Whole-cell mechanosensitive currents in rat ventricular myocytes activated by direct stimulation
Whole-cell mechanosensitive currents in rat ventricular myocytes activated by direct stimulation
复制标题
DOI：
10.1007/s002320001024
复制
发表时间：
2000-02-01
影响因子：
2.4
通讯作者：
Sachs, F
中科院分区：
文献类型：
--
作者：
Bett, GCL;Sachs, F
机械敏感性通道可能在梗死后心律失常的发展中起重要作用，但细胞水平上的机械反应数据有限。机械敏感性是细胞的普遍属性，虽然细菌机械敏感离子通道的结构是已知的克隆，在真核生物的结构和力转导通路仍然habitu.Isolated成年大鼠心室肌细胞电压钳和刺激与机械探针。将探针设置为正弦运动（在细胞膜平面内或垂直于细胞膜平面），然后缓慢降低到细胞上。正弦频率保持恒定在1 Hz，但刺激幅度增加，探针逐渐降低，直到观察到机械敏感的全细胞电流，其通常在刺激几分钟后出现。大鼠细胞中的全细胞机械敏感电流有两个组成部分：（i）短暂的大内向电流尖峰电流;（ii）更持续的较小内向电流。最初的急剧内向电流的存在表明细胞内的某些结构松弛或被破坏，使机械敏感元件暴露于应力。在机械敏感性反应之前由持续应力诱导的代谢变化可能会削弱产生尖峰的断裂元件，或者可能发生细胞骨架本身的简单应力诱导断裂。
Mechanosensitive channels may have a significant role in the development of cardiac arrhythmia following infarction, but the data on mechanical responses at the cellular level are limited. Mechanosensitivity is a ubiquitous property of cells, and although the structure of bacteriological mechanosensitive ion channels is becoming known by cloning, the structure and force transduction pathway in eukaryotes remains elusive.Isolated adult rat ventricular myocytes were voltage clamped and stimulated with a mechanical probe. The probe was set in sinusoidal motion (either in, or normal to, the plane of the cell membrane), and then slowly lowered onto the cell. The sinusoidal frequency was held constant at 1 Hz but the stimulation amplitude was increased and the probe gradually lowered until a mechanically sensitive whole cell current was seen, which usually followed several minutes of stimulation.The whole cell mechanosensitive current in rat cells had two components: (i) a brief large inward current spike current; (ii) a more sustained smaller inward current. The presence of the initial sharp inward current suggests that some structure within the cell either relaxes or is broken, exposing the mechanosensitive element(s) to stress. Metabolic changes induced by continued stress prior to the mechanosensitive response may weaken the elements that break producing the spike, or simple stress-induced fracture of the cytoskeleton itself may occur.