Woo Sun-Hee, Risius Tim, Morad Martin
College of Pharmacy, Chungnam National University, 220 Gung-Dong, Daejeon 305-764, South Korea.
Cell Calcium. 2007 Apr;41(4):397-403. doi: 10.1016/j.ceca.2006.09.005. Epub 2006 Nov 7.
Atrial myocytes that lack t-tubules appear to have two functionally separate sarcoplasmic Ca2+ stores: a peripheral store associated with plasmalemmal L-type calcium channels and a central store with no apparent proximity to L-type calcium channels. Here we describe a set of calcium sparks and waves that are triggered by puffing of pressurized (200-400 mmH2O) bathing solutions onto resting isolated rat atrial myocytes. Puffing of pressurized (200 mmH2O) solutions, identical to those bathing the myocytes from distances of approximately 150 microm onto the surface of a single myocyte triggered or enhanced spontaneously occurring peripheral sparks by five- to six-fold and central Ca2+ sparks by two- to three-fold, without altering the unitary spark properties. Exposure to higher pressure flows (400 mmH2O) often triggered longitudinally spreading Ca2+ waves. These results suggest that pressurized flows may directly modulate Ca2+ signaling of atrial myocytes by activating the intracellular Ca2+ release sites.
缺乏横管的心房肌细胞似乎有两个功能上独立的肌浆网Ca2+储存库：一个与质膜L型钙通道相关的外周储存库和一个与L型钙通道无明显接近关系的中央储存库。在此，我们描述了一组钙火花和钙波，它们是通过将加压（200 - 400 mmHg2O）的浴液吹到静息的离体大鼠心房肌细胞上而触发的。将与从约150微米距离处浴洗肌细胞的溶液相同的加压（200 mmHg2O）溶液吹到单个肌细胞表面，可使自发出现的外周火花触发或增强五到六倍，中央Ca2+火花增强两到三倍，而不改变单个火花的特性。暴露于更高压力流（400 mmHg2O）通常会触发纵向传播的Ca2+波。这些结果表明，加压流可能通过激活细胞内Ca2+释放位点直接调节心房肌细胞的Ca2+信号传导。
