Rousseau E, Pinkos J
Department of Physiology and Biophysics, Faculty of Medicine, University of Sherbrooke, Canada.
Pflugers Arch. 1990 Feb;415(5):645-7. doi: 10.1007/BF02583520.
Intracellular pH changes affect excitation-contraction coupling in skeletal and cardiac muscles. However the proton implication in modulating the sarcoplasmic reticulum Ca2+ release channel activity has never been visualized at single channel level. A large conducting Ca2+ release pathway has previously been characterized after incorporation of skeletal and cardiac sarcoplasmic reticulum vesicles into planar lipid bilayers. This channel has been activated by micromolar and millimolar concentrations of Ca2+ and ATP, respectively. The pH was independently varied on each side of the channels. Acidification of the cis-chamber (7.4 to 6.6) induced a modification of the gating behaviour, resulting in a decrease of the open probability. This effect was completely reversible. On the other hand, acidification of the trans-chamber (7.4 to 6.8) induced a reduction of the unitary conductance of the sarcoplasmic reticulum Ca2+ release channel.
细胞内pH值的变化会影响骨骼肌和心肌的兴奋-收缩偶联。然而，质子在调节肌浆网Ca2+释放通道活性中的作用从未在单通道水平上得到证实。此前，在将骨骼肌和心肌肌浆网囊泡整合到平面脂质双层后，已对一种大电导Ca2+释放途径进行了表征。该通道分别被微摩尔和毫摩尔浓度的Ca2+和ATP激活。通道两侧的pH值可独立变化。顺式腔室酸化（从7.4到6.6）会引起门控行为的改变，导致开放概率降低。这种效应是完全可逆的。另一方面，反式腔室酸化（从7.4到6.8）会导致肌浆网Ca2+释放通道的单位电导降低。
