香草酸受体亚型Ⅰ与降钙素基因相关肽和植物凝集素结合位点在大鼠脊神经节内感觉神经元的共存

Co-localization of vanilloid receptor subtype 1 with calcitonin gene-related peptide and binding isolectin B4 in sensory neurons of the rat dorsal root ganglion

目的:研究香草酸受体亚型Ⅰ(VR1)在大鼠脊神经节(DRG)内感觉神经元的表达,及与降钙素基因相关肽(CGRP)、植物凝集素(IB4)结合位点的共存,为探讨VR1在伤害性感觉刺激信号传导中的作用提供形态学依据。方法:应用免疫荧光组织化学三标方法结合激光共聚焦扫描显微镜技术观察VR1与CGRP和IB4结合位点在DRG的分布及相互关系。结果:背根节内可见大量中、小型神经元胞体和神经纤维表达VR1,一群独特的VR1阳性特小神经元胞体(直径8～11μm)呈荧光强阳性。荧光双标显示背根节内许多VR1阳性神经元与CGRP共存或结合IB4,而CGRP/IB4双标神经元数量稀少。有41.1%±3.2%VR1阳性细胞呈CGRP阳性,有54.9%±3.8%VR1阳性神经元结合IB4。VR1强荧光特小神经元胞体未见CGRP阳性标记或结合IB4。VR1/CGRP/IB4三标神经元数量较少,只有1.5%±1.1%VR1阳性神经元同时呈CGRP阳性并结合IB4。结论:背根节内可能存在VR1/CGRP与VR1/IB4两种不同的与伤害性刺激相关的VR1阳性神经元亚群。

Objective： To study the expression and co-localization of capsaicin receptor, vanilloid receptor subtype Ⅰ （VR1） immunoreactivity with calcitonin gene-related peptide （CGRP） and binding of the isolectin B4 （IB4） in sensory neurons of the rat dorsal root ganglia （DRG） and provide the morphological evidence for exploring the role of VR1 in the signal transduction of nociceptive sensory stimuli. Methods： Triple fluorescent histochemistry combined with laser scanning confocal microscope techniques were used. Results： The extensive expression of VR1 immunoreactivity was found in the neurons and fi bers of the DRG. Most of VR1 immunoreactive neuron cell bodies were middle and small in size. A unique population of very small VR1-immunoreactive neuron cell bodies （diameter 8-11 μm） was intensely fluorescent. Double-labeling showed that numerous VR1 immunoreactive neurons expressed binding IB4, or co-localized with CGRP. CGRP/IB4 double labeling neurons were very few. There were about 41.1 % - 3.2% VR1 immunopositive neurons co-stained with CGRP and 54.9%± 3.8% VR1 immunoreactive neurons showed binding IB4. Very small VR1 immunoreactive intensely fluorescent cell bodies showed neither co staining with CGRP nor binding IB4. VR1/CGRP/IB4 triple labeling neuron cell bodies were rare. Only 1.5% ± 1.1% VR1 immunoreactive neurons co-localized with CGRP and binding IB4. Conclusion： There might be two different VR1 immunoreactive subgroup neurons, VR1/CGRP and VR1/IB4 double-labeling neurons, for noceiception in the DRG of rats.