锌离子对鱼鳃细胞通透化后线粒体和内质网摄取钙离子的影响。

Effects of Zn(2+) on Ca (2+) uptake by mitochondria and endoplasmic reticulum in permeabilized tilapia gill cells.

机构信息

Department of Animal Physiology, Faculty of Science, University of Nijmegen, Toernooiveld 1, NL-6525-ED, Nijmegen, The Netherlands.

出版信息

Fish Physiol Biochem. 1996 Aug;15(4):299-305. doi: 10.1007/BF02112356.

DOI:10.1007/BF02112356

PMID:24194248

Abstract

An intracellular ATP-dependent Ca(2+) pumping mechanism, distinct from mitochondrial Ca(2+) accumulation, was identified within tilapia gill cells. Cell suspensions treated with 0.003% saponin, which selectively permeabilizes the plasma membrane, were used to characterize the Ca(2+) sequentering mechanisms as endoplasmic reticulum and mitochondria and to determine the effect of Zn(2+) on their Ca(2+) storing activity. Of the Ca(2+) taken up by the endoplasmic reticulum, 80% was released by IP3 (10 μmol l(-1)). The Ca(2+) pump of the endoplasmic reticulum was 2.5 times less sensitive to Zn(2+) (IC50=0.05 nmol l(-1)) than was the mitochondrial uptake mechanism (IC50=0.20 nmol l(-1)). The results indicate that Ca(2+) is stored predominantly within the endoplasmic reticulum at 0.1 μmol l(-1) and that this storing capacity is seriously attenuated by namomolar concentrations Zn(2+).

摘要

在罗非鱼鳃细胞中发现了一种细胞内依赖于 ATP 的 Ca(2+)泵机制，与线粒体 Ca(2+)积累不同。用 0.003%皂素（选择性通透质膜）处理细胞悬浮液，以表征内质网和线粒体中的 Ca(2+)顺序发生机制，并确定 Zn(2+)对其 Ca(2+)储存活性的影响。内质网摄取的 Ca(2+)中，80%被 IP3（10 μmol l(-1)）释放。内质网 Ca(2+)泵对 Zn(2+)的敏感性（IC50=0.05 nmol l(-1))比线粒体摄取机制低 2.5 倍（IC50=0.20 nmol l(-1))。结果表明，在 0.1 μmol l(-1)时，Ca(2+)主要储存在内质网中，纳摩尔浓度的 Zn(2+)严重削弱了这种储存能力。