Key Laboratory of Pain Basic Research and Clinical Therapy, Department of Neurobiology, Medical College of Soochow University, Suzhou, China.
J Neurophysiol. 2012 Dec;108(11):3024-33. doi: 10.1152/jn.01047.2011. Epub 2012 Sep 19.
The tyrosine kinases of Src family play an important role in the central sensitization following peripheral inflammation. However, whether the Src family in the arcuate nucleus (ARC) of mediobasal hypothalamus is involved in central sensitization remains unknown. The aim of this study was to investigate the role and mechanisms of tyrosine kinases of Src family in N-methyl-d-aspartate (NMDA) receptor activity in the ARC following peripheral inflammation. Peripheral inflammation was induced by unilateral injection of complete Freund's adjuvant (CFA) into rat hindpaw. The neuronal activities of the ARC were recorded using electrophysiological field recording from the in vitro mediobasal hypothalamic slices from control and CFA rats. Expression of total and phosphorylated Src and NR2B subunit protein was analyzed by Western blot and immuoprecipitation. Our results showed that CFA injection resulted in an increase in mechanical and thermal sensitivity, which was partially blocked by neonatal monosodium glutamate treatment. CFA injection also enhanced spontaneous firings of ARC neurons, which were reversed by the NMDA receptor NR2B subunit specific antagonist Ro25-6981 and by PP2, an Src family tyrosine kinase inhibitor. In addition, peripheral inflammation enhanced Src phosphorylation and NMDA receptor NR2B subunit phosphorylation without alteration of total NR2B subunit expression in the ARC. Peripheral inflammation also increased the association of NR2B protein with p-Src protein in the ARC. Administration of PP2 blocked the upregulation of NR2B phosphorylation induced by CFA injection. Taken together, our present results suggest that the arcuate Src activation-induced tyrosine phosphorylation of NR2B NMDA subunit may contribute to inflammatory pain.
Src 家族的酪氨酸激酶在周围炎症后的中枢敏化中发挥重要作用。然而，中脑基底部弓状核（ARC）中的 Src 家族是否参与中枢敏化尚不清楚。本研究旨在探讨 Src 家族酪氨酸激酶在周围炎症后 ARC 中 N-甲基-D-天冬氨酸（NMDA）受体活性中的作用和机制。通过向大鼠后爪单侧注射完全弗氏佐剂（CFA）诱导周围炎症。通过从对照和 CFA 大鼠的离体中脑基底部切片进行电生理场记录来记录 ARC 的神经元活动。通过 Western blot 和免疫沉淀分析总 Src 和磷酸化 NR2B 亚基蛋白的表达。我们的结果表明，CFA 注射导致机械和热敏感性增加，这部分被新生鼠单谷氨酸处理阻断。CFA 注射还增强了 ARC 神经元的自发放电，这被 NMDA 受体 NR2B 亚基特异性拮抗剂 Ro25-6981 和 Src 家族酪氨酸激酶抑制剂 PP2 逆转。此外，周围炎症增强了 Src 磷酸化和 NMDA 受体 NR2B 亚基磷酸化，而 ARC 中的总 NR2B 亚基表达没有改变。周围炎症还增加了 ARC 中 NR2B 蛋白与 p-Src 蛋白的结合。给予 PP2 可阻断 CFA 注射引起的 NR2B 磷酸化的上调。总之，我们的研究结果表明，弓状核 Src 激活诱导的 NR2B NMDA 亚基酪氨酸磷酸化可能与炎症性疼痛有关。
