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Bai X, Zhang K, Ou C, Nie B, Zhang J, Huang Y, Zhang Y, Huang J, Ouyang H, Cao M, Huang W. Selective activation of AKAP150/TRPV1 in ventrolateral periaqueductal gray GABAergic neurons facilitates conditioned place aversion in male mice. Commun Biol 2023; 6:742. [PMID: 37460788 PMCID: PMC10352381 DOI: 10.1038/s42003-023-05106-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 07/06/2023] [Indexed: 07/20/2023] Open
Abstract
Aversion refers to feelings of strong dislike or avoidance toward particular stimuli or situations. Aversion can be caused by pain stimuli and has a long-term negative impact on physical and mental health. Aversion can also be caused by drug abuse withdrawal, resulting in people with substance use disorder to relapse. However, the mechanisms underlying aversion remain unclear. The ventrolateral periaqueductal gray (vlPAG) is considered to play a key role in aversive behavior. Our study showed that inhibition of vlPAG GABAergic neurons significantly attenuated the conditioned place aversion (CPA) induced by hindpaw pain pinch or naloxone-precipitated morphine withdrawal. However, activating or inhibiting glutamatergic neurons, or activating GABAergic neurons cannot affect or alter CPA response. AKAP150 protein expression and phosphorylated TRPV1 (p-TRPV1) were significantly upregulated in these two CPA models. In AKAP150flox/flox mice and C57/B6J wild-type mice, cell-type-selective inhibition of AKAP150 in GABAergic neurons in the vlPAG attenuated aversion. However, downregulating AKAP150 in glutamatergic neurons did not attenuate aversion. Knockdown of AKAP150 in GABAergic neurons effectively reversed the p-TRPV1 upregulation in these two CPA models utilized in our study. Collectively, inhibition of the AKAP150/p-TRPV1 pathway in GABAergic neurons in the vlPAG may be considered a potential therapeutic target for the CPA response.
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Affiliation(s)
- Xiaohui Bai
- Department of Anesthesiology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
- Department of Anesthesiology, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation. Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Kun Zhang
- Department of Anesthesiology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Chaopeng Ou
- Department of Anesthesiology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Bilin Nie
- Department of Anesthesiology, Guangdong Women and Children Hospital, Guangzhou, China
| | - Jianxing Zhang
- Department of Anesthesiology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Yongtian Huang
- Department of Anesthesiology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Yingjun Zhang
- Department of Anesthesiology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Jingxiu Huang
- Department of Anesthesiology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Handong Ouyang
- Department of Anesthesiology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
| | - Minghui Cao
- Department of Anesthesiology, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation. Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
| | - Wan Huang
- Department of Anesthesiology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
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TRPV1: A Common Denominator Mediating Antinociceptive and Antiemetic Effects of Cannabinoids. Int J Mol Sci 2022; 23:ijms231710016. [PMID: 36077412 PMCID: PMC9456209 DOI: 10.3390/ijms231710016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 12/19/2022] Open
Abstract
The most common medicinal claims for cannabis are relief from chronic pain, stimulation of appetite, and as an antiemetic. However, the mechanisms by which cannabis reduces pain and prevents nausea and vomiting are not fully understood. Among more than 450 constituents in cannabis, the most abundant cannabinoids are Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Cannabinoids either directly or indirectly modulate ion channel function. Transient receptor potential vanilloid 1 (TRPV1) is an ion channel responsible for mediating several modalities of pain, and it is expressed in both the peripheral and the central pain pathways. Activation of TRPV1 in sensory neurons mediates nociception in the ascending pain pathway, while activation of TRPV1 in the central descending pain pathway, which involves the rostral ventral medulla (RVM) and the periaqueductal gray (PAG), mediates antinociception. TRPV1 channels are thought to be implicated in neuropathic/spontaneous pain perception in the setting of impaired descending antinociceptive control. Activation of TRPV1 also can cause the release of calcitonin gene-related peptide (CGRP) and other neuropeptides/neurotransmitters from the peripheral and central nerve terminals, including the vagal nerve terminal innervating the gut that forms central synapses at the nucleus tractus solitarius (NTS). One of the adverse effects of chronic cannabis use is the paradoxical cannabis-induced hyperemesis syndrome (HES), which is becoming more common, perhaps due to the wider availability of cannabis-containing products and the chronic use of products containing higher levels of cannabinoids. Although, the mechanism of HES is unknown, the effective treatment options include hot-water hydrotherapy and the topical application of capsaicin, both activate TRPV1 channels and may involve the vagal-NTS and area postrema (AP) nausea and vomiting pathway. In this review, we will delineate the activation of TRPV1 by cannabinoids and their role in the antinociceptive/nociceptive and antiemetic/emetic effects involving the peripheral, spinal, and supraspinal structures.
