Padua R A, Wan W H, Nagy J I, Geiger J D
Department of Physiology, University of Manitoba, Faculty of Medicine, Winnipeg, Canada.
Brain Res. 1991 Feb 22;542(1):135-40. doi: 10.1016/0006-8993(91)91007-n.
High affinity [3H]ryanodine binding sites were characterized in P1 (crude nuclear), P2 (mitochondrial/synaptosomal) and P3 (microsomal) subcellular fractions of rat brain. Binding in each of the fractions was highest at 37 degrees C and pH 8-9, optimal in the presence of 100 microM Ca2+, 550 microM ATP and 1.0 M KCl, and increased linearly as a function of protein. Saturation analyses revealed a single class of binding sites with mean KD values (nM) of 8.9, 1.6 and 5.7 and Bmax values (fmol/mg protein) of 122, 69 and 106 for the P1, P2 and P3 fractions, respectively. The levels of [3H]ryanodine binding in P1 and P2 fractions of 4 brain regions were fairly uniform while those in P3 fractions were 5-fold greater in cerebral cortex than in the other areas examined. By autoradiography, a high concentration of [3H]ryanodine binding sites was seen in the dentate gyrus and CA3 subregions of the hippocampus. The results suggest that [3H]ryanodine binding sites, perhaps similar to [3H]ryanodine receptors in muscle, are associated with various subcellular structures and are heterogeneously distributed in the CNS.
在大鼠脑的P1（粗核）、P2（线粒体/突触体）和P3（微粒体）亚细胞组分中对高亲和力[3H]雷诺丁结合位点进行了表征。各组分中的结合在37℃和pH 8 - 9时最高，在100 microM Ca2+、550 microM ATP和1.0 M KCl存在下最佳，并且随蛋白质含量呈线性增加。饱和分析显示，P1、P2和P3组分分别有一类结合位点，其平均KD值（nM）为8.9、1.6和5.7，Bmax值（fmol/mg蛋白质）为122、69和106。4个脑区的P1和P2组分中[3H]雷诺丁结合水平相当均匀，而P3组分中，大脑皮层的结合水平比其他检查区域高5倍。通过放射自显影，在海马体的齿状回和CA3亚区域可见高浓度的[3H]雷诺丁结合位点。结果表明，[3H]雷诺丁结合位点可能类似于肌肉中的[3H]雷诺丁受体，与各种亚细胞结构相关，并且在中枢神经系统中呈异质性分布。
