Moon Don-Joon, Maseko Busisiwe C, Ihunwo Amadi O, Fuxe Kjell, Manger Paul R
School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, 2193 Johannesburg, Republic of South Africa.
J Chem Neuroanat. 2007 Nov;34(3-4):134-44. doi: 10.1016/j.jchemneu.2007.06.001. Epub 2007 Jun 8.
The distribution, morphology and nuclear subdivisions of the putative catecholaminergic and serotonergic systems within the brain of the highveld gerbil were identified following immunohistochemistry for tyrosine hydroxylase and serotonin. The aim of the present study was to investigate possible differences in the complement of nuclear subdivisions of these systems when comparing those of the highveld gerbil with those of the laboratory rat. The highveld gerbil was chosen as it is relatively closely related to the laboratory rat, but the Gerbillinae and Murinae lineages diverged over 20 million years ago. Moreover, even though brain sizes are similar, the life history and phenotypes between these two species are substantially different. The gerbils used in the present study were caught from the wild, which is again another contrast to the laboratory rat. While these differences may lead to the prediction of significant differences in the nuclear complement of these systems, we found that all nuclei identified in both systems in the laboratory rat in several earlier studies had direct homologs in the brain of the highveld gerbil. Moreover, there were no additional nuclei in the brain of the highveld gerbil that are not found in the laboratory rat. The only discernable difference between the two species was a greater density and number of catecholaminergic neurons in the olfactory bulb of the highveld gerbil. Thus, the evolution of nuclear parcellation in these systems appears to demonstrate a form of phylogenetic constraint related to the order Rodentia.
通过对酪氨酸羟化酶和5-羟色胺进行免疫组织化学检测，确定了高地沙鼠脑内假定的儿茶酚胺能和5-羟色胺能系统的分布、形态及核亚群。本研究的目的是比较高地沙鼠与实验大鼠这些系统的核亚群组成，研究两者可能存在的差异。选择高地沙鼠是因为它与实验大鼠亲缘关系相对较近，但绒鼠亚科和鼠亚科在2000多万年前就已分化。此外，尽管两者脑大小相似，但这两个物种的生活史和表型有很大差异。本研究中使用的沙鼠是从野外捕获的，这与实验大鼠又有所不同。虽然这些差异可能预示着这些系统的核组成存在显著差异，但我们发现，在之前的几项研究中，实验大鼠这两个系统中确定的所有核在高地沙鼠脑中都有直接的同源物。此外，高地沙鼠脑中没有在实验大鼠脑中未发现的额外核。这两个物种之间唯一可辨别的差异是高地沙鼠嗅球中儿茶酚胺能神经元的密度和数量更高。因此，这些系统中核划分的进化似乎显示出一种与啮齿目相关的系统发育限制形式。
