Both oral and caudal parts of the spinal trigeminal nucleus project to the somatosensory thalamus in the rat
Both oral and caudal parts of the spinal trigeminal nucleus project to the somatosensory thalamus in the rat
复制标题
DOI：
10.1111/j.1460-9568.2005.03918.x
复制
发表时间：
2005-02-01
影响因子：
3.4
通讯作者：
Voisin, DL
中科院分区：
文献类型：
--
作者：
Guy, N;Chalus, M;Voisin, DL
最近的证据表明，不仅三叉神经脊束核尾侧核(Sp5C)神经元对伤害性刺激有反应，而且三叉神经脊束核口侧核(Sp5O)神经元也有反应。然而，尚不清楚Sp5O神经元是否投射到三叉神经上结构，该结构与口面部伤害性信息的感觉处理有关。本研究采用大鼠荧光金逆行示踪法，观察和比较了Sp5O和Sp5C向丘脑两个主要核团--丘脑腹后内侧核(VPM)和丘脑后核群(Po)--传递上行躯体感觉信息的投射。结果不仅证实了对侧Sp5C向VPM和Po投射的存在，逆行标记神经元在I、III和V板层显示了特定的分布，而且在对侧Sp5O也显示了一致和相似数量的逆行标记细胞体。此外，我们还发现了SP5C和Sp5O的VPM投射的地形图分布：Sp5O和Sp5C背内侧部的神经元投射到VPM内侧，Sp5O和Sp5C腹外侧部的神经元投射到外侧VPM，Sp5O和Sp5C的中间部投射到中间VPM。综上所述，这些数据表明，不仅Sp5C，而且Sp5O也将体感口面部信息从脑干传递到丘脑。此外，三叉神经-VPM通路保存了初级传入神经元在每个亚核的体位分布。这些结果加深了我们对三叉神经体感加工的理解，并有助于指导未来的电生理研究。
Recent evidence has been accumulated that not only spinal trigeminal nucleus caudalis (Sp5C) neurons but also spinal trigeminal nucleus oralis (Sp5O) neurons respond to noxious stimuli. It is unknown, however, whether Sp5O neurons project to supratrigeminal structures implicated in the sensory processing of orofacial nociceptive information. This study used retrograde tracing with Fluorogold in rats to investigate and compare the projections from the Sp5O and Sp5C to two major thalamic nuclei that relay ascending somatosensory information to the primary somatic sensory cortex: the ventroposteromedial thalamic nucleus (VPM) and the posterior thalamic nuclear group (Po). Results not only confirmed the existence of contralateral projections from the Sp5C to the VPM and Po, with retrogradely labelled neurons displaying a specific distribution in laminae I, III and V, they also showed consistent and similar numbers of retrogradely labelled cell bodies in the contralateral Sp5O. In addition, a topographic distribution of VPM projections from Sp5C and Sp5O was found: neurons in the dorsomedial parts of Sp5O and Sp5C projected to the medial VPM, neurons in the ventrolateral Sp5O and Sp5C projected to the lateral VPM, and neurons in intermediate parts of Sp5O and Sp5C projected to the intermediate VPM. All together, these data suggest that not only the Sp5C, but also the Sp5O relay somatosensory orofacial information from the brainstem to the thalamus. Furthermore, trigemino-VPM pathways conserve the somatotopic distribution of primary afferents found in each subnucleus. These results thus improve our understanding of trigeminal somatosensory processing and help to direct future electrophysiological investigations.