大鼠下丘脑内神经激肽B受体阳性神经元向孤束核的直接投射

NEUROKININ B RECEPTOR (NKR) POSITIVE NEURONS IN THE HYPOTHALAMUS PROJECTING TO THE NUCLEUS OF THE SOLITARY TRACT IN THE RAT

为了研究神经激肽Ｂ（ＮＫＢ）可能的升压途径，用免疫荧光组织化学方法结合荧光金（ＦＧ）逆行追踪技术研究了下丘脑内神经激肽Ｂ受体（ＮＫＲ）阳性神经元向孤束核（ＮＴＳ）的投射。ＦＧ微量注射于ＮＴＳ后，ＦＧ逆标细胞主要分布于下丘脑背侧区、室旁核、穹窿周区、外侧区的背侧部和腹外侧部；而ＮＫＲ阳性细胞主要出现于下丘脑的背侧区、室旁核、穹窿周区、外侧区的中段、视上核和乳头体内侧核的内侧亚核。免疫荧光染色结果显示：双标神经元分布在下丘脑背侧区、穹窿周区、外侧区的背侧部和腹外侧部，主要为圆形或椭圆形的中型细胞。双标细胞占ＦＧ标记细胞总数的１１．２％、占ＮＫＲ阳性细胞总数的１１．９％。研究结果显示：下丘脑内部分ＮＫＲ阳性神经元投射至ＮＳＴ，这些投射神经元可能具有调节血压的作用。

Direct projection of the neurons expressing neurokinin B receptor(NKR) from the hypothalamus to the nucleus of the solitary tract(NTS) was carried out in the rat by using fluorescence immunohistochemistry combined with fluorogold(FG) retrograde tracing technique.After injection of FG into the NTS,FG labeled neurons were seen in the dorsal hypothalamic area,paraventricular nucleus,perifornical area,dorsal and ventrolateral parts of the lateral hypothalamic area.On the other hand,NKR positive neurons were mainly observed in the dorsal hypothalamic area,paraventricular nucleus,perifornical area,medial part of the lateral hypothalamic area,supraoptic nucleus and medial part of the medial mammillary nucleus.Immunofluoresent staining showed that FG/NKR double labeled neurons were found in the dorsal hypothalamic area,perifornical area,dorsal and ventrolateral parts of the lateral hypothalamus area.Most of them were medium sized,and round or oval in shape.The doubly labeled neurons constituted 11 2% of the FG labeled neurons and 11 9% of the NKR positive neurons,respectively.The present results revealed that some neurons expressing NKR in the hypothalamus projected to the NTS and suggest that they might be involved in the regulation of blood pressure.