IMMUNOLOCALIZATION OF SARCOLEMMAL DIHYDROPYRIDINE RECEPTOR AND SARCOPLASMIC RETICULAR TRIADIN AND RYANODINE RECEPTOR IN RABBIT VENTRICLE AND ATRIUM
IMMUNOLOCALIZATION OF SARCOLEMMAL DIHYDROPYRIDINE RECEPTOR AND SARCOPLASMIC RETICULAR TRIADIN AND RYANODINE RECEPTOR IN RABBIT VENTRICLE AND ATRIUM
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DOI：
10.1083/jcb.129.3.673
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发表时间：
1995-05-01
影响因子：
7.8
通讯作者：
FERGUSON, DG
中科院分区：
文献类型：
--
作者：
CARL, SL;FELIX, K;FERGUSON, DG
用免疫荧光双标记和激光共聚焦显微镜观察了成年家兔心室和心房肌细胞膜二氢吡啶受体（DHPR）、肌浆网三聚体和钙释放通道/兰尼碱受体（RyR）的亚细胞分布。在心室肌细胞中，免疫染色主要观察到沿着肌纤维全长以约2 μ m间隔分布的横向点状带。图像分析表明，几乎完全重叠的三种蛋白质的染色模式，这表明它们的密切关联或附近的二进耦合，形成的肌浆网（SR）是并列的表面膜或其内折，横（T-）小管。在兔心房细胞中，缺乏广泛的T-管系统，DHPR特异性染色被观察到形成离散点沿着肌膜，但没有从内部的纤维。在心房，点状的三聚体和RyR特异性染色也被观察到在细胞周围的斑点和图像分析表明，这三种蛋白质共定位在，或只是下面，肌膜。此外，在心房细胞triadin和RyR-特异性染色观察到形成横向带在内部细胞质中的规则间隔约2 μ m。电子显微镜检查表明，这种细胞质染色发生在大量的扩展连接SR存在的区域。这些数据表明，DHPR与Triadin和RyR在兔心室和心房中共分布，并进一步表明，在缺乏与DHPR的密切联系的情况下，心房的一些SR Ca 2+释放通道可能被激活。
The subcellular distribution of sarcolemmal dihydropyridine receptor (DHPR) and sarcoplasmic reticular triadin and Ca2+ release channel/ryanodine receptor (RyR) was determined in adult rabbit ventricle and atrium by double labeling immunofluorescence and laser scanning confocal microscopy. In ventricular muscle cells the immunostaining was observed primarily as transversely oriented punctate bands spaced at approximately 2-mu m intervals along the whole length of the muscle fibers. Image analysis demonstrated a virtually complete overlap of the staining patterns of the three proteins, suggesting their close association at or near dyadic couplings that are formed where the sarcoplasmic reticulum (SR) is apposed to the surface membrane or its infoldings, the transverse (T-) tubules. In rabbit atrial cells, which lack an extensive T-tubular system, DHPR-specific staining was observed to form discrete spots along the sarcolemma but was absent from the interior of the fibers. In atrium, punctate triadin- and RyR-specific staining was also observed as spots at the cell periphery and image analysis indicated that the three proteins were co-localized at, or just below, the sarcolemma. In addition, in the atrial cells triadin- and RyR-specific staining was observed to form transverse bands in the interior cytoplasm at regularly spaced intervals of approximately 2 mu m. Electron microscopy suggested that this cytoplasmic staining was occurring in regions where substantial amounts of extended junctional SR were present. These data indicate that the DHPR codistributes with triadin and the RyR in rabbit ventricle and atrium, and furthermore suggest that some of the SR Ca2+ release channels in atrium may be activated in the absence of a close association with the DHPR.