Heiny J A, Jong D, Bryant S H, Conte-Camerino D, Tortorella V
Department of Physiology and Biophysics, University of Cincinnati, Ohio 45267-0576.
Biophys J. 1990 Jan;57(1):147-52. doi: 10.1016/S0006-3495(90)82515-7.
Aromatic monocarboxylic acids are known to significantly potentiate the mechanical response of skeletal muscle fibers. In this study we investigated the effects of enantiomers of 2-(4-chlorophenoxy)propionic acid, chemically one of the simplest aromatic monocarboxylic acids with chiral properties, on mechanical threshold and charge movement in frog skeletal muscle. The R(+), but not the S(-), enantiomer lowered rheobase mechanical threshold and shifted charge movement to more negative potentials. The R(+) enantiomer also significantly slowed charge movement kinetics, with pronounced delays of the OFF charge transitions. These effects required high temperature for their production. The stereospecific actions of the R(+) enantiomer are interpreted in terms of a specific interaction of this compound at an anion-sensitive site involved in excitation-contraction coupling, most likely on the dihydropryidine-sensitive voltage sensor in the T-system.
已知芳香族一元羧酸能显著增强骨骼肌纤维的机械反应。在本研究中，我们研究了2-(4-氯苯氧基)丙酸（化学上是最简单的具有手性性质的芳香族一元羧酸之一）的对映体对青蛙骨骼肌机械阈值和电荷移动的影响。R(+)对映体而非S(-)对映体降低了基强度机械阈值，并使电荷移动向更负的电位偏移。R(+)对映体还显著减慢了电荷移动动力学，OFF电荷转变有明显延迟。这些效应需要高温才能产生。R(+)对映体的立体特异性作用可通过该化合物在参与兴奋-收缩偶联的阴离子敏感位点上的特异性相互作用来解释，最有可能是在T系统中对二氢吡啶敏感的电压传感器上。
