Vesicular monoamine transporters (VMAT) 1 and 2 are responsible for monoamine transportation into secretary vesicles and are tissue-specifically expressed in central and peripheral monoaminergic tissues, including the carotid body (CB). The aim of the present study was to examine the expression of catecholamine-synthesizing enzymes in VMAT1- and VMAT2-immunoreactive glomus cells in the rat CB using multiple immunolabeling. The expression of VMAT1 and VMAT2 mRNA in the CB was confirmed by RT-PCR. Immunohistochemistry revealed that VMAT1 immunoreactivity was predominant in glomus cells rather than VMAT2 immunoreactivity. Glomus cells with VMAT1 immunoreactivity exhibited weak/negative VMAT2 immunoreactivity, and vice versa. Immunoreactivities for VMAT1 and tyrosine hydroxylase, the rate-limiting enzyme for catecholamine biosynthesis, were co-localized in the same glomus cells and a positive correlation was confirmed between the two immunoreactivities (Spearman's coefficient = 0.82; p <  0.05). Although some glomus cells showed co-localization of VMAT2 and dopamine β-hydroxylase immunoreactivity, the biosynthetic enzyme for noradrenaline, VMAT2 immunoreactivity appeared to be less associated with both catecholamine-synthesizing enzymes as indicated by a correlation analysis (TH: Spearman's coefficient = 0.38, DBH: Spearman's coefficient = 0.26). These results indicate that heterogeneity on functional role would exist among glomus cells in terms of VMAT isoform and catecholamine-synthesizing enzymes expression.

中文翻译：

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大鼠颈动脉水泡单胺转运蛋白1和2免疫反应性glomus细胞之间儿茶酚胺合成酶表达的差异。

囊泡单胺转运蛋白（VMAT）1和2负责单胺转运到秘书小泡中，并在包括颈动脉体（CB）在内的中枢和外周单胺能组织中特异性表达。本研究的目的是使用多重免疫标记法检查大鼠CB的VMAT1和VMAT2免疫反应性球蛋白细胞中儿茶酚胺合成酶的表达。通过RT-PCR证实了CB中VMAT1和VMAT2 mRNA的表达。免疫组织化学显示，VMAT1免疫反应性在球蛋白细胞中占主导地位，而不是VMAT2免疫反应性。具有VMAT1免疫反应性的Glomus细胞表现出弱/阴性的VMAT2免疫反应性，反之亦然。VMAT1和酪氨酸羟化酶（儿茶酚胺生物合成的限速酶）的免疫反应性，它们在相同的球状细胞中共定位，并且在两种免疫反应性之间证实了正相关（Spearman系数= 0.82； p <0.05）。尽管一些球蛋白细胞显示VMAT2和多巴胺β-羟化酶免疫反应共定位，但如相关分析所示，去甲肾上腺素，VMAT2免疫反应的生物合成酶似乎与儿茶酚胺合成酶的相关性较低（TH：Spearman系数= 0.38， DBH：Spearman系数= 0.26）。这些结果表明，根据VMAT同工型和儿茶酚胺合成酶的表达，球蛋白细胞之间将存在功能上的异质性。尽管一些球蛋白细胞显示VMAT2和多巴胺β-羟化酶免疫反应共定位，但如相关分析所示，去甲肾上腺素，VMAT2免疫反应的生物合成酶似乎与儿茶酚胺合成酶的相关性较低（TH：Spearman系数= 0.38， DBH：Spearman系数= 0.26）。这些结果表明，根据VMAT同工型和儿茶酚胺合成酶的表达，球蛋白细胞之间将存在功能上的异质性。尽管一些球蛋白细胞显示VMAT2和多巴胺β-羟化酶免疫反应共定位，但如相关分析所示，去甲肾上腺素，VMAT2免疫反应的生物合成酶似乎与儿茶酚胺合成酶的相关性较低（TH：Spearman系数= 0.38， DBH：Spearman系数= 0.26）。这些结果表明，根据VMAT同工型和儿茶酚胺合成酶的表达，球蛋白细胞之间将存在功能上的异质性。DBH：Spearman系数= 0.26）。这些结果表明，根据VMAT同工型和儿茶酚胺合成酶的表达，球蛋白细胞之间将存在功能上的异质性。DBH：Spearman系数= 0.26）。这些结果表明，根据VMAT同工型和儿茶酚胺合成酶的表达，球蛋白细胞之间将存在功能上的异质性。