Metabotropic glutamate receptor 5 regulates synaptic plasticity in a chronic migraine rat model through the PKC/NR2B sig

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(2020) 21:139

RESEARCH ARTICLE

The Journal of Headache and Pain

Open Access

Metabotropic glutamate receptor 5 regulates synaptic plasticity in a chronic migraine rat model through the PKC/NR2B signal Yingying Niu1, Xiaoxu Zeng1, Lilin Zhao2, Yang Zhou3, Guangcheng Qin1, Dunke Zhang1, Qingqing Fu1, Jiying Zhou4 and Lixue Chen1*

Abstract Background: The mechanism of chronic migraine (CM) is complex, central sensitization is considered as one of the pathological mechanism. Synaptic plasticity is the basis of central sensitization. Metabotropic glutamate receptor 5 (mGluR5) plays a vital role in the synaptic plasticity of the central nervous system. However, whether mGluR5 can promote the central sensitization by regulating synaptic plasticity in CM is unknown. Methods: Male Wistar rats were used to establish a CM rat model, and the expression of mGluR5 mRNA and protein were detected by qRT-PCR and western blot. The allodynia was assessed by mechanical and thermal thresholds, and central sensitization was assessed by expression of the phosphorylation of cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB) at Serine 133(pCREB-S133) and c-Fos. The synaptic-associated protein postsynaptic density protein 95 (PSD), synaptophysin (Syp), and synaptophysin-1(Syt-1), synaptic ultrastructure, and dendritic spines were detected to explore synaptic plasticity. The expression of PKC, total NR2B(tNR2B), and phosphorylation of NR2B at Tyr1472(pNR2B-Y1472) were detected by western blot. Results: We found that the expression of mGluR5 was upregulated in CM rats. Downregulated the mGluR5 with MPEP alleviated the allodynia and reduced the expression of CGRP, pCREB-S133, c-Fos, PSD, Syp and Syt-1 and synaptic transmission. Moreover, the administration of MPEP inhibited the upregulation of PKC and pNR2B-Y1472. Conclusions: These results indicate that mGluR5 contributes to central sensitization by regulating synaptic plasticity in CM through the PKC/NR2B signal, which suggests that mGluR5 may be a potential therapeutic candidate for CM. Keywords: Migraine, Synaptic plasticity, mGluR5, NR2B, PKC

* Correspondence: [email protected] 1 Laboratory Research Center, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds th