Vescovo G, Harding S E, Jones S M, Dalla Libera L, Pessina A C, Poole-Wilson P A
National Heart and Lung Institute, London, England.
Basic Res Cardiol. 1989 Sep-Oct;84(5):536-43. doi: 10.1007/BF01908205.
The contractile properties of single rat cardiac cells isolated from normal and hypertrophied right ventricles have been investigated. These have been correlated with the isoenzyme composition of the whole ventricle. Right cardiac hypertrophy was induced by injecting rats with monocrotaline, an alkaloid which induces severe pulmonary hypertension. Ca2+ ATPase activity and myosin alpha-chain percentage were decreased in the hypertrophied right ventricle as compared with that of control rats. The contraction amplitude and speed of shortening of the isolated cells were measured using an inverted microscope, video camera, and edge detection device. Cells from the hypertrophied ventricle showed a significantly decreased contraction amplitude and speed of shortening in maximally activating concentrations of isoprenaline. A statistically significant correlation existed between myosin alpha-chain percentage and both contraction amplitude and speed of shortening in maximum isoprenaline. This was true when all cells studied were included, as well as within the hypertrophy group. A similar, although not always statistically significant, correlation was observed when cells were maximally activated with calcium. These results suggest that changes in isomyosin pattern that occur in cardiac hypertrophy produce alterations in contraction amplitude and speed of shortening which can be detected in single cells isolated from the hypertrophied ventricles. Isolated cells appear to give responses representative of the function of the whole heart.
对从正常和肥大的右心室分离出的单个大鼠心肌细胞的收缩特性进行了研究。这些特性已与整个心室的同工酶组成相关联。通过给大鼠注射可导致严重肺动脉高压的生物碱野百合碱来诱导右心肥大。与对照大鼠相比，肥大的右心室中Ca2+ ATP酶活性和肌球蛋白α链百分比降低。使用倒置显微镜、摄像机和边缘检测装置测量分离细胞的收缩幅度和缩短速度。来自肥大心室的细胞在最大激活浓度的异丙肾上腺素作用下，收缩幅度和缩短速度显著降低。在最大异丙肾上腺素作用下，肌球蛋白α链百分比与收缩幅度和缩短速度之间存在统计学上的显著相关性。当纳入所有研究的细胞以及肥大组内时都是如此。当用钙将细胞最大程度激活时，观察到类似的相关性，尽管并不总是具有统计学意义。这些结果表明，心脏肥大时发生的异肌球蛋白模式变化会导致收缩幅度和缩短速度改变，这可以在从肥大心室分离出的单个细胞中检测到。分离的细胞似乎给出了代表全心功能的反应。
