Collateral Projections from the Medullary Dorsal Horn to the Ventral Posteromedial Thalamic Nucleus and the Parafascicular Thalamic Nucleus in the Rat
Collateral Projections from the Medullary Dorsal Horn to the Ventral Posteromedial Thalamic Nucleus and the Parafascicular Thalamic Nucleus in the Rat
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DOI：
10.1016/j.neuroscience.2019.04.050
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发表时间：
2019-07
期刊：
影响因子：
3.3
通讯作者：
Jia-Ni Li;Yi Sun;Songling Ji;Yan-Bing Chen;Jia-Hao Ren;Cheng-Bo He;Zhen-Yu Wu;Hui Li;Yu-Lin Dong;Yun-Qing Li
中科院分区：
文献类型：
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作者：
Jia-Ni Li;Yi Sun;Songling Ji;Yan-Bing Chen;Jia-Hao Ren;Cheng-Bo He;Zhen-Yu Wu;Hui Li;Yu-Lin Dong;Yun-Qing Li
延髓背角（Medullary dorsal horn，MDH）是脊髓背角（spinal dorsal horn）的同源物，在口面区向丘脑腹后内侧核（ventral posteromedial thalamic nucleus，VPM）和丘脑束旁核（parafascicular thalamic nucleus，Pf）等高级中枢传递伤害性信息的过程中起着重要作用。本研究采用逆行双重追踪结合P物质（SP）、SP受体（SPR）和Fos蛋白免疫荧光染色的方法，为MDH神经元是否向VPM和Pf发出侧支投射提供形态学证据。将荧光金（FG）注入VPM，将四甲基罗丹明-葡聚糖（TMR）注入PF，结果表明，FG和TMR双标投射神经元遍布整个MDH，而FG/TMR双标投射神经元主要位于I、III层。在第一板层内，部分FG/TMR双标神经元表达SPR，并与SP免疫阳性终末紧密接触。福尔马林注入口面区后，FG/TMR双标神经元在I层和III层分别有41.4%和34.3%表达Fos蛋白。本研究结果提供了形态学证据表明，在MDH内的一些SPR表达神经元发送侧支投射到VPM和Pf，并可能参与急性口面伤害性信息传递的感觉-辨别和情感方面。
Medullary dorsal horn (MDH), the homolog of spinal dorsal horn, plays essential roles in processing of nociceptive signals from orofacial region toward higher centers, such as the ventral posteromedial thalamic nucleus (VPM) and parafascicular thalamic nucleus (Pf), which belong to the sensory-discriminative and affective aspects of pain transmission systems at the thalamic level, respectively. In the present study, in order to provide morphological evidence for whether neurons in the MDH send collateral projections to the VPM and Pf, a retrograde double tracing method combined with immunofluorescence staining for substance P (SP), SP receptor (SPR) and Fos protein was used. Fluoro-gold (FG) was injected into the VPM and the tetramethylrhodamine-dextran (TMR) was injected into the Pf. The result revealed that both FG- and TMR-labeled projection neurons were observed throughout the entire extent of the MDH, while the FG/TMR double-labeled neurons were mainly located in laminae I and III. It was also found that some of the FG/TMR double-labeled neurons within lamina I expressed SPR and were in close contact with SP-immunoreactive (SP-ir) terminals. After formalin injection into the orofacial region, 41.4% and 34.3% of the FG/TMR double-labeled neurons expressed Fos protein in laminae I and III, respectively. The present results provided morphological evidence for that some SPR-expressing neurons within the MDH send collateral projections to both VPM and Pf and might be involved in sensory-discriminative and affective aspects of acute orofacial nociceptive information transmission.