von Bohlen und Halbach Oliver, Unsicker Klaus
Interdisciplinary Center for Neuroscience (IZN), Department of Neuroanatomy, University of Heidelberg, Im Neuenheimer Feld 307, 69120 Heidelberg, Germany.
Cell Tissue Res. 2003 Feb;311(2):139-43. doi: 10.1007/s00441-002-0662-4. Epub 2002 Dec 4.
Numbers of catecholaminergic neurons are known to decline with aging. Whether projections of these neurons to the forebrain are similarly affected is not known. High densities of tyrosine hydroxylase-immunoreactive (TH-ir) fibers are found in the hippocampal formation (CA1-3, dentate gyrus) and in the amygdala of normal adult mice. We report here that densities of TH-ir fibers in the amygdala and hippocampus in aged mice (21-26 months) decrease dramatically and in a subregion-specific fashion. There is a reduction of 35% in the dentate gyrus, while hippocampal regions CA1 through CA3 are almost entirely spared. In the amygdala the lateral, basolateral, basomedial, and central nucleus were affected, with fiber reduction ranging from 19% to 34%. These results indicate that the age-related decline of TH-ir catecholaminergic cell bodies in the substantia nigra and the ventral tegmental area induces substantial losses of TH-ir fibers in the amygdala and dentate gyrus, but not in other areas of the hippocampal formation. This suggests that region-specific factors may be implicated in the regulation of maintenance vs. degeneration of TH-ir fibers during aging.
已知儿茶酚胺能神经元的数量会随着衰老而减少。这些神经元向前脑的投射是否也受到类似影响尚不清楚。在正常成年小鼠的海马结构（CA1 - 3、齿状回）和杏仁核中发现了高密度的酪氨酸羟化酶免疫反应性（TH-ir）纤维。我们在此报告，老年小鼠（21 - 26个月）杏仁核和海马中TH-ir纤维的密度显著降低，且呈亚区域特异性方式。齿状回中减少了35%，而海马区域CA1至CA3几乎完全未受影响。在杏仁核中，外侧核、基底外侧核、基底内侧核和中央核受到影响，纤维减少幅度在19%至34%之间。这些结果表明，黑质和腹侧被盖区中与年龄相关的TH-ir儿茶酚胺能细胞体的减少，会导致杏仁核和齿状回中TH-ir纤维大量减少，但海马结构的其他区域则不然。这表明区域特异性因素可能与衰老过程中TH-ir纤维的维持与退化的调节有关。
