Projections from the insular cortex to pain-receptive trigeminal caudal subnucleus (medullary dorsal horn) and other lower brainstem areas in rats
Projections from the insular cortex to pain-receptive trigeminal caudal subnucleus (medullary dorsal horn) and other lower brainstem areas in rats
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DOI：
10.1016/j.neuroscience.2012.12.024
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发表时间：
2013-03
期刊：
影响因子：
3.3
通讯作者：
F. Sato;F. Akhter;T. Haque;T. Kato;R. Takeda;Y. Nagase;B. Sessle;A. Yoshida
中科院分区：
文献类型：
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作者：
F. Sato;F. Akhter;T. Haque;T. Kato;R. Takeda;Y. Nagase;B. Sessle;A. Yoshida
本研究探讨了大鼠岛叶皮层（Ins）向脑干下部可能参与口面疼痛加工的区域的投射。我们首先研究了分布的Ins神经元直接投射到三叉神经尾侧亚核（Vc，延髓背角）和口腔亚核（Vo），这是已知的接受orofacial伤害性输入。将荧光金（FG）逆行注入Vc I/II层的内侧部和外侧部后，在两侧分别出现对侧优势的颗粒Ins（GI）和脱颗粒Ins（DI）的吻侧水平和GI/DI的尾侧水平的标记，而在无颗粒Ins（AI）中无标记。Vc Ⅲ-Ⅴ层注射FG后，无Ins神经元被标记。FG注射到Vo后，许多神经元标记双侧与对侧优势的头侧和尾侧GI/DI，但没有在AI。然后，我们检查了从GI/DI到下脑干的下行投射。将生物素化葡聚糖胺（BDA）顺行示踪剂注入GI/DI头端后，在双侧Vc的I/II层内侧部、背内侧Vo、三叉神经区、延髓头端腹内侧核（RVM）和孤束核中可见许多BDA标记的轴突和终末，在同侧臂旁核（Pb）中也有标记，Köliker-Nerve核（KF）和三叉神经中脑核。在尾侧GI/DI注射BDA后，在双侧Vc、腹外侧Vo、三叉神经前区和RVM的I/II层外侧部可见对侧优势，在中脑导水管周围灰质、Pb和KF的外侧区（PAG 1）可见同侧优势。上述结果提示，GI/DI可能直接或间接地通过脑干核团如PAG 1、Pb、KF和RVM调节Vc和Vo神经元的口面伤害性信息加工。
This study examined the projections from the rat insular cortex (Ins) to lower brainstem areas which are possibly involved in orofacial pain processing. We first examined distributions of Ins neurons projecting directly to the trigeminal caudal subnucleus (Vc, medullary dorsal horn) and oral subnucleus (Vo) which are known to receive orofacial nociceptive inputs. After injections of a retrograde tracer, Fluorogold (FG), into the medial part and lateral part of laminae I/II of Vc, many neurons were labeled bilaterally with a contralateral predominance in the rostral level of granular Ins (GI) and dysgranular Ins (DI) and the caudal level of GI/DI, respectively, but none in the agranular Ins (AI). After FG injections into laminae III–V of Vc, no Ins neurons were labeled. After FG injections into the Vo, many neurons were labeled bilaterally with a contralateral predominance in the rostral and caudal GI/DI, but none in the AI. We then examined descending projections from the GI/DI to the lower brainstem. After injections of an anterograde tracer, biotinylated dextranamine (BDA), into the rostral GI/DI, many BDA-labeled axons and terminals were seen bilaterally with a contralateral predominance in the medial part of laminae I/II of Vc, dorsomedial Vo, juxtatrigeminal region, rostral ventromedial medulla (RVM), and nucleus of the solitary tract, and with an ipsilateral predominance in the parabrachial nucleus (Pb), Kölliker–Fuse nucleus (KF) and trigeminal mesencephalic nucleus. After BDA injections into the caudal GI/DI, they were seen bilaterally with a contralateral predominance in the lateral part of laminae I/II of Vc, ventrolateral Vo, juxtatrigeminal region and RVM, and with an ipsilateral dominance in the lateral zone (PAGl) of periaqueductal gray, Pb and KF. These results suggest that orofacial nociceptive processing of Vc and Vo neurons may be regulated by GI/DI directly or indirectly through brainstem nuclei such as PAGl, Pb, KF and RVM.