Impaired cell shortening and relengthening with increased pacing frequency are intrinsic to the senescent mouse cardiomyocyte
Impaired cell shortening and relengthening with increased pacing frequency are intrinsic to the senescent mouse cardiomyocyte
复制标题
DOI：
10.1006/jmcc.2000.1239
复制
发表时间：
2000-11-01
影响因子：
5
通讯作者：
Liao, RL
中科院分区：
文献类型：
--
作者：
Lim, CC;Apstein, CS;Liao, RL
心率增加可增强心脏收缩力并加速放松。力-和弛豫-频率关系对心肌功能至关重要，特别是在应激期间，并且已被证明在衰老心肌中受损。虽然衰老心肌的特点是肌浆网钙ATP酶活性降低，但目前还不清楚钙调节的改变是否直接导致老年心肌收缩力减弱和舒张，随着起搏频率的增加，我们使用新鲜分离的左心室肌细胞从年轻成年人和衰老小鼠心脏中分离出来，研究了这个问题。将心肌细胞在37 ℃下从2 Hz起搏至9 Hz，并分别使用视频边缘检测和fura-2荧光同时测量细胞缩短和[Ca 2 +]（i）。在成年心肌细胞中，增加起搏频率导致细胞缩短百分比（CS）进行性增加（P
Increased heart rate enhances cardiac contractility and accelerates relaxation. Both the force- and relaxation-frequency relationships are critical to myocardial function, especially during stress, and have been shown to be impaired in senescent myocardium. While senescent myocardium is characterized by decreased sarcoplasmic reticulum calcium ATPase activity it is unclear if altered calcium regulation is directly responsible for the attenuated contractility and relaxation observed with increasing pacing frequency in aged myocardium.We examined this issue using freshly dissociated left ventricular myocytes, isolated from young adult and senescent mouse hearts. Myocytes were paced from 2 to 9 Hz at 37 degreesC, and cell shortening and [Ca2+](i) were simultaneously measured using video edge-detection and fura-2 fluorescence, respectively. In adult myocytes, increasing the pacing rate resulted in a progressive increase in percent cell shortening (CS) (P