Ca2+ transient decline and myocardial relaxation are slowed during low flow ischemia in rat hearts.
Ca2+ transient decline and myocardial relaxation are slowed during low flow ischemia in rat hearts.
复制标题
大鼠心脏低流量缺血期间，Ca2 瞬时下降和心肌舒张减慢。
DOI：
10.1172/jci117101
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Weiner,MW
中科院分区：
文献类型：
--
作者：
Camacho,SA;Brandes,R;Figueredo,VM;Weiner,MW
缺血时损害心肌舒张的机制被认为与钙处理异常有关。然而，几乎没有直接证据支持这一假设。因此，我们试图确定低流量缺血时胞质钙（[Ca2+]c）下降时间常数（tau Ca）是否增加，以及左心室压下降时间常数（tau P）与tau Ca之间是否存在关系。用吲哚-1荧光比作为[Ca2+]c的指标对离体灌注心脏进行了研究。以tau P作为心肌舒张指标。当冠状动脉血流减少时，indo-1比值下降的时间常数分别从74 +/- 5 ms增加到95 +/- 4、144 +/- 10和204 +/- 16 ms，分别减少到对照组的50%、20%和10%。校正Indo-1瞬态以计算tau Ca。当冠状动脉血流分别减少到对照组的20%和10%时，tau Ca分别从67 +/- 6 ms增加到108 +/- 9和158 +/- 19 ms。tau Ca与tau P呈线性关系（r = 0.82）。这些数据支持低流量缺血时心肌舒张受损可能由[Ca2+]c下降减慢引起的假设。
The mechanisms that impair myocardial relaxation during ischemia are believed to involve abnormalities of calcium handling. However, there is little direct evidence to support this hypothesis. Therefore, we sought to determine whether the time constant of cytosolic calcium ([Ca2+]c) decline (tau Ca) was increased during low flow ischemia, and if there was a relationship between the time constant of left ventricular pressure decline (tau P) and tau Ca. Isolated perfused hearts were studied using indo-1 fluorescence ratio as an index of [Ca2+]c.tau P was used as an index of myocardial relaxation. The time constant of decline of the indo-1 ratio increased from 74 +/- 5 ms to 95 +/- 4, 144 +/- 10, and to 204 +/- 16 ms when coronary flow was reduced was reduced to 50, 20, and 10% of control, respectively. Indo-1 transients were calibrated to calculate tau Ca. tau Ca increased from 67 +/- 6 ms to 108 +/- 9 and 158 +/- 19 ms when coronary flow was reduced to 20 and 10% of control, respectively. There was a linear relationship between tau Ca and tau P (r = 0.82). These data support the hypothesis that during low flow ischemia, impaired myocardial relaxation may be caused by slowing of [Ca2+]c decline.