大鼠延髓网状背侧亚核内5-羟色胺能、P物质样和脑啡肽样阳性终末的中枢起源

研究用荧光金（ＦＧ）逆行追踪与免疫荧光组化染色相结合的双标技术对大鼠脑干向延髓网状背侧亚核（ＳＲＤ）的５┐羟色胺（５┐ＨＴ）能、Ｐ物质（ＳＰ）能和亮氨酸┐脑啡肽（Ｌ┐ＥＮＫ）能投射进行了观察。将ＦＧ注入ＳＲＤ后，ＦＧ逆标神经元主要见于中脑导水管周围灰质、脑干中缝核簇（中缝背核、中缝正中核、中缝桥核、中缝大核、中缝隐核和中缝苍白核）、巨细胞网状核α部、延髓网状结构的内侧部和外侧部、延髓外侧网状核、三叉神经脊束核尾侧亚核和孤束核。５┐羟色胺（５┐ＨＴ）样、Ｐ物质（ＳＰ）样和亮氨酸脑啡肽（Ｌ┐ＥＮＫ）样阳性神经元主要见于中脑导水管周围灰质、脑干中缝核簇和巨细胞网状核α部；此外，ＳＰ样和Ｌ┐ＥＮＫ样阳性神经元还见于臂旁核、背外侧被盖核和孤束核。ＦＧ逆标并呈５┐ＨＴ样、ＳＰ样或Ｌ┐ＥＮＫ样阳性的双标神经元也主要见于中脑导水管周围灰质、脑干中缝核簇和巨细胞网状核α部，尤其是位于延髓中缝核团内的双标神经元数量较多。本研究的结果说明ＳＲＤ内的５┐ＨＴ样、ＳＰ样和Ｌ┐ＥＮＫ样阳性终末主要来自中脑导水管周围灰质、脑干中缝核簇和巨细胞网状核α部，向ＳＲＤ发出５┐ＨＴ能、ＳＰ能和Ｌ┐ＥＮＫ能投射的上述核团对ＳＲＤ发挥“弥漫性伤害抑

CENTRAL ORIGINS OF SEROTONIN LIKE, SUBSTANCE P LIKE AND LEUCINE ENKEPHALIN LIKE IMMUNOREACTIVE TERMINALS IN THE SUBNUCLEUS RETICULARIS DORSALIS OF MEDULLA IN THE RAT

A double labeling method by combining Fluro Gold (FG) retrograde tracing with immunofluorescent histochemical staining was used in the present study to observe the serotoninergic, substance P ergic and leucineenkephalinergic projections from the brainstem to the subnucleus reticularis dorsalis (SRD) of medulla in the rat. After injecting FG into the unilateral SRD, FG retrogradely labeled neurons were mainly observed in the midbrain periaqueductal gray (PAG), brainstem raphe nuclei (dorsal raphe nucleus, median raphe nucleus, potine raphe nucleus, nucleus raphe magnus, nucleus raphe obscurus, and nucleus raphe pallidus), reticularis gigantocellularis pars a (Rgca), medial and lateral parts of the medullary reticular formation (MRF), lateral reticularis nucleus (LRt), subnucleus caudalis of the spinal trigeminal nucleus (Vc) and nucleus of the solitay tract (NST). Serotonin (5 HT) , substance P (SP) , and leucine enkephalin (L ENK) like immunoreactive neurons were mainly found in the PAG, brainstem raphe nuclei and Rgca. In addition to those structures, SP and L ENK like immunoreactive neurons were also encounted in the parabrachial nuclei, dorsolateral tegmental nucleus, and NST. Some FG retrogradely labeled neurons showing 5 HT , SP or L ENK like immunoreactivities were mainly observed in the PAG, brainstem raphe nuclei, and Rgca. In the medullary raphe nuclei, the number of double labeled neurons overwhelmed other brainstem structures. The present results indicated that 5 HT , SP or L ENK like immunoreactive terminals in the SRD mainly originated from the PAG, brainstem raphe nuclei, and Rgca, which sent 5 HT , SP or L ENK like immunoreactive terminals to the SRD and might affect the function of SRD in the diffusing noxious inhibitory control.