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Wang T, Chen Y, Li Y, Wang Z, Qiu C, Yang D, Chen K. TRPV1 Protect against Hyperglycemia and Hyperlipidemia Induced Liver Injury via OPA1 in Diabetes. TOHOKU J EXP MED 2022; 256:131-139. [PMID: 35197406 DOI: 10.1620/tjem.256.131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Type 2 diabetes mellitus (T2DM)-associated mitochondrial impairment may a key factor leading to liver injury. Transient receptor potential receptor vanilloid 1 (TRPV1) regulates the energy expenditure and cholesterol metabolism in hepatocytes and protects against oxidative toxicity. Optic atrophy 1 (OPA1) is involved in the protection of TRPV1 on cardiac microvascular and lung injury. The aim of this study is to identify the role of TRPV1 in redox signals and liver protection via OPA1. TRPV1 knockout (TRPV1-/-) mice were used. And T2DM associated liver injury was induced by high glucose and high fatty acid (HG/HF) treatment. Mechanisms were studied by TUNEL staining, transmission electron microscope (TEM) analysis, reverse transcription polymerase chain reaction (RT-PCR) and Western blotting in vivo and in vitro. We determined that HG/HF treatment increased TRPV1 expression in liver tissues and AML12 cells. The knockout of TRPV1 increased the apoptotic hepatocytes rate. The inhibition of TRPV1 by 5'-iRTX in HG/HF group elevated the reactive oxygen species (ROS) levels, whereas TRPV1 agonist capsaicin reduced ROS. Our studies also showed that the OPA1 expression was lower in livers from HG/HF treated mice than the control, and genetic ablation of TRPV1 decreased OPA1 expression to a greater extent than the HG/HF mice. The protective effects of TRPV1 on mitochondrial were blocked by OPA1 siRNA. In conclusion, our study showed that the identified regulation of TRPV1 to OPA1 has important implication to the pathogenesis of T2DM-associated liver injury. Targeting the action of TRPV1 and OPA1 presents a potential therapeutic intervention.
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Affiliation(s)
- Ting Wang
- Department of Cardiology, The General Hospital of Western Theater Command
| | - Yingmei Chen
- Department of Cardiology, The General Hospital of Western Theater Command
| | - Yong Li
- Department of Cardiology, The People's Hospital of Chaotian District in Guangyuan
| | - Zhen Wang
- Department of Cardiology, The General Hospital of Western Theater Command
| | - Chenming Qiu
- Department of Cardiology, The General Hospital of Western Theater Command
| | - Dachun Yang
- Department of Cardiology, The General Hospital of Western Theater Command
| | - Ken Chen
- Department of Cardiology, Chongqing Renji Hospital, University of Chinese Academy of Sciences.,Department of Cardiology, The Fifth People's Hospital of Chongqing
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Chronic Orofacial Pain: Models, Mechanisms, and Genetic and Related Environmental Influences. Int J Mol Sci 2021; 22:ijms22137112. [PMID: 34281164 PMCID: PMC8268972 DOI: 10.3390/ijms22137112] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 12/13/2022] Open
Abstract
Chronic orofacial pain conditions can be particularly difficult to diagnose and treat because of their complexity and limited understanding of the mechanisms underlying their aetiology and pathogenesis. Furthermore, there is considerable variability between individuals in their susceptibility to risk factors predisposing them to the development and maintenance of chronic pain as well as in their expression of chronic pain features such as allodynia, hyperalgesia and extraterritorial sensory spread. The variability suggests that genetic as well as environmental factors may contribute to the development and maintenance of chronic orofacial pain. This article reviews these features of chronic orofacial pain, and outlines findings from studies in animal models of the behavioural characteristics and underlying mechanisms related to the development and maintenance of chronic orofacial pain and trigeminal neuropathic pain in particular. The review also considers the role of environmental and especially genetic factors in these models, focussing on findings of differences between animal strains in the features and underlying mechanisms of chronic pain. These findings are not only relevant to understanding underlying mechanisms and the variability between patients in the development, expression and maintenance of chronic orofacial pain, but also underscore the importance for considering the strain of the animal to model and explore chronic orofacial pain processes.
