a highly specific inhibitor of sarco(endo)plasmic reticulum Ca(2+)-ATPase 2a (SERCA2a) and SEA0400 as a selective NCX inhibitor changed the area under the curve of averaged ratio of fluorescence (FI/F(0)I) induced by KCl. Cardiac expression of Ca(v)1.2 was significantly up-regulated at 2 and 24 hours after cerebral ischemia, whereas cardiac expression of SERCA2a and Na(+)-Ca(2+) exchanger (NCX) was significantly down-regulated at the same time period after cerebral ischemia. Cardiac expression of phospholamban (PLB) was significantly elevated at 2 hours after cerebral ischemia but was restored to about normal level at 24 hours after injury. These data suggest that acute cerebral ischemia may specifically disturb cardiac function and calcium homeostasis, which are related to increase of Ca(v)1.2 and decrease of through up-regulating Ca(v)1.2 and PLB, down-regulating SERCA2a and NCX, subsequently leading to Ca2+ overload by the enhancement of Ca2+ influx and inhibition of intracellular Ca2+ extrusion and cerebral ischemia-induced myocardial dysfunction.

摘要

脑缺血导致心肌功能障碍和钙处理紊乱的机制仍不清楚。在此,我们首次报道急性脑缺血显著增加左心室舒张末期压力(LVEDP),但降低 +dP/dt、-dP/dt 和左心室收缩压(LVSP)。脑缺血后 2 小时和 24 小时,通过扫描共聚焦显微镜还检测到心室肌细胞静息或氯化钾诱导的 Ca2+ 显著增加。维拉帕米作为 L 型钙通道(I(Ca,L))阻滞剂、ryanodine 作为兰尼碱受体(RyR)特异性抑制剂、毒胡萝卜素作为肌浆网 Ca(2+)-ATP 酶 2a(SERCA2a)高度特异性抑制剂以及 SEA0400 作为选择性钠钙交换体(NCX)抑制剂,均改变了氯化钾诱导的荧光平均比值(FI/F(0)I)曲线下面积。脑缺血后 2 小时和 24 小时,Ca(v)1.2 的心脏表达显著上调,而同一时间段内 SERCA2a 和钠钙交换体(NCX)的心脏表达显著下调。脑缺血后 2 小时,受磷蛋白(PLB)的心脏表达显著升高,但损伤后 24 小时恢复至正常水平。这些数据表明,急性脑缺血可能特异性地扰乱心脏功能和钙稳态,这与 Ca(v)1.2 的增加以及通过上调 Ca(v)1.2 和 PLB、下调 SERCA2a 和 NCX 导致的钙超载有关,随后通过增强 Ca2+ 内流和抑制细胞内 Ca2+ 外流导致脑缺血诱导的心肌功能障碍。

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