Bourreau J P
Department of Physiology, University of Hong Kong.
Biol Signals. 1993 Sep-Oct;2(5):272-83. doi: 10.1159/000109508.
In smooth muscle, contractions under pharmacomechanical and electromechanical coupling mechanism control rely on mobilization of intracellular calcium and on calcium influx from the extracellular space, respectively. In airway smooth muscle, pharmacomechanical coupling seems to predominate. Even if extracellular calcium enters the cell during agonist stimulation, and contributes to the maintained plateau phase of a prolonged stimulation-induced contraction, it does not result from membrane depolarization and is not part of the electromechanical coupling mechanism. Pharmacomechanical and electromechanical coupling are most likely not independent processes: we present here an example of cross talk between plasma membrane and sarcoplasmic reticulum, which results in an almost complete switch in the E-C coupling process from pharmaco- to electromechanical mode in tracheal smooth muscle.
在平滑肌中，药物机械偶联和机电偶联机制控制下的收缩分别依赖于细胞内钙的动员和细胞外空间钙的内流。在气道平滑肌中，药物机械偶联似乎占主导地位。即使在激动剂刺激期间细胞外钙进入细胞，并有助于延长刺激诱导收缩的持续平台期，但它并非由膜去极化引起，也不是机电偶联机制的一部分。药物机械偶联和机电偶联很可能不是独立的过程：我们在此展示了一个质膜与肌浆网之间相互作用的例子，这导致气管平滑肌中兴奋 - 收缩偶联过程几乎完全从药物机械模式转变为机电模式。
