超极化激活环核苷酸门控阳离子通道亚型在大鼠脊髓背角浅层的特异性表达

目的:探讨超极化激活环核苷酸门控阳离子通道(hyperpolarization-activated cyclic nucleotide-gated cation channels,HCN通道)4种亚型在大鼠脊髓背角浅层的表达与分布特点。方法:选取3~5周龄SD大鼠,雌雄不拘,制作L4~L5段脊髓横切片,应用免疫组织化学技术及激光共聚焦成像技术,观察HCN通道的4种亚型在脊髓背角浅层神经元、胶质细胞及神经元亚细胞结构中的分布。结果:HCN通道不同亚型在正常SD大鼠脊髓背角中的表达和分布具有特异性:(1)HCN1主要与神经元标志物神经元核抗原(neuronal nuclei,NeuN)]和星形胶质细胞标志物胶质细胞原纤维酸性蛋白(glial fibrillary acidic protein,GFAP)]共存,HCN2和HCN3主要与NeuN共定位;(2)HCN2主要与肽能初级传入神经末梢标志物降钙素基因相关肽(calcitonin gene-related peptide,CGRP)]共存,HCN4主要与非肽能初级传入神经末梢标志物异凝集素B4(isolectin B4,IB4)]共存;(3)HCN1和HCN4主要与神经元树突标志物微管相关蛋白2(microtubule-associated protein 2,MAP2)]共存;(4)HCN4主要与抑制性中间神经元轴突末梢标志物囊泡γ-氨基丁酸转运体(vesicularγ-aminobutyric acid transporter,VGAT)]共存。结论:HCN1~4主要分布在大鼠脊髓背角浅层,且在神经元、胶质细胞及神经元亚细胞结构中呈特异性分布。

Specific expression of hyperpolarization-activated cyclic nucleotide-gated cation channel isoforms in rat superficial spinal dorsal horn

AIM:To investigate the distinct expression and localization of the 4 subtypes of hyperpolarizationactivated cyclic nucleotide-gated cation(HCN)channels in rat superficial spinal dorsal horn(SDH).METHODS:Transverse slices of L4~L5 segments were obtained from Sprague-Dawley(SD)rats(3~5-week-old)of either sex. Using the immunohistochemical technique and laser confocal imaging,the distribution of HCN1~4 in neurons,glia cells and subcellular structure of neuron in SDH was observed.RESULTS:The expression of 4 subtypes of HCN channel in rat SDH was distinct:HCN1 was mainly co-localized with neuronal marker neuronal nuclei(NeuN)and astrocyte marker glial fibrillary acidic protein(GFAP). HCN2 and HCN3 were largely co-localized with NeuN. HCN2 was primarily co-localized with peptidergic primary afferent nerve ending marker calcitonin gene-related peptide(CGRP). However,HCN4 was mainly co-localized with non-peptidergic primary afferent nerve ending marker isolectin B4(IB4). HCN1 and HCN4 were mainly co-localized with dendrite marker microtubule-associated protein 2(MAP2). HCN4 was primarily co-localized with axonal terminal of inhibitory interneuron marker vesicular γ-aminobutyric acid transporter(VGAT).CONCLUSION:HCN1~4 are predominantly distributed in superficial spinal dorsal horn and exhibit a specific expression pattern in neurons,glia cells and subcellular structure of neurons.