心脏钙释放通道的区域差异。
Regional differences in calcium-release channels from heart.
作者信息
Borgatta L, Watras J, Katz A M, Ehrlich B E
机构信息
Department of Medicine, University of Connecticut, Farmington 06030.
出版信息
Proc Natl Acad Sci U S A. 1991 Mar 15;88(6):2486-9. doi: 10.1073/pnas.88.6.2486.
The heart is a heterogeneous tissue composed of several cell types tailored for specialized functions. We found that intracellular channels also exhibit regional specialization. In cardiac and skeletal muscle these channels are called the calcium-release channel and are identified by activation with either calcium or caffeine and inhibition by the hexavalent cation ruthenium red. The calcium-release channel of the sarcoplasmic reticulum from the interventricular septum has a smaller conductance (31 pS vs. 100 pS) and has longer open and closed times when compared with the channel from left-ventricular free wall. An additional calcium-permeable channel with an even smaller conductance (17 pS) was found in the septum, and this channel is similar to the inositol 1,4,5-trisphosphate-gated channel from smooth muscle and different from the calcium-release channel (ryanodine receptor) from skeletal and cardiac muscle. The inositol 1,4,5-trisphosphate-activated channel may be derived from specialized conducting tissue that is relatively abundant in the septum, whereas the other calcium-release channels may be derived from regionally specialized myocardial cells in the septum and free wall.
心脏是一种异质性组织，由几种针对特定功能而特化的细胞类型组成。我们发现细胞内通道也表现出区域特化。在心肌和骨骼肌中，这些通道被称为钙释放通道，可通过钙或咖啡因激活以及六价阳离子钌红抑制来识别。与左心室游离壁的通道相比，室间隔肌浆网的钙释放通道电导较小（31皮西门子对100皮西门子），开放和关闭时间更长。在室间隔中发现了另一种电导更小（17皮西门子）的钙通透通道，该通道类似于平滑肌中的肌醇1,4,5-三磷酸门控通道，与骨骼肌和心肌中的钙释放通道（雷诺丁受体）不同。肌醇1,4,5-三磷酸激活通道可能源自室间隔中相对丰富的特殊传导组织，而其他钙释放通道可能源自室间隔和游离壁中区域特化的心肌细胞。
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