Impaired Ca2+ handling is an early manifestation of pressure-overload hypertrophy in rat hearts.
Impaired Ca2+ handling is an early manifestation of pressure-overload hypertrophy in rat hearts.
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Ca2 处理受损是大鼠心脏压力超负荷肥大的早期表现。
DOI：
10.1152/ajpheart.1996.271.1.h228
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Camacho,SA
中科院分区：
文献类型：
--
作者：
Chang,KC;Schreur,JH;Weiner,MW;Camacho,SA
心肌细胞内游离Ca ~（2+）（[Ca ~（2+）]i）下降和心肌舒张在严重肥厚和心力衰竭时均减慢。然而，尚不确定这是否发生在轻度至中度肥大中。因此，我们测试了以下假设：[Ca 2 +]i下降的减缓1）发生在轻度至中度肥大中，2）发生在没有舒张减慢的情况下，3）与肥大程度有关。在压力超负荷的离体大鼠心脏上进行实验。Indo 1荧光作为[Ca 2 +]i的指标。[Ca2分别用[Ca 2 +]i指数下降时间常数（Tau Ca）和左心室（LV）压力下降时间常数（Tau p）评价心肌舒张和[Ca 2 +]i下降。与假手术大鼠相比，结扎大鼠心脏中的平均tau Ca显著增加（59 +/- 13 vs. 45 +/- 5 ms，P = 0.03）。相比之下，平均tau p无差异（28 +/- 3 vs. 29 +/- 5 ms，P =不显著）。Tau Ca与左室干重呈线性关系（r = 0.79）。总之，轻度至中度肥大患者[Ca 2 +]i一过性下降减缓。然而，LV舒张未受影响。此外，[Ca 2 +]i短暂下降的减缓与LV肥大的程度密切相关。这些数据表明，[Ca 2 +]i下降的减缓是压力超负荷性肥大的早期表现，先于松弛的减缓。
Both cytosolic free Ca2+ ([Ca2+]i) decline and myocardial relaxation are slowed in severe hypertrophy and heart failure. However, it is not certain whether this occurs in mild to moderate hypertrophy. Therefore, we tested the hypotheses that slowing of [Ca2+]i decline 1) occurs in mild to moderate hypertrophy, 2) occurs in the absence of slowed relaxation, and 3) is related to the degree of hypertrophy. Experiments were performed on isolated rat hearts subjected to pressure overload. Indo 1 fluorescence was used as an index of [Ca2+]i. [Ca2+]i decline and myocardial relaxation were assessed by the time constant of exponential [Ca2+]i decline (tau Ca) and left ventricular (LV) pressure decline (tau p), respectively. Mean tau Ca was significantly increased in hearts from banded rats compared with sham-operated rats (59 +/- 13 vs. 45 +/- 5 ms, P = 0.03). In contrast, there was no difference in mean tau p (28 +/- 3 vs. 29 +/- 5 ms, P = not significant). There was a linear relationship between tau Ca and LV dry weight (r = 0.79). In summary, slowing of the [Ca2+]i transient decline occurred in mild to moderate hypertrophy. However, LV relaxation was unaffected. Furthermore, slowing of the [Ca2+]i transient decline was closely related to the degree of LV hypertrophy. These data suggest that slowing of [Ca2+]i decline is an early manifestation of pressure-overload hypertrophy that precedes slowing of relaxation.