大鼠中脑导水管周围灰质和中缝背核向臂旁核的5-羟色胺能投射

Serotoninergic projections from periaqueductal gray and dorsal raphe nucleus to parabrachial nucleus in rats

目的 :观察大鼠中脑导水管周围灰质 (PAG)和中缝背核 (DR)内的 5 羟色胺 (5 HT)能神经元是否向臂旁核(PBN)投射 .方法 :荧光金 (FG)逆行追踪结合 5 HT免疫荧光组织化学染色的双标技术 .结果 :将FG注入PBN后 ,在PAG的尾段腹外侧区和DR观察到许多FG逆标神经元 ;5 HT阳性神经元密集地分布于DR ,在PAG尾段的腹外侧区内 ,也能见到一些大型 5 HT阳性神经元 ;PAG尾段腹外侧区和DR的部分FG逆标神经元呈 5 HT阳性 .结论 :PAG和DR内的 5 HT能神经元向PBN发出投射 ,通过作用于PBN内的局部环路神经元或投射神经元 ,可能参与躯体和

AIM: To observe the serotoninergic projections from the periaqueductal gray (PAG) and dorsal raphe nucleus (DR) to the parabrachial nucleus (PBN) in rats. METHODS: Fluoro Gold (FG) retrograde tracing combined with serotonin (5 HT) immunofluorescence histochemical staining method was used. RESULTS: In the rats injected with FG into the PBN, many neurons retrogradely labeled with FG were observed in the ventrolateral subdivision at the caudal level of the PAG and in the DR. 5 HT like immunoreactive neurons were densely localized in the DR. Some 5 HT like immunoreactive neurons were also found in the ventrolateral subdivision at the caudal level of the PAG. A few FG retrogradely labeled neurons also showed 5 HT like immunoreactivities. The majority of the FG/5 HT double labeled neurons distributed in the ventrolateral subdivision at the caudal level of the PAG and in the DR. CONCLUSION: 5 HT released from the PAG and DR neurons which send projection fibers to the PBN may modulate ascending somatic and/or visceral nociceptive information as it is relayed through the PBN to the forebrain sites.