Protein Kinase B/Akt Is Required for Complete Freund's Adjuvant-Induced Upregulation of Nav1.7 and Nav1.8 in Primary Sensory Neurons

JOURNAL OF PAIN

卷:14

Article

Liang, Lingli¹  Fan, Longchang^1,2  Tao, Bo³  Yaster, Myron¹  Tao, Yuan-Xiang¹ 

[1] Johns Hopkins Univ, Sch Med, Dept Anesthesiol & Crit Care Med, Baltimore, MD 21205 USA

[2] Huazhong Univ Sci & Technol, Tongji Med Coll, Tongji Hosp, Dept Anesthesiol, Wuhan 430074, Peoples R China

[3] Johns Hopkins Univ, Zanvyl Krieger Sch Arts & Sci, Undergrad Program Publ Hlth Studies, Baltimore, MD 21205 USA

关键词: Nav1.7;    Nav1.8;    Akt;    dorsal root ganglion;    inflammatory pain;   

DOI  :  10.1016/j.jpain.2013.01.778

来源: Elsevier

【 摘 要 】

Voltage-gated sodium channels (Nay) are essential for the generation and conduction of action potentials. Peripheral inflammation increases the expression of Nav1.7 and Nav1.8 in dorsal root ganglion (DRG) neurons, suggesting that they participate in the induction and maintenance of chronic inflammatory pain. However, how Nav1.7 and Nav1.8 are regulated in the DRG under inflammatory pain conditions remains unclear. Using a complete Freund's adjuvant (CFA)-induced chronic inflammatory pain model and Western blot analysis, we found that phosphorylated Akt (p-Akt) was significantly increased in the ipsilateral L4/5 DRGs of rats on days 3 and 7 after intraplantar CFA injection. Immunohistochemistry showed that the percentage of p-Akt-positive neurons in the DRG was also significantly increased in the ipsilateral L4/5 DRGs at these time points. Moreover, CFA injection increased the colocalization of p-Akt with Nav1.7 and Nav1.8 in L4/5 DRG neurons. Pretreatment of rats with an intrathecal injection of Akt inhibitor IV blocked CFA-induced thermal hyperalgesia and CFA-induced increases in Nav1.7 and Nav1.8 in the L4/5 DRGs on day 7 after CFA injection. Our findings suggest that the Akt pathway participates in inflammation-induced upregulation of Nav1.7 and Nav1.8 expression in DRG neurons. This participation might contribute to the maintenance of chronic inflammatory pain. Perspective: This article presents that inhibition of Akt blocks CFA-induced thermal hyperalgesia and CFA-induced increases in dorsal root ganglion Nav1.7 and Nav1.8. These findings have potential implications for use of Akt inhibitors to prevent and/or treat persistent inflammatory pain. (C) 2013 by the American Pain Society

【 授权许可】

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