Nicholl Peter A, Howlett Susan E
Department of Pharmacology, Dalhousie University, Halifax, NS, B3H 1X5, Canada.
Can J Aging. 2006 Spring;25(1):107-13. doi: 10.1353/cja.2006.0026.
Whether the density of sarcoplasmic reticulum (SR) calcium release channels/ryanodine receptors in the heart declines with age is not clear. We investigated age-related changes in the density of [3H]-ryanodine receptors in crude ventricular homogenates, which contained all ligand binding sites in heart and in isolated junctional SR membranes. Experiments utilized young (120 days) and older adult (300 days) hamsters. [3H]-ryanodine binding site density did not change with age in crude homogenate preparations, although total heart protein concentration increased significantly with age. In contrast, the density of [3H]-ryanodine binding sites decreased markedly in heavy SR membranes purified from older hearts. These results show that demonstration of age-related changes in cardiac ryanodine receptor density depends upon the preparation used. Furthermore, the increase in total ventricular protein with age suggests that normalization of data by membrane protein should be used with caution in studies of aging heart.
心肌肌浆网（SR）钙释放通道/雷诺丁受体的密度是否会随年龄增长而下降尚不清楚。我们研究了粗制心室匀浆中[3H] - 雷诺丁受体密度的年龄相关变化，粗制心室匀浆包含心脏中的所有配体结合位点以及分离出的连接肌浆网膜中的配体结合位点。实验使用了年轻（120天）和成年老年（300天）仓鼠。在粗制匀浆制剂中，[3H] - 雷诺丁结合位点密度并未随年龄变化，尽管全心总蛋白浓度随年龄显著增加。相比之下，从老年心脏纯化的重肌浆网膜中，[3H] - 雷诺丁结合位点密度显著降低。这些结果表明，心脏雷诺丁受体密度与年龄相关变化的证明取决于所使用的制剂。此外，心室总蛋白随年龄增加表明，在衰老心脏研究中，按膜蛋白对数据进行归一化处理时应谨慎使用。
