Differential distribution of Fos-like immunoreactivity in the spinal trigeminal nucleus after noxious and innocuous thermal and chemical stimulation of rat cornea
Differential distribution of Fos-like immunoreactivity in the spinal trigeminal nucleus after noxious and innocuous thermal and chemical stimulation of rat cornea
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DOI：
10.1016/0306-4522(95)00541-2
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发表时间：
1996-05-01
期刊：
影响因子：
3.3
通讯作者：
Bereiter, DA
中科院分区：
文献类型：
--
作者：
Meng, ID;Bereiter, DA
角膜传入神经投射到脊髓三叉核内两个空间上不同的位置：内插亚核/尾侧过渡和尾侧亚核/上颈脊髓过渡。这两个区域在处理角膜输入信号中的作用尚不确定。为了确定这些区域的神经元是否编码应用角膜刺激的不同特征，在巴比妥酸麻醉的大鼠中，对即时早期基因蛋白产物Fos的免疫反应性进行了量化。强度在不同的热刺激（热探针5、35、42、52℃；辐射热类似于45℃）下发生变化，并与使用芥菜油（5 μ l, 20%）或矿物油后的结果进行了比较。与未受刺激的对照组相比，所有刺激均增加了位于内插/尾侧过渡亚核腹外侧极的fos阳性神经元的数量。相比之下，只有52摄氏度的热探针和芥末油在尾核亚核/颈髓过渡的浅纹层内产生了fos阳性神经元的额外峰值。此外，52℃热探针和芥菜油刺激产生的Fos双峰的大小在数量上是不同的。芥末油在内插亚核/尾核过渡处比52℃热探针刺激引起更大的Fos反应，而在尾核亚核（颈髓过渡）处则相反。双标记显示脊髓三叉神经核内Fos免疫反应神经元局限于降钙素基因相关肽密集标记的区域。这些结果表明，与位于尾侧/颈髓过渡区的神经元相比，三叉神经内插-尾侧亚核的神经元对角膜刺激的选择特征（如模态）进行了不同的编码。这两个脑干区域的神经元很可能服务于角膜感觉的不同方面。
Corneal afferent nerves project to two spatially distinct sites within the spinal trigeminal nucleus: the subnucleus interpolaris/caudalis transition and the subnucleus caudalis/upper cervical spinal cord transition. The role of these two regions in processing corneal input is uncertain. To determine if neurons in these regions encode different features of an applied corneal stimulus, immunoreactivity for the immediate early gene protein product, Fos, was quantified in barbiturate-anesthetized rats. Intensity was varied across thermal (thermal probe 5, 35, 42, 52 degrees C; radiant heat of similar to 45 degrees C) stimuli and compared with that seen after mustard oil (5 mu l, 20%) or mineral oil application. Ail stimuli increased the number of Fos-positive neurons located at the ventrolateral pole of the subnucleus interpolaris/caudalis transition compared with unstimulated controls. By contrast, only 52 degrees C thermal probe and mustard oil produced an additional peak of Fos-positive neurons within the superficial laminae at the subnucleus caudalis/cervical cord transition. Further, the magnitudes of the bimodal peaks of Fos produced by 52 degrees C thermal probe and mustard oil stimuli were different quantitatively. Mustard oil caused a greater Fos response at the subnucleus interpolaris/caudalis transition than 52 degrees C thermal probe stimulation, whereas the opposite was true at the subnucleus caudalis(cervical cord transition. Double-labeling revealed that Fos immunoreactive neurons within the spinal trigeminal nucleus were restricted to regions densely labeled for calcitonin gene-related peptide.These results indicate that select features of corneal stimuli such as modality are encoded differently by neurons in the trigeminal subnucleus interpolaris:caudalis transition compared with those located in the subnucleus caudalis/cervical cord transition. It is likely that neurons in these two brainstem regions subserve different aspects of corneal sensation.