Yip Siew Hoong, York Jade, Hyland Brian, Bunn Stephen J, Grattan David R
Centre for Neuroendocrinology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
J Chem Neuroanat. 2018 Jul;90:40-48. doi: 10.1016/j.jchemneu.2017.12.002. Epub 2017 Dec 5.
Co-localization of the expression of the dopamine transporter (DAT) with the catecholamine synthesising enzyme tyrosine hydroxylase (TH) has been investigated using transgenic mice expressing Cre recombinase (Cre) dependent green fluorescent protein (GFP) under the control of the DAT promoter (DAT/GFP). Brain sections from adult female mice were stained for Cre-induced GFP and TH using immunohistochemistry, revealing a high degree of co-expression in the midbrain dopaminergic neurons (A8-10) with the exception of the periaqueductal and dorsal raphe nuclei where dual-labelling was notably lower. In contrast, most of the rostral groups of TH-expressing neurons in the forebrain (A11, A13 - A15) showed little or no co-localization with Cre-induced GFP. Interestingly, a subpopulation of about 30% of the TH-immunoreactive neurons in the arcuate nucleus (A12) also express GFP staining. This observation supports the proposal that this hypothalamic cluster of dopaminergic neurons is neurochemically, and thus potentially functionally, heterogeneous. This study extends earlier literature focusing primarily on DAT expression in midbrain structures to demonstrate a heterogeneity of DAT and TH co-localization in forebrain neurons, particularly those in the hypothalamus. It also highlights the importance of carefully selecting and validating transgenic mouse lines when studying dopaminergic neurons.
利用在多巴胺转运体（DAT）启动子（DAT/GFP）控制下表达依赖于Cre重组酶（Cre）的绿色荧光蛋白（GFP）的转基因小鼠，研究了多巴胺转运体（DAT）与儿茶酚胺合成酶酪氨酸羟化酶（TH）表达的共定位情况。对成年雌性小鼠的脑切片进行免疫组织化学染色，检测Cre诱导的GFP和TH，结果显示中脑多巴胺能神经元（A8 - 10）中存在高度共表达，但导水管周围和中缝背核除外，在这些区域双标记明显较低。相比之下，前脑表达TH的神经元的大多数嘴侧组（A11、A13 - A15）与Cre诱导的GFP几乎没有或没有共定位。有趣的是，弓状核（A12）中约30%的TH免疫反应性神经元亚群也表达GFP染色。这一观察结果支持了这样的观点，即下丘脑多巴胺能神经元簇在神经化学上，因此也可能在功能上是异质性的。本研究扩展了早期主要关注中脑结构中DAT表达的文献，以证明前脑神经元，特别是下丘脑中的神经元中DAT和TH共定位的异质性。它还强调了在研究多巴胺能神经元时仔细选择和验证转基因小鼠品系的重要性。
