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Chu Z, Liu P, Li X, Liu Y, Liu F, Lei G, Yang L, Deng L, Dang Y. Microinjection of valproic acid into the ventrolateral orbital cortex exerts an antinociceptive effect in a rat of neuropathic pain. Psychopharmacology (Berl) 2020; 237:2509-2516. [PMID: 32468099 DOI: 10.1007/s00213-020-05551-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 05/11/2020] [Indexed: 12/31/2022]
Abstract
RATIONALE Ventrolateral orbital cortex (VLO) has been found to play an important role in the regulation of neuropathic pain (NPP). As a traditional mood stabilizer, valproic acid (VPA) is currently employed in the treatment of NPP. However, whether VPA plays an analgesic role in VLO is still unknown. OBJECTIVES To elucidate the underlying analgesic mechanism of microinjection of VPA into the VLO on spared nerve injury (SNI), an animal model of NPP. METHODS We firstly examined the role of VPA by intraperitoneal and intral-VLO injection. Then, we accessed its role as a histone deacetylase inhibitor by intral-VLO microinjection of sodium butyrate. Finally, the GABAergic mechanism was measured through the intra-VLO microinjection of several agonists and antagonists of various GABAergic receptor subtypes. RESULTS Both intraperitoneal and intral-VLO injection of VPA attenuated SNI-induced mechanical allodynia. Microinjection of sodium butyrate, one of the histone deacetylase inhibitors, into the VLO attenuated the mechanical allodynia. Besides, microinjection of valpromide, a derivative of VPA which is a GABAergic agonist, into the VLO also attenuated allodynia. Furthermore, microinjection of picrotoxin, a GABAA receptor antagonist, into the VLO attenuated mechanical allodynia; microinjection of picrotoxin before VPA into the VLO increased VPA-induced anti-allodynia. Besides, microinjection of CGP 35348, a GABAB receptor antagonist, into the VLO attenuated allodynia; microinjection of CGP 35348 before VPA into the VLO also increased VPA-induced anti-allodynia. What is more, microinjection of imidazole-4-acetic acid (I4AA), a GABAC receptor antagonist, into the VLO enhanced allodynia; microinjection of I4AA before VPA into the VLO decreased VPA-induced anti-allodynia. CONCLUSIONS These results suggest that both the histone acetylation mechanism and GABAergic system are involved in mediating VLO-induced anti-hypersensitivity.
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Affiliation(s)
- Zheng Chu
- College of Medicine and Forensics, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China
| | - Peng Liu
- Department of Pharmacology and Toxicology, Institute of Basic Medicine Science, Xi'an Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Xin Li
- Zonglian College of Xi'an Jiaotong University, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Yonglong Liu
- Zonglian College of Xi'an Jiaotong University, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Fei Liu
- Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
| | - Gang Lei
- College of Medicine and Forensics, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China
| | - Liu Yang
- College of Medicine and Forensics, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China
| | - Lisha Deng
- College of Medicine and Forensics, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China
| | - Yonghui Dang
- College of Medicine and Forensics, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China. .,Key Laboratory of the Health Ministry for Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China. .,Key Laboratory of Shaanxi Province for Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China. .,State Key Laboratory for Manufacturing Systems Engineering, Xi'an, Shaanxi, People's Republic of China.
