Department of Anatomy and Neurobiology, and Institute of Neurodegeneration and Neuroregeneration, College of Medicine, Hallym University, Chuncheon, 200-702, South Korea.
Cell Mol Neurobiol. 2010 Mar;30(2):255-63. doi: 10.1007/s10571-009-9447-6. Epub 2009 Sep 2.
Melatonin exerts many physiological functions via its G protein-coupled receptors. In the present study, we investigated age-related changes in MT2 melatonin receptor immunoreactivity and its levels in the gerbil hippocampus during normal aging. In the postnatal month 1 (PM 1) group, MT2 immunoreaction was well observed in neurons in all subregions of the gerbil hippocampus. In the PM 3 and 6 groups, MT2 immunoreactivity in neurons was decreased compared to that in the PM 1 group. Thereafter, MT2 immunoreactivity in neurons was increased. In the PM 18 and 24 groups, MT2 immunoreactivity in neurons was strong in all subregions of the gerbil hippocampus. In addition, the number of MT2 immunoreactive cells was lowest at PM 3 and highest at PM 24. From western blot analysis, age-dependent change pattern in MT2 level in the gerbil hippocampus was similar to the immunohistochemical result. These results indicate that MT2 immunoreactivity and levels are altered in the gerbil hippocampus during normal aging; lowest at young adult stage and highest at aged stage.
褪黑素通过其 G 蛋白偶联受体发挥许多生理功能。在本研究中，我们研究了正常衰老过程中年龄相关的 MT2 褪黑素受体免疫反应及其在沙鼠海马中的水平变化。在出生后 1 个月（PM1）组中，MT2 免疫反应在沙鼠海马的所有亚区的神经元中均得到很好的观察。在 PM3 和 PM6 组中，神经元中的 MT2 免疫反应性与 PM1 组相比降低。此后，神经元中的 MT2 免疫反应性增加。在 PM18 和 PM24 组中，MT2 免疫反应性在沙鼠海马的所有亚区均较强。此外，MT2 免疫反应性细胞的数量在 PM3 时最低，在 PM24 时最高。从 Western blot 分析结果可知，沙鼠海马中 MT2 水平的年龄依赖性变化模式与免疫组织化学结果相似。这些结果表明，在正常衰老过程中，MT2 免疫反应性和水平在沙鼠海马中发生改变；在年轻成年阶段最低，在老年阶段最高。
