Kelliher M, Fastbom J, Cowburn R F, Bonkale W, Ohm T G, Ravid R, Sorrentino V, O'Neill C
Department of Biochemistry, University College, Lee Maltings, Prospect Row, Cork, Ireland.
Neuroscience. 1999;92(2):499-513. doi: 10.1016/s0306-4522(99)00042-1.
Investigation of the integrity of the ryanodine receptor in Alzheimer's disease is important because it plays a critical role in the regulation of calcium release from the endoplasmic reticulum in brain, impairment of which is believed to contribute to the pathogenesis of Alzheimer's disease. The present study compared ryanodine receptor levels and their functional modulation in particulate fractions from control and Alzheimer's disease temporal cortex, occipital cortex and putamen. Relationships between ryanodine receptor changes and the progression of Alzheimer's disease pathology were determined by examining autoradiographic [3H]ryanodine binding in entorhinal cortex/anterior hippocampus sections from 22 cases that had been staged for neurofibrillary changes and beta-amyloid deposition. A significant (P < 0.02) 40% decrease in the Bmax for [3H]ryanodine binding and significantly higher IC50 values for both magnesium and Ruthenium Red inhibition of [3H]ryanodine binding were detected in Alzheimer's disease temporal cortex particulate fractions compared to controls. Immunoblot analyses showed Type 2 ryanodine receptor holoprotein levels to be decreased by 20% (P < 0.05) in these Alzheimer's disease cases compared to controls. No significant differences were detected in [3H]ryanodine binding comparing control and Alzheimer's disease occipital cortex or putamen samples. The autoradiography study detected increased [3H]ryanodine binding in the subiculum, CA2 and CA1 regions in cases with early (stage I-II) neurofibrillary pathology when compared to Stage 0 cases. Analysis of variance of data with respect to the different stages of neurofibrillary pathology revealed significant stage-related declines of [3H]ryanodine binding in the subiculum (P < 0.02) with trends towards significant decreases in CA1, CA2 and CA4. Post-hoc testing with Fisher's PLSD showed significant reductions (74-94%) of [3H]ryanodine binding in the subiculum, and CA1-CA4 regions of the late isocortical stage (V-VI) cases compared to the early entorhinal stage I-II cases. [3H]Ryanodine binding also showed significant declines with staging for beta-amyloid deposition in the entorhinal cortex (P < 0.01) and CA4 (P < 0.05) with trends towards a significant decrease in the dentate gyrus. We conclude that alterations in ryanodine receptor binding and function are very early events in the pathogenesis of Alzheimer's disease, and may be fundamental to the progression of both neurofibrillary and beta-amyloid pathologies.
研究阿尔茨海默病中兰尼碱受体的完整性很重要，因为它在调节大脑内质网钙释放中起关键作用，据信其功能受损会导致阿尔茨海默病的发病机制。本研究比较了对照组和阿尔茨海默病患者颞叶皮质、枕叶皮质及壳核微粒体部分中兰尼碱受体水平及其功能调节。通过检测22例已根据神经原纤维变化和β-淀粉样蛋白沉积进行分期的内嗅皮质/前海马体切片中的放射自显影[3H]兰尼碱结合，确定了兰尼碱受体变化与阿尔茨海默病病理进展之间的关系。与对照组相比，在阿尔茨海默病颞叶皮质微粒体部分检测到[3H]兰尼碱结合的Bmax显著降低（P < 0.02）40%，并且镁和钌红对[3H]兰尼碱结合的抑制作用的IC50值显著更高。免疫印迹分析显示，与对照组相比，这些阿尔茨海默病病例中2型兰尼碱受体全蛋白水平降低了20%（P < 0.05）。比较对照组和阿尔茨海默病枕叶皮质或壳核样本的[3H]兰尼碱结合未发现显著差异。放射自显影研究检测到，与0期病例相比，早期（I-II期）神经原纤维病理病例的海马下托、CA2和CA1区域中[3H]兰尼碱结合增加。对神经原纤维病理不同阶段的数据进行方差分析显示，海马下托中[3H]兰尼碱结合有显著的阶段相关下降（P < 0.02），CA1、CA2和CA4有下降趋势。用Fisher's PLSD进行的事后检验显示，与早期内嗅I-II期病例相比，晚期新皮质V-VI期病例的海马下托以及CA1-CA4区域中[3H]兰尼碱结合显著减少（74-94%）。[3H]兰尼碱结合也显示出随着内嗅皮质中β-淀粉样蛋白沉积的分期有显著下降（P < 0.01），在CA4中（P < 0.05），齿状回有下降趋势。我们得出结论，兰尼碱受体结合和功能的改变是阿尔茨海默病发病机制中的非常早期的事件，并且可能是神经原纤维和β-淀粉样蛋白病理进展的基础。