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Tang H, Qin S, Li W, Chen X, Ulloa L, Zhu Q, Liu B, Gong Y, Zhao Y, Wang S, Li S, Guo Y, Xu Z, Guo Y. P2RX7 in Dopaminergic Neurons of Ventral Periaqueductal Gray Mediates HTWP Acupuncture-Induced Consciousness in Traumatic Brain Injury. Front Cell Neurosci 2021; 14:598198. [PMID: 33519382 PMCID: PMC7838360 DOI: 10.3389/fncel.2020.598198] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/04/2020] [Indexed: 11/13/2022] Open
Abstract
The induction of a coma by traumatic brain injury (TBI) is a crucial factor for poor clinical prognoses. We report that acupuncture at the hand 12 Jing-Well points (HTWP) improved consciousness and neurologic function in TBI rats. Gene chip analyses showed that HTWP acupuncture mostly activated genes modulating neuronal projections (P2rx7, P2rx3, Trpv1, Tacr1, and Cacna1d), protein secretion (Exoc1, Exoc3l1, Fgb, and Fgr), and dopamine (DA) receptor D3 (Drd3) in the ventral periaqueductal gray (vPAG), among which the expression rate of P2rx7 was the most obviously increased. Acupuncture also increased the expression and excitability of DA and P2RX7 neurons, and the DA neurons expressed P2RX7, P2RX3, and TRPV1 in the vPAG. Intracerebroventricular administration of P2RX7, P2RX3, or TRPV1 antagonists blocked acupuncture-induced consciousness, and the subsequent injection of a P2RX7 antagonist into the vPAG nucleus also inhibited this effect. Our findings provide evidence that acupuncture alleviates TBI-induced comas via DA neurons expressing P2RX7 in the vPAG, so as to reveal the cellular and molecular mechanisms of the improvement of TBI clinical outcomes by HTWP acupuncture.
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Affiliation(s)
- Huiling Tang
- Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Siru Qin
- Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Wei Li
- Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Xuyi Chen
- Department of Neurosurgery, Characteristic Medical Center of Chinese People's Armed Police Force, Tianjin, China.,Institution of Brain Trauma and Neurology Disease of People's Armed Police Forces, Tianjin, China.,Tianjin Key Laboratory of Neurotrauma Repair, Tianjin, China
| | - Luis Ulloa
- Department of Anesthesiology, Center of Perioperative Organ Protection, Duke University Medical Center, Durham, NC, United States
| | - Qiumei Zhu
- Luoding Hospital of Traditional Chinese Medicine, Guangdong, China
| | - Baohu Liu
- Department of Rehabilitation, Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yinan Gong
- Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yadan Zhao
- Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Songtao Wang
- Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Shanshan Li
- Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yongming Guo
- Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Zhifang Xu
- Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yi Guo
- Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,School of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
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The influence of rat strain on the development of neuropathic pain and comorbid anxio-depressive behaviour after nerve injury. Sci Rep 2020; 10:20981. [PMID: 33262364 PMCID: PMC7708988 DOI: 10.1038/s41598-020-77640-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 11/13/2020] [Indexed: 12/16/2022] Open
Abstract
Back-translating the clinical manifestations of human disease burden into animal models is increasingly recognized as an important facet of preclinical drug discovery. We hypothesized that inbred rat strains possessing stress hyper-reactive-, depressive- or anxiety-like phenotypes may possess more translational value than common outbred strains for modeling neuropathic pain. Rats (inbred: LEW, WKY, F344/ICO and F344/DU, outbred: Crl:SD) were exposed to Spared Nerve Injury (SNI) and evaluated routinely for 6 months on behaviours related to pain (von Frey stimulation and CatWalk-gait analysis), anxiety (elevated plus maze, EPM) and depression (sucrose preference test, SPT). Markers of stress reactivity together with spinal/brain opioid receptor expression were also measured. All strains variously developed mechanical allodynia after SNI with the exception of stress-hyporesponsive LEW rats, despite all strains displaying similar functional gait-deficits after injury. However, affective changes reflective of anxiety- and depressive-like behaviour were only observed for F344/DU in the EPM, and for Crl:SD in SPT. Although differences in stress reactivity and opioid receptor expression occurred, overall they were relatively unaffected by SNI. Thus, anxio-depressive behaviours did not develop in all strains after nerve injury, and correlated only modestly with degree of pain sensitivity or with genetic predisposition to stress and/or affective disturbances.
