Kasai M
J Biochem. 1976 May;79(5):1067-76. doi: 10.1093/oxfordjournals.jbchem.a131148.
Ca2& incorporated in vesicles of sarcoplasmic reticulum fragments (SRF) by diffusion could be released rapidly by changing the ionic environment, by dilution from methanesulfonate (MS) to chloride. This ion exchange is considered to make the membrane potential of SRF inside-negative. Much faster release of Ca2t was also observed upon osmotic change from high to low. These responses were very similar to the Ca2& release from SRF after take up using ATP, but the release rate was slow in the case of anion exchnage. The behavior of K&, Na&, sucrose, and inulin incorporated in SRF was followed upon similar treatment. These ions and nolecules were not released upon ion exchange, but were immediately released by osomtic treatment. Therefore, the Ca& release upon anion exchange was not due to the bursting of SRF, but to a direct effect such as a membrane potential change of the SRF. The behavior of anion such as C1- and propionate could not followed by the same method because of the large permability of these anions. It was also shown that Ca& release upon ion exchange was not a direct effect of pH change. Liver microsomes did not show Ca& release upon the same treatment as SRF.
通过扩散结合到肌浆网片段（SRF）囊泡中的Ca2+，可以通过改变离子环境，即从甲磺酸盐（MS）稀释到氯化物，而迅速释放。这种离子交换被认为使SRF的膜电位呈内负性。在渗透压从高到低变化时，也观察到Ca2+释放得更快。这些反应与使用ATP摄取后SRF释放Ca2+非常相似，但在阴离子交换的情况下释放速率较慢。在类似处理下，追踪了结合在SRF中的K+、Na+、蔗糖和菊粉的行为。这些离子和分子在离子交换时不释放，但在渗透处理时立即释放。因此，阴离子交换时的Ca2+释放不是由于SRF破裂，而是由于诸如SRF膜电位变化等直接效应。由于这些阴离子的通透性大，无法用相同方法追踪Cl-和丙酸盐等阴离子的行为。还表明，离子交换时的Ca2+释放不是pH变化的直接效应。肝微粒体在与SRF相同的处理下未显示Ca2+释放。
