延髓缝核SP神经元至脊髓背角的下行投射—HRP逆行追踪与免疫细胞化学结合法研究

将HRP分别注入18只大鼠的颈、胸、腰段脊髓背角内,应用HRP逆行追踪与免疫细胞化学结合法,对大鼠延髓缝核至脊髓背角的SP能下行投射进行了观察。至脊髓背角的SP能下行纤维主要来自大缝核(无明显定位关系),其次是隐缝核及苍白缝核。各缝核双标细胞占整个延髓缝核HRP标记细胞总数的百分比分别为:大缝核7.5％,隐缝核2.9％,苍白缝核1.4％。本文还讨论了延髓缝核SP能神经元至脊髓背角下行投射的机能意义。

DESCENDING PROJECTIONS OF SUBSTANCE P-CONTAINING NEURONS OF RAPHE NUCLEI OF THE MEDULLA OBLONGATA TO THE DORSAL HORN OF SPINAL CORD——A STUDY WITH COMBINED METHOD OF HRP RETROGRADE TRACING AND IMMUNOCYTOCHEMISTRY

Descending projections of substance P-containing neurons in the raphe nuclei of medulla oblongata to the dorsal horn of spinal cord were studied by means of combined method of HRP retrograde tracing and immunocytochemistry. 30％ HRP solution was injected into the dorsal horn of cervical, thoracic and lumbar spinal cord in 18 rats. After completing HRP reaction in the Nucleus raphe obscurus (NRO), Nucleus raphe pallidus (NRP) and Nucleus raphe magnus (NRM), the positive sections were selected and stabilized with CoCl_2 for immunocytochemical staining. The results showed that although the descending fibers to the dorsal horn came from all 3 raphe nuclei mentioned above without segmental differences, the main source was the Nucleus raphe magnus. The ratio of double labeled neurons of individual nucleus in total HRP labeled neurons of raphe nuclei of medulla oblongata was as fol lows: NRM 7.5％, NRO 2.9％, NRP 1.4％. The results also suggested that other transmitters might exist in the descending pathway of raphe nuclei of the medulla oblongata to the spinal cord besides substance P.The authors also discussed the possible functional role of this descending pathway in present paper.