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Exacerbated LPS/GalN-Induced Liver Injury in the Stress-Sensitive Wistar Kyoto Rat Is Associated with Changes in the Endocannabinoid System. Molecules 2020; 25:molecules25173834. [PMID: 32842550 PMCID: PMC7504576 DOI: 10.3390/molecules25173834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/14/2020] [Accepted: 08/20/2020] [Indexed: 02/08/2023] Open
Abstract
Acute liver injury (ALI) is a highly destructive and potentially life-threatening condition, exacerbated by physical and psychological stress. The endocannabinoid system plays a key role in modulating stress and hepatic function. The aim of this study was to examine the development of acute liver injury in the genetically susceptible stress-sensitive Wistar-Kyoto (WKY) rat compared with normo-stress-sensitive Sprague Dawley (SD) rats, and associated changes in the endocannabinoid system. Administration of the hepatotoxin lipopolysaccharide/D-Galactosamine (LPS/GalN) resulted in marked liver injury in WKY, but not SD rats, with increased alanine aminotransferase (ALT), aspartate aminotransferase (AST) and glutamate dehydrogenase (GLDH) plasma levels, significant histopathological changes, increased hepatic pro-inflammatory cytokine expression and caspase-3 activity and expression and reduced Glutathione (GSH) activity. Furthermore, compared to SD controls, WKY rats display increased anandamide and 2-Arachidonoylglycerol levels concurrent with decreased expression of their metabolic enzymes and a decrease in cannabinoid (CB)1 receptor expression following LPS/GalN. CB1 antagonism with AM6545 or CB2 agonism with JWH133 did not alter LPS/GalN-induced liver injury in SD or WKY rats. These findings demonstrate exacerbation of acute liver injury induced by LPS/GalN in a stress-sensitive rat strain, with effects associated with alterations in the hepatic endocannabinoid system. Further studies are required to determine if the endocannabinoid system mediates or modulates the exacerbation of liver injury in this stress-sensitive rat strain.
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Lin J, Song Z, Chen X, Zhao R, Chen J, Chen H, Yang X, Wu Z. Trans-cinnamaldehyde shows anti-depression effect in the forced swimming test and possible involvement of the endocannabinoid system. Biochem Biophys Res Commun 2019; 518:351-356. [PMID: 31421826 DOI: 10.1016/j.bbrc.2019.08.061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 08/10/2019] [Indexed: 01/20/2023]
Abstract
Depression is a mental disease that significantly reduces the quality of patients' life. Around 322 million people of all ages carry the heavy burden of depression on a worldwide scale, with a life-time prevalence of 20% according to the WHO. Trans-cinnamaldehyde (TCA) is an excellent COX-2 inhibitor in central nervous system which is a main constituent of GUIZHI as a member of traditional Chinese herb. Furthermore, previous studies demonstrated that TCA suppressed depression-like behavior in chronic unexpected mild stress, plus maze test and open field test. However, the molecular mechanism of TCA anti-depression effect is not clear. We examined the immobility of TCA pretreated male BALB/c mice in the forced swimming test (FST). Results show that TCA (50 mg/kg, po) revealed a significant effect on reduced immobility in the FST, compared with SAL group which indicated that TCA suppressed depression-like behavior. Moreover, TCA elevated the level of 5-HT and decreased the ratio of Glu/GABA in mice hippocampus. Compared with SAL + FST group, TCA + FST group significantly decreased COX-2, TRPV1 and CB1 protein level in mice hippocampus (p < 0.05, p < 0.05, p < 0.01). These findings suggest that TCA treatment exerted anti-depressive effect and was able to regulate neurotransmitters in the FST. This effect may have positive influence on the endocannabinoid (eCB) system.
