Gonzalo-Ruiz A, Alonso A, Sanz J M, Llinás R R
Department of Anatomy, University College of Soria, Spain.
J Comp Neurol. 1992 Jul 8;321(2):300-11. doi: 10.1002/cne.903210209.
The presence and distribution of dopaminergic neurons and terminals in the hypothalamus of the rat were studied by tyrosine hydroxylase (TH) immunohistochemistry. Strongly labelled TH-immunoreactive neurons were seen in the dorsomedial hypothalamic nucleus, periventricular region, zona incerta, arcuate nucleus, and supramammillary nucleus. A few TH-positive neurons were also identified in the dorsal and ventral premammillary nucleus, as well as the lateral hypothalamic area. TH-immunoreactive fibres and terminals were unevenly distributed in the mammillary nuclei; small, weakly labelled terminals were scattered in the medial mammillary nucleus, while large, strongly labelled, varicose terminals were densely concentrated in the internal part of the lateral mammillary nucleus. A few dorsoventrally oriented TH-positive axon bundles were also identified in the lateral mammillary nucleus. A dopaminergic projection to the mammillary nuclei from the supramammillary nucleus and lateral hypothalamic area was identified by double labelling with retrograde transport of wheat germ agglutinin-horseradish peroxidase and TH-immunohistochemistry. The lateral mammillary nucleus receives a weak dopaminergic projection from the medial, and stronger projections from the lateral, caudal supramammillary nucleus. The double-labelled neurons in the lateral supramammillary nucleus appear to encapsulate the caudal end of the mammillary nuclei. The medial mammillary nucleus receives a very light dopaminergic projection from the caudal lateral hypothalamic area. These results suggest that the supramammillary nucleus is the principal source of the dopaminergic input to the mammillary nuclei, establishing a local TH-pathway in the mammillary complex. The supramammillary cell groups are able to modulate the limbic system through its dopaminergic input to the mammillary nuclei as well as through its extensive dopaminergic projection to the lateral septal nucleus.
采用酪氨酸羟化酶（TH）免疫组织化学方法，研究了大鼠下丘脑多巴胺能神经元和终末的存在及分布情况。在下丘脑背内侧核、室周区、未定带、弓状核和乳头体上核中可见强标记的TH免疫反应性神经元。在背侧和腹侧乳头前核以及下丘脑外侧区也鉴定出少数TH阳性神经元。TH免疫反应性纤维和终末在乳头体核中分布不均；小的、弱标记的终末散在于内侧乳头体核，而大的、强标记的曲张终末密集集中于外侧乳头体核内部。在外侧乳头体核中还鉴定出少数背腹向的TH阳性轴突束。通过小麦胚凝集素 - 辣根过氧化物酶逆行运输与TH免疫组织化学双重标记，确定了从乳头体上核和下丘脑外侧区到乳头体核的多巴胺能投射。外侧乳头体核接受来自内侧的弱多巴胺能投射，以及来自外侧、尾侧乳头体上核的较强投射。外侧乳头体上核中的双标记神经元似乎包裹着乳头体核的尾端。内侧乳头体核接受来自尾侧下丘脑外侧区的非常微弱的多巴胺能投射。这些结果表明，乳头体上核是乳头体核多巴胺能输入的主要来源，在乳头体复合体中建立了一条局部TH通路。乳头体上核细胞群能够通过其对乳头体核的多巴胺能输入以及通过其对外侧隔核的广泛多巴胺能投射来调节边缘系统。
