Enhanced AMPAR-dependent synaptic transmission by S-nitrosylation in the vmPFC contributes to chronic inflammatory pain-induced persistent anxiety in mice

Zhi-jin Chen1, Chun-wan Su1, Shuai Xiong1, Ting Li1, Hai-ying Liang1,2, Yu-hui Lin1, Lei Chang1, Hai-yin Wu1,3, Fei Li4, Dong-ya Zhu1,3, Chun-xia Luo1,3
1 Department of Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China
2 The First Affiliated Hospital of Fujian Medical University, Longyan 364000, China
3 Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou 510515, China
4 Department of Medicinal Chemistry, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China
Correspondence to: Chun-xia Luo:,
DOI: 10.1038/s41401-022-01024-z
Received: 1 August 2022
Accepted: 2 November 2022
Advance online: 2 December 2022


Chronic pain patients often have anxiety disorders, and some of them suffer from anxiety even after analgesic administration. In this study, we investigated the role of AMPAR-mediated synaptic transmission in the ventromedial prefrontal cortex (vmPFC) in chronic pain-induced persistent anxiety in mice and explored potential drug targets. Chronic inflammatory pain was induced in mice by bilateral injection of complete Freund’s adjuvant (CFA) into the planta of the hind paws; anxiety-like behaviours were assessed with behavioural tests; S-nitrosylation and AMPAR-mediated synaptic transmission were examined using biochemical assays and electrophysiological recordings, respectively. We found that CFA induced persistent upregulation of AMPAR membrane expression and function in the vmPFC of anxious mice but not in the vmPFC of non-anxious mice. The anxious mice exhibited higher S-nitrosylation of stargazin (an AMPAR-interacting protein) in the vmPFC. Inhibition of S-nitrosylation by bilaterally infusing an exogenous stargazin (C302S) mutant into the vmPFC rescued the surface expression of GluA1 and AMPAR-mediated synaptic transmission as well as the anxiety-like behaviours in CFA-injected mice, even after ibuprofen treatment. Moreover, administration of ZL006, a small molecular inhibitor disrupting the interaction of nNOS and PSD-95 (20 mg·kg−1·d−1, for 5 days, i.p.), significantly reduced nitric oxide production and S-nitrosylation of AMPAR-interacting proteins in the vmPFC, resulting in anxiolytic-like effects in anxious mice after ibuprofen treatment. We conclude that S-nitrosylation is necessary for AMPAR trafficking and function in the vmPFC under chronic inflammatory pain-induced persistent anxiety conditions, and nNOS-PSD-95 inhibitors could be potential anxiolytics specific for chronic inflammatory pain-induced persistent anxiety after analgesic treatment.
Keywords: chronic pain; anxiety; vmPFC; AMPAR trafficking; S-nitrosylation; stargazin

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