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Affiliation(s)
- Jiacheng Lin
- School of Basic Medicine Science, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, China
| | - Zejia Song
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, China
| | - Xiaolei Chen
- School of Basic Medicine Science, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, China
| | - Riji Zhao
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, China
| | - Jiawen Chen
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, China
| | - Huifeng Chen
- School of Nursing, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, China
| | - Xiaodan Yang
- School of Basic Medicine Science, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, China
| | - Zhongping Wu
- School of Basic Medicine Science, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, China.
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Lee YH, Huang YF, Chou HH, Lin WT, Yang HW, Lin-Shiau SY. Studies on a novel regimen for management of orofacial pain and morphine tolerance. J Dent Sci 2018; 13:131-137. [PMID: 30895108 PMCID: PMC6388850 DOI: 10.1016/j.jds.2017.08.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/08/2017] [Indexed: 11/29/2022] Open
Abstract
Background/purpose The prevalence of orofacial pain is high but the etiology of orofacial pain is not well understood. Because of clinical treatment is not so effective, it is urgent to explore novel regimens with more effective and less side effects for clinical application. Materials and methods Male mice (ICR strain) were injected with capsaicin (10μg/5 μl) in vibrissa pad. Spontaneous orofacial pain in 20 min was recorded after receiving capsaicin to quantify the nociceptive level. Green tea polyphenols (GTP 60 mg/kg), memantine (Mem 10 mg/kg), and GTPm (GTP 30 mg/kg plus Mem 3 mg/kg) were dissolved in 2% carboxymethyl cellulose, which was orally administered to mice twice per day and five times per week consecutively for 2 weeks. TruScan photobeam tracking was used to record changes of behavior and locomotor activities. Results GTPm by itself attenuated orofacial pain induced by capsaicin. Moreover, GTPm enhanced morphine analgesic effects, reduced morphine depressant side effects and delayed morphine tolerance. Along with this experiment, GTPm was tested on the hot plate (52 °C)-induced peripheral thermal pain. It was found that both memantine and GTPm reduced morphine-analgesia in hind paw thermal pain. Conclusion In this study, GTP (60 mg/kg/day) orally administrated produced a significant analgesic effect on capsaicin–induced orofacial pain. Memantine combined with GTP synergistically not only reduced orofacial pain but also enhanced morphine analgesic effects. Thus, a new regimen of GTPm orally administered twice per day attenuated orofacial pain after consecutive 5 days.
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Woodhams SG, Chapman V, Finn DP, Hohmann AG, Neugebauer V. The cannabinoid system and pain. Neuropharmacology 2017; 124:105-120. [PMID: 28625720 PMCID: PMC5785108 DOI: 10.1016/j.neuropharm.2017.06.015] [Citation(s) in RCA: 174] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/31/2017] [Accepted: 06/14/2017] [Indexed: 01/20/2023]
Abstract
Chronic pain states are highly prevalent and yet poorly controlled by currently available analgesics, representing an enormous clinical, societal, and economic burden. Existing pain medications have significant limitations and adverse effects including tolerance, dependence, gastrointestinal dysfunction, cognitive impairment, and a narrow therapeutic window, making the search for novel analgesics ever more important. In this article, we review the role of an important endogenous pain control system, the endocannabinoid (EC) system, in the sensory, emotional, and cognitive aspects of pain. Herein, we briefly cover the discovery of the EC system and its role in pain processing pathways, before concentrating on three areas of current major interest in EC pain research; 1. Pharmacological enhancement of endocannabinoid activity (via blockade of EC metabolism or allosteric modulation of CB1receptors); 2. The EC System and stress-induced modulation of pain; and 3. The EC system & medial prefrontal cortex (mPFC) dysfunction in pain states. Whilst we focus predominantly on the preclinical data, we also include extensive discussion of recent clinical failures of endocannabinoid-related therapies, the future potential of these approaches, and important directions for future research on the EC system and pain. This article is part of the Special Issue entitled "A New Dawn in Cannabinoid Neurobiology".
