Reduced GABAergic neuronal activity in zona incerta causes neuropathic pain in a rat sciatic nerve chronic constriction injury model
Authors Moon HC, Park YS
Received 26 December 2016
Accepted for publication 7 April 2017
Published 11 May 2017 Volume 2017:10 Pages 1125—1134
Checked for plagiarism Yes
Review by Single-blind
Peer reviewers approved by Dr Colin Mak
Peer reviewer comments 3
Editor who approved publication: Dr E Alfonso Romero-Sandoval
Hyeong Cheol Moon,1 Young Seok Park,1,2
1Department of Medical Neuroscience, 2Department of Neurosurgery, Neurofuture Laboratory, College of Medicine, Chungbuk National University Hospital, Cheongju-si, Chungbuk, Republic of Korea
Purpose: The zona incerta (ZI) is below the ventral tier of the thalamus and has a strong influence selectively in higher-order thalamic relays. Although neuropathic pain has been suggested to result from reduced gamma-aminobutyric acid (GABA) and GABAergic signaling in the ZI, the mechanisms remain unclear. Here, the role of GABA and GABAergic signaling was investigated in the ZI in neuropathic pain using sciatic nerve chronic constriction injury (CCI) rats.
Materials and methods: Single-unit neuronal activity was recorded, and microdialysis was performed in the ZI of CCI rats and sham-treated rats in vivo. This study also compared ZI neuronal activity after treatment with saline, the GABAA receptor agonist (muscimol), or the GABAA receptor antagonist (bicuculline).
Results and conclusion: CCI rats exhibited hypersensitivity to pain as evidenced by decreased hind paw withdrawal threshold and latency. CCI rats also showed reduced GABA level and decreased neuronal activity in the ZI compared with sham-treated rats. Treatment with GABAA receptor agonist, but not GABAA receptor antagonist, ameliorated pain hypersensitivity and increased the firing rate (spikes/s) of ZI neurons in CCI rats.
Keywords: sciatic nerve injury, chronic pain, neuropathic pain, zona incerta, neural cell recording, GABA
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