Walker L C, Rance N E, Price D L, Young W S
Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2181.
J Comp Neurol. 1991 Jan 1;303(1):113-20. doi: 10.1002/cne.903030110.
Galanin, a 29-amino acid peptide, has been shown by immunocytochemistry to occur in most large acetylcholinergic neurons of the complex that includes the nucleus basalis of Meynert and the nucleus of the diagonal band of Broca in nonhuman primates. In contrast, several studies have reported that most large neurons of the human nucleus basalis of Meynert complex appear to lack galanin immunoreactivity. We investigated this apparent species-difference by hybridization histochemistry for galanin messenger ribonucleic acid (mRNA) in humans and baboons. The results confirm previous immunocytochemical data; very few large neurons of the nucleus basalis of Meynert complex in humans contained detectable galanin messenger RNA, whereas most such cells in baboons were labeled by the oligodeoxynucleotide probe. The few labeled neurons in humans were primarily medial or ventral to the main body of the nucleus basalis of Meynert and corresponded in location to a minor population of relatively intensely labeled cells in baboons. These findings indicate that the indetectability of immunoreactive galanin in most cells of the nucleus basalis of Meynert complex in humans is due to a paucity or an absence of galanin messenger RNA and not to differences in posttranslational processing or transport of the peptide. Inasmuch as the probe labeled neurons in several other nuclei of both species, it is unlikely that differences in galanin messenger RNA sequences underlie the species-related disparity in hybridization in the nucleus basalis of Meynert complex. The indetectability of galanin messenger RNA in most cells of the human nucleus basalis of Meynert complex indicates that the expression of the galanin gene is regulated by as yet unidentified influences that differ in human and nonhuman primates. The varying phenotypes of galanin in primates suggest potentially important species-differences in the function of galanin in neurons of the nucleus basalis of Meynert complex.
甘丙肽是一种由29个氨基酸组成的肽，免疫细胞化学研究表明，在非人类灵长类动物中，它存在于包括迈内特基底核和布罗卡斜角带核在内的复合体的大多数大型乙酰胆碱能神经元中。相比之下，多项研究报告称，人类迈内特基底核复合体的大多数大型神经元似乎缺乏甘丙肽免疫反应性。我们通过对人类和狒狒的甘丙肽信使核糖核酸（mRNA）进行杂交组织化学研究，来探究这种明显的物种差异。结果证实了先前的免疫细胞化学数据；人类迈内特基底核复合体中很少有大型神经元含有可检测到的甘丙肽信使核糖核酸，而狒狒的大多数此类细胞都被寡脱氧核苷酸探针标记。人类中少数被标记的神经元主要位于迈内特基底核主体的内侧或腹侧，其位置与狒狒中一小部分标记相对强烈的细胞相对应。这些发现表明，人类迈内特基底核复合体大多数细胞中免疫反应性甘丙肽的不可检测性是由于甘丙肽信使核糖核酸的缺乏或缺失，而不是由于该肽的翻译后加工或运输存在差异。鉴于该探针标记了两个物种其他几个核中的神经元，迈内特基底核复合体杂交中与物种相关的差异不太可能是由甘丙肽信使核糖核酸序列差异造成的。人类迈内特基底核复合体大多数细胞中甘丙肽信使核糖核酸的不可检测性表明，甘丙肽基因的表达受尚未明确的影响因素调控，这些因素在人类和非人类灵长类动物中有所不同。灵长类动物中甘丙肽的不同表型表明，甘丙肽在迈内特基底核复合体神经元中的功能可能存在重要的物种差异。