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Affiliation(s)
- Stephen G Woodhams
- Arthritis UK Pain Centre, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom.
| | - Victoria Chapman
- Arthritis UK Pain Centre, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - David P Finn
- Pharmacology & Therapeutics, School of Medicine, Galway Neuroscience Centre and Centre for Pain Research, NCBES, National University of Ireland Galway, University Road, Galway, Ireland
| | - Andrea G Hohmann
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA; Program in Neuroscience, Indiana University, Bloomington, IN, USA; Interdisciplinary Biochemistry Graduate Program, Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA; Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - Volker Neugebauer
- Department of Pharmacology and Neuroscience, Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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Yan S, Kentner AC. Mechanical allodynia corresponds to Oprm1 downregulation within the descending pain network of male and female rats exposed to neonatal immune challenge. Brain Behav Immun 2017; 63:148-159. [PMID: 27742580 DOI: 10.1016/j.bbi.2016.10.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/28/2016] [Accepted: 10/10/2016] [Indexed: 12/31/2022] Open
Abstract
Exposure to painful procedures and/or stressors during the early neonatal period can reprogram the underlying neurocircuitry involved in nociception and neuropathic pain perception. The reprogramming of these systems can result in an enduring elevation in sensitivity towards mechanical and thermal stimuli. Recent evidence suggests that exposure to mild inflammatory mediators during the neonatal period can induce similar pain responses in both adolescent and adult rats. Therefore, we sought to profile changes in the expression of several genes across brain areas involved in the active modulation of nociception and neuropathic pain using a well-recognized model of neonatal inflammation. In the present study male and female Sprague-Dawley rats were administered either the inflammatory endotoxin lipopolysaccharide (LPS; 0.05mg/kg, i.p.) or saline (equivolume) on postnatal days (PND) 3 and 5. During adolescence, hind paw mechanical withdrawal thresholds were evaluated using an electronic von Frey anesthesiometer. Animals challenged neonatally with LPS (nLPS) had increased pain sensitivity on this measure which was associated with decreased Oprm1 expression in the prefrontal cortex (PFC) and periaqueductal gray (PAG) of both male and female rats. Although a 'second hit' with LPS in adolescence (aLPS) did not confer protection or reveal additional vulnerabilities, aLPS given to animals treated neonatally with saline was associated with increased pain sensitivity, but only in females. Interestingly, adolescent inflammatory challenge decreased Hcrt2 mRNA in the PAG and elevated Trpv1 in the PAG and PFC of both sexes. There was no effect of inflammatory treatment on either anxiety or depressive-like behavior suggesting that affective functioning did not account for differences in mechanical pain sensitivity. Finally, a preliminary investigation demonstrated that administration of a broad spectrum antibiotic cocktail attenuated the mechanical sensitivity that followed nLPS. Together, these data extend upon evidence that inflammation imparts long term changes in quality of life and pain responses via interference within the descending pain network. Moreover, they highlight a potential window of opportunity to target the microbiota-gut-brain axis and reverse pain processing disturbances following perinatal inflammation.
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Affiliation(s)
- Siyang Yan
- School of Arts & Sciences, Health Psychology Program, MCPHS University (formerly Massachusetts College of Pharmacy & Health Sciences), Boston, MA 02115, United States
| | - Amanda C Kentner
- School of Arts & Sciences, Health Psychology Program, MCPHS University (formerly Massachusetts College of Pharmacy & Health Sciences), Boston, MA 02115, United States.
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