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Hiroki T, Suto T, Ohta J, Saito S, Obata H. Spinal γ-Aminobutyric Acid Interneuron Plasticity Is Involved in the Reduced Analgesic Effects of Morphine on Neuropathic Pain. THE JOURNAL OF PAIN 2022; 23:547-557. [PMID: 34678470 DOI: 10.1016/j.jpain.2021.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/16/2021] [Accepted: 10/05/2021] [Indexed: 12/25/2022]
Abstract
Systemic administration of morphine increases serotonin (5-HT) in the spinal dorsal horn (SDH), which attenuates the analgesic effects of morphine on neuropathic pain through spinal 5-HT3 receptors. We hypothesized that dysfunction of the descending serotonergic system, including the periaqueductal gray (PAG), contributes to attenuate the efficacy of morphine on neuropathic pain through spinal 5-HT3 receptors and GABA neurons. Morphine (100 ng) injected into the PAG produced analgesic effects in normal rats, but not in spinal nerve ligation (SNL) rats. In vivo microdialysis showed that PAG morphine increased the SDH 5-HT concentration in both groups. Intrathecal injection of the 5-HT3 receptor antagonist ondansetron and the GABAA receptor antagonist bicuculline attenuated the analgesic effects of PAG morphine in normal rats, but increased the effects in SNL rats. The increased analgesic effect of PAG morphine induced by bicuculline was reversed by pretreatment with the tropomyosin receptor kinase B (TrkB) antagonist K252a. Activation of spinal 5-HT3 receptors by 2-methyl-5-HT increased the GABA concentration in both groups. Morphine activates GABAergic interneurons in the SDH by activating descending serotonergic neurons. Functional changes in GABAA receptors from inhibitory to facilitatory through the activation of TrkB receptors may contribute to the attenuated efficacy of morphine against neuropathic pain. PERSPECTIVE: Although morphine provides strong analgesia against acute pain, it has limited efficacy against neuropathic pain. This article demonstrates that functional changes in GABAA receptors in the spinal dorsal horn after nerve injury might strongly contribute to the attenuation of opioid-induced analgesia for neuropathic pain.
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Affiliation(s)
- Tadanao Hiroki
- Department of Anesthesiology, Gunma University Graduate School of Medicine, Maebashi, Japan.
| | - Takashi Suto
- Department of Anesthesiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Jo Ohta
- Department of Anesthesiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Shigeru Saito
- Department of Anesthesiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Hideaki Obata
- Department of Anesthesiology, Saitama Medical Center, Saitama Medical University, Kawagoe, Japan
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52
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Hu Z, Mu Y, Huang L, Hu Y, Chen Z, Yang Y, Huang X, Fu Y, Xi Y, Lin S, Tao Q, Xu F, So KF, Ren C. A visual circuit related to the periaqueductal gray area for the antinociceptive effects of bright light treatment. Neuron 2022; 110:1712-1727.e7. [PMID: 35263618 DOI: 10.1016/j.neuron.2022.02.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/23/2022] [Accepted: 02/14/2022] [Indexed: 12/21/2022]
Abstract
Light is a powerful modulator of non-visual functions. Although accumulating evidence suggests an antinociceptive effect of bright light treatment, the precise circuits that mediate the effects of light on nocifensive behaviors remain unclear. Here, we show that bright light treatment suppresses mouse nocifensive behaviors through a visual circuit related to the lateral and ventral lateral parts of the periaqueductal gray area (l/vlPAG). Specifically, a subset of retinal ganglion cells (RGCs) innervates GABAergic neurons in the ventral lateral geniculate nucleus and intergeniculate leaflet (vLGN/IGL), which in turn inhibit GABAergic neurons in the l/vlPAG. The activation of vLGN/IGL-projecting RGCs, activation of l/vlPAG-projecting vLGN/IGL neurons, or inhibition of postsynaptic l/vlPAG neurons is sufficient to suppress nocifensive behaviors. Importantly, we demonstrate that the antinociceptive effects of bright light treatment are dependent on the activation of the retina-vLGN/IGL-l/vlPAG pathway. Together, our results delineate an l/vlPAG-related visual circuit underlying the antinociceptive effects of bright light treatment.
