大鼠三叉神经脊束核尾侧亚核内向丘脑或臂旁核投射神经元与5-HT样和SP样终末间的联系:激光共聚焦显微镜研究(英文)

用免疫荧光组织化学三重染色技术观察了大鼠三叉神经脊束核尾侧亚核（Vc）浅层（Ⅰ层和Ⅱ层）内向丘脑或臂旁核投射的神经元与下行性5-HT样和初级传入的SP样终末之间的联系。将四甲基罗达明（TMR-DA）注入大鼠丘脑或臂旁核,在Vc的Ⅰ、Ⅱ层内可见TMR－DA逆标神经元,主要位于VcⅠ层。在Vc浅层内还可观察到大量的5－HT样和SP样免疫荧光组织化学染色阳性纤维和终未,5－HT样阳性纤维有较多的膨体。Vc内的这些向丘脑或臂旁核投射的TMR－DA逆标神经元与5－HT样和SP样阳性纤维和终末的分布区基本上重叠。在激光共聚焦显微镜下可以看到5－HT样和SP样阳性终末在Vc浅层内分别围绕TMR－DA逆标神经元的胞体和树突的周围并与之形成密切接触;并且观察到5－HT样和SP样阳性终末同时与TMR－DA逆标神经无形成直接的密切接触。提示Vc浅层向丘脑和臂旁核投射的神经元不仅接受外周初级传入的伤害性信息,还接受下行性5-HT能投射纤维的调控。

THE CONNECTIONS BETWEEN SEROTONIN-, SUBSTANCE P-LIKE IMMUNOREACTIVE TERMINALS AND THALAMIC- OR PARABRACHIAL-PROJECTION NEURONS IN THE CAUDAL SPINAL TRIGEMINAL NUCLEUS OF THE RAT: A CONFOCAL LASER-SCANNING MICROSCOPIC STUDY

A triple immunofluorescence histochemical staining technique was used to examine the connections between serotoninlike immunoreactive (5-HT-LI), substance P(SP)-LI terminals and thalamic(TH)- or para brachial (PBN) - projection neurons in the superficial laminae(lamina Ⅰand lamina Ⅱ) of the caudal spinal trigeminal nucleus(Vc) in the rat with con focal laser-scanning microscopy. 5-HT-LI and SP-LI fibers and terminals were mainly observed in the superficial laminae of the Vc. There were many a-conal varicosities on the 5-HT-LI fibers. In the superficial laminae of the Vc, a substantial number of TH- and PBN-projection neurons were retrogradely labeled with tetramethylrhodamine-dextran amine (TM R- DA ) injected into TH or PBN region.The main distribution areas of 5-HT-LI and SP-LI terminals and TMR-DA labeled neurons were overlapping. Many 5-HT-IJand SP-LI terminals surrounded these TMR-DA labeled neuronal cell bodies and their processes. Confocal laser-scanning microscopy revealed that the vast majority of TMR-DA labeled neuronal cell bodies and dendrites in the superficial laminae of the Vc were found to be in "close apposition" to 5-HT-LI a-conal terminals, as well as SP-LI terminals. The present results suggest that both 5-HT-LI and SP-LI terminals might make direct contacts with single neuronal profiles which project to TH or PBN,and indicate that in the superficial laminae of the Vc, the TH- and PBN-projection neurons receive not only nociceptive information originating from the primary afferents, but also modulation of serotoninergic descending projections.