Localization of the NBMPR-sensitive equilibrative nucleoside transporter, ENT1, in the rat dorsal root ganglion and lumbar spinal cord
Localization of the NBMPR-sensitive equilibrative nucleoside transporter, ENT1, in the rat dorsal root ganglion and lumbar spinal cord
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DOI：
10.1016/j.brainres.2005.08.017
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发表时间：
2005-10-19
期刊：
影响因子：
2.9
通讯作者：
King, AE
中科院分区：
文献类型：
--
作者：
Governo, RJM;Deuchars, J;King, AE
LENT1是一种平衡的核苷转运体，能够实现腺苷等生物活性嘌呤的跨膜双向扩散。在脊髓背角和感觉传入神经元中，腺苷作为一种神经调节剂，具有复杂的促痛和抗伤害性作用。虽然腺苷的摄取和释放机制被认为存在于背角和感觉传入神经元中，但特定核苷转运体亚型如ENT1的表达谱尚未建立。本研究用特异性ENT1抗体(抗rENT1(227-290)或抗hENT1(227-290))免疫印迹分析了ENT1蛋白在成年大鼠背角和背根节(DRG)组织匀浆中的表达。免疫过氧化物酶标记的ENT1抗体在背角产生特异的染色，主要集中在浅层，尤其是明胶质(11层)。免疫荧光双标记显示ENT1呈点状，在某些情况下，与神经元(Neun证实)或神经胶质细胞(CNPase证实)的细胞体密切相关。对11层ENT1表达的电子显微镜分析表明，ENT1存在于突触前和突触后的成分中，尽管也标记了一些其他结构，包括有髓和无髓轴突。在感觉神经节中，ENT1定位于P物质、1b4或NF共表达的各种大小细胞体中的很高比例，尽管ENT1在肽能群体中表达最高。这些数据首次详细描述了ENT1在大鼠背角和感觉神经节中的表达和细胞分布。ENT1表达与腺苷在突触内稳态调节有关的功能意义仍有待确定。(C)2005 Elsevier B.V.保留所有权利。
LENT1 is an equilibrative nucleoside transporter that enables trans-membrane bi-directional diffusion of biologically active purines such as adenosine. in spinal cord dorsal horn and in sensory afferent neurons, adenosine acts as a neuromodulator with complex pro- and anti-nociceptive actions. Although uptake and release mechanisms for adenosine are believed to exist in both the dorsal horn and sensory afferent neurons, the expression profile of specific nucleoside transporter subtypes such as ENT1 is not established. In this study, immunoblot analysis with specific ENT1 antibodies (anti-rENT1(227-290) or anti-hENT1(227-290)) was used to reveal the expression of ENT1 protein in tissue homogenates of either adult rat dorsal horn or dorsal root ganglia (DRG). Immunoperoxidase labeling with ENT1 antibodies produced specific staining in dorsal horn which was concentrated over Superficial laminae, especially the substantia gelatinosa (lamina 11). Immunofluorescence double-labeling revealed a punctate pattern for ENT1 closely associated, in some instances, with cell bodies of either neurons (confirmed with NeuN) or glia (confirmed with CNPase). Electron microscopy analysis of ENT1 expression in lamina 11 indicated its presence within pre- and post-synaptic elements, although a number of other structures, including myelinated and unmyelinated, axons were also labeled. In sensory ganglia, ENT1 was localized to a high proportion of cell bodies of all sizes that co-expressed substance P, 1B4 or NF, although ENT1 was most highly expressed in the peptidergic population. These data provide the first detailed account of the expression and cellular distribution of ENT1 in rat dorsal horn and sensory ganglia. The functional significance of ENT1 expression with regard to the homeostatic regulation of adenosine at synapses remains to be established. (c) 2005 Elsevier B.V. All rights reserved.