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Mohammadi E, Shamsizadeh A, Salari E, Fatemi I, Allahtavakoli M, Roohbakhsh A. Effect of TPMPA (GABACreceptor antagonist) on neuronal response properties in rat barrel cortex. Somatosens Mot Res 2017; 34:108-115. [DOI: 10.1080/08990220.2017.1317240] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Elham Mohammadi
- Physiology–Pharmacology Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
- Department of Physiology and Pharmacology, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Ali Shamsizadeh
- Physiology–Pharmacology Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
- Department of Physiology and Pharmacology, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Elham Salari
- Physiology–Pharmacology Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
- Department of Physiology and Pharmacology, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Iman Fatemi
- Physiology–Pharmacology Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
- Department of Physiology and Pharmacology, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Mohammad Allahtavakoli
- Physiology–Pharmacology Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
- Department of Physiology and Pharmacology, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Ali Roohbakhsh
- Pharmaceutical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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Tadavarty R, Hwang J, Rajput P, Soja P, Kumar U, Sastry B. Are presynaptic GABA-Cρ2 receptors involved in anti-nociception? Neurosci Lett 2015; 606:145-50. [DOI: 10.1016/j.neulet.2015.08.049] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 08/25/2015] [Accepted: 08/26/2015] [Indexed: 11/24/2022]
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Lee KY, Charbonnet M, Gold MS. Upregulation of high-affinity GABA(A) receptors in cultured rat dorsal root ganglion neurons. Neuroscience 2012; 208:133-42. [PMID: 22366297 DOI: 10.1016/j.neuroscience.2012.01.050] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 01/27/2012] [Accepted: 01/31/2012] [Indexed: 10/14/2022]
Abstract
Despite evidence that high-affinity GABA(A) receptor subunit mRNA and protein are present in dorsal root ganglia (DRG), low-affinity currents dominate those detected in acutely dissociated DRG neurons in vitro. This observation raises the possibility that high-affinity receptors are normally trafficked out of the DRG toward central and peripheral terminals. We therefore hypothesized that with time in culture, there would be an increase in high-affinity GABA(A) currents in DRG neurons. To test this hypothesis, we studied dissociated DRG neurons 2 h (acute) and 24 h (cultured) after plating with whole-cell patch-clamp techniques, Western blot, and semiquantitative reverse transcriptase polymerase chain reaction (sqRT-PCR) analysis. GABA(A) current density increases dramatically with time in culture in association with the emergence of two persistent currents with EC50's of 0.25±0.01 μM and 3.2±0.02 μM for GABA activation. In a subpopulation of neurons, there was also an increase in the potency of GABA activation of the transient current from an EC50 of 78.16±10.1 μM to 9.56±1.3 μM with time in culture. A fraction of the high-affinity current was potentiated by δ-subunit agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine-3-ol (THIP). δ-subunit immunoreactivity was largely restricted to the cytosolic fraction in acute, but the membrane fraction in cultured, DRG neurons, with no detectable change in δ-subunit mRNA. However, the emergence of a high-affinity current blocked by THIP and insensitive to bicuculline was detected in a subpopulation of cultured neurons as well in association with an increase in ρ2- and ρ3-subunit mRNA in cultured DRG neurons. Our results suggest that high-affinity δ-subunit-containing GABA(A) receptors are normally trafficked out of the DRG where they are targeted to peripheral and central processes. They also highlight that the interpretation of data obtained from cultured DRG neurons should be made with caution.
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Affiliation(s)
- K Y Lee
- Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA, USA
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Abstract
The inhibitory neurotransmitter, GABA, is a low-molecular-weight molecule that can achieve many low-energy conformations, which are recognized by GABA receptors and transporters. In this article, we assess the structure–activity relationship profiles of GABA analogs at the ionotropic ρ GABAC receptor. Such studies have significantly contributed to the design and development of potent and selective agonists and antagonists for this subclass of GABA receptors. With these tools in hand, the role of ρ GABAC receptors is slowly being realized. Of particular interest is the development of selective phosphinic acid analogs of GABA and their potential use in sleep disorders, inhibiting the development of myopia, and in improving learning and memory.
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Johnston GAR, Chebib M, Hanrahan JR, Mewett KN. Neurochemicals for the investigation of GABA(C) receptors. Neurochem Res 2010; 35:1970-7. [PMID: 20963487 DOI: 10.1007/s11064-010-0271-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2010] [Indexed: 01/23/2023]
Abstract
GABA(C) receptors are being investigated for their role in many aspects of nervous system function including memory, myopia, pain and sleep. There is evidence for functional GABA(C) receptors in many tissues such as retina, hippocampus, spinal cord, superior colliculus, pituitary and the gut. This review describes a variety of neurochemicals that have been shown to be useful in distinguishing GABA(C) receptors from other receptors for the major inhibitory neurotransmitter GABA. Some selective agonists (including (+)-CAMP and 5-methyl-IAA), competitive antagonists (such as TPMPA, (±)-cis-3-ACPBPA and aza-THIP), positive (allopregnanolone) and negative modulators (epipregnanolone, loreclezole) are described. Neurochemicals that may assist in distinguishing between homomeric ρ1 and ρ2 GABA(C) receptors (2-methyl-TACA and cyclothiazide) are also covered. Given their less widespread distribution, lower abundance and relative structural simplicity compared to GABA(A) and GABA(B) receptors, GABA(C) receptors are attractive drug targets.
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Affiliation(s)
- Graham A R Johnston
- Adrien Albert Laboratory of Medicinal Chemistry, Department of Pharmacology D06, The University of Sydney, Sydney, NSW 2006, Australia.
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