Schlösser Lukas, Barthel Franziska, Brandenburger Timo, Neumann Elena, Bauer Inge, Eulenburg Volker, Werdehausen Robert, Hermanns Henning
Department of Anesthesiology, Medical Faculty, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany.
Institute of Biochemistry, Emil-Fischer-Center, University of Erlangen-Nürnberg, Fahrstrasse 17, 91054 Erlangen, Germany.
Neurosci Lett. 2015 Jul 23;600:213-9. doi: 10.1016/j.neulet.2015.06.026. Epub 2015 Jun 20.
Glycinergic inhibitory neurotransmission plays a pivotal role in the development of neuropathic pain. The glycine concentration in the synaptic cleft is controlled by the glycine transporters GlyT1 and GlyT2. GlyT1 is expressed throughout the central nervous system, while GlyT2 is exclusively located in glycinergic neurons. Aim of the present study was to investigate whether GlyTs are also expressed in the peripheral sensory nervous system and whether their expression is modulated in experimental neuropathic pain. Neuropathic pain was induced in male Wistar rats by Chronic Constriction Injury (CCI) and verified by assessment of mechanical allodynia (von Frey method). Expression patterns of GlyTs and the glycine binding subunit NR1 of the N-methyl-d-aspartate (NMDA) receptor in the spinal cord and dorsal root ganglia (DRG) were analyzed by Western blot analysis, PCR and immunohistochemistry. While both GlyT1 and GlyT2 were detected in the spinal cord, only GlyT1, but not GlyT2, was detected in DRG. Immunofluorescence revealed a strictly neuronal localization of GlyT1 and a co-localization of GlyT1 and NR1 in DRG. Compared to sham procedure, spinal cord and DRG expression of GlyT1 was not altered and NR1 was unchanged in DRG 12 days after CCI. GlyT1, but not GlyT2, is expressed in the peripheral sensory nervous system. The co-expression of GlyT1 and NMDA receptors in DRG suggests that GlyT1 regulates glycine concentration at the glycine binding site of the NMDA receptor. Differential regulation of GlyT1 expression in the spinal cord or DRG, however, does not seem to be associated with the development of neuropathic pain.
甘氨酸能抑制性神经传递在神经性疼痛的发展中起关键作用。突触间隙中的甘氨酸浓度由甘氨酸转运体GlyT1和GlyT2控制。GlyT1在整个中枢神经系统中表达，而GlyT2仅位于甘氨酸能神经元中。本研究的目的是调查甘氨酸转运体是否也在外周感觉神经系统中表达，以及它们的表达在实验性神经性疼痛中是否受到调节。通过慢性缩窄损伤（CCI）在雄性Wistar大鼠中诱导神经性疼痛，并通过机械性异常性疼痛评估（von Frey法）进行验证。通过蛋白质免疫印迹分析、聚合酶链反应和免疫组织化学分析脊髓和背根神经节（DRG）中甘氨酸转运体和N-甲基-D-天冬氨酸（NMDA）受体的甘氨酸结合亚基NR1的表达模式。虽然在脊髓中同时检测到GlyT1和GlyT2，但在DRG中仅检测到GlyT1，未检测到GlyT2。免疫荧光显示GlyT1严格定位于神经元，并且在DRG中GlyT1与NR1共定位。与假手术相比，CCI后12天，脊髓和DRG中GlyT1的表达未改变，DRG中NR1也未改变。GlyT1而非GlyT2在外周感觉神经系统中表达。DRG中GlyT1与NMDA受体的共表达表明GlyT1调节NMDA受体甘氨酸结合位点处的甘氨酸浓度。然而，脊髓或DRG中GlyT1表达的差异调节似乎与神经性疼痛的发展无关。