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Affiliation(s)
- Zhengfang Hu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou 510632, China
| | - Yiman Mu
- Psychology Department, School of Medicine, Jinan University, Guangzhou 510632, China
| | - Lu Huang
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou 510632, China
| | - Yuqing Hu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou 510632, China
| | - Zhiqing Chen
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou 510632, China
| | - Yan Yang
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou 510632, China
| | - Xiaodan Huang
- Department of Neurology and Stroke Center, The First Affiliated Hospital of Jinan University, Guangzhou 510632, China
| | - Yunwei Fu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou 510632, China
| | - Yue Xi
- Neuroscience and Neurorehabilitation Institute, University of Health and Rehabilitation Sciences, Qingdao, China
| | - Song Lin
- Physiology Department, School of Medicine, Jinan University, Guangzhou 510632, China
| | - Qian Tao
- Psychology Department, School of Medicine, Jinan University, Guangzhou 510632, China
| | - Fuqiang Xu
- CAS Key Laboratory of Brain Connectome and Manipulation, The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences (CAS), Shenzhen 518055, China
| | - Kwok-Fai So
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou 510632, China; Neuroscience and Neurorehabilitation Institute, University of Health and Rehabilitation Sciences, Qingdao, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China; Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong-Macao Greater Bay Area, Guangzhou 510515, China; Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou 510530, China; Key Laboratory of Brain and Cognitive Science, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Chaoran Ren
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou 510632, China; Department of Neurology and Stroke Center, The First Affiliated Hospital of Jinan University, Guangzhou 510632, China; Neuroscience and Neurorehabilitation Institute, University of Health and Rehabilitation Sciences, Qingdao, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China; Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong-Macao Greater Bay Area, Guangzhou 510515, China; Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou 510530, China.
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53
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Li J, Bai Y, Liang Y, Zhang Y, Zhao Q, Ge J, Li D, Zhu Y, Cai G, Tao H, Wu S, Huang J. Parvalbumin Neurons in Zona Incerta Regulate Itch in Mice. Front Mol Neurosci 2022; 15:843754. [PMID: 35299695 PMCID: PMC8920991 DOI: 10.3389/fnmol.2022.843754] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 02/08/2022] [Indexed: 12/20/2022] Open
Abstract
Pain and itch are intricately entangled at both circuitry and behavioral levels. Emerging evidence indicates that parvalbumin (PV)-expressing neurons in zona incerta (ZI) are critical for promoting nocifensive behaviors. However, the role of these neurons in itch modulation remains elusive. Herein, by combining FOS immunostaining, fiber photometry, and chemogenetic manipulation, we reveal that ZI PV neurons act as an endogenous negative diencephalic modulator for itch processing. Morphological data showed that both histamine and chloroquine stimuli induced FOS expression in ZI PV neurons. The activation of these neurons was further supported by the increased calcium signal upon scratching behavior evoked by acute itch. Behavioral data further indicated that chemogenetic activation of these neurons reduced scratching behaviors related to histaminergic and non-histaminergic acute itch. Similar neural activity and modulatory role of ZI PV neurons were seen in mice with chronic itch induced by atopic dermatitis. Together, our study provides direct evidence for the role of ZI PV neurons in regulating itch, and identifies a potential target for the remedy of chronic itch.
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Affiliation(s)
- Jiaqi Li
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi’an, China
| | - Yang Bai
- Department of Neurosurgery, General Hospital of Northern Theater Command, Shenyang, China
| | - Yi Liang
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi’an, China
| | - Yiwen Zhang
- The Cadet Team 6 of School of Basic Medicine, Fourth Military Medical University, Xi’an, China
| | - Qiuying Zhao
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi’an, China
| | - Junye Ge
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi’an, China
| | - Dangchao Li
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi’an, China
| | - Yuanyuan Zhu
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi’an, China
| | - Guohong Cai
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi’an, China
| | - Huiren Tao
- Department of Spine Surgery, Shenzhen University General Hospital, Shenzhen, China
| | - Shengxi Wu
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi’an, China
| | - Jing Huang
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi’an, China
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54
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Impaired visceral pain-related functions of the midbrain periaqueductal gray in rats with colitis. Brain Res Bull 2022; 182:12-25. [DOI: 10.1016/j.brainresbull.2022.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 01/12/2022] [Accepted: 02/03/2022] [Indexed: 11/18/2022]
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55
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Chen Z, Lin MT, Zhan C, Zhong NS, Mu D, Lai KF, Liu MJ. A descending pathway emanating from the periaqueductal gray mediates the development of cough-like hypersensitivity. iScience 2022; 25:103641. [PMID: 35028531 PMCID: PMC8741493 DOI: 10.1016/j.isci.2021.103641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/11/2021] [Accepted: 12/13/2021] [Indexed: 01/10/2023] Open
Abstract
Chronic cough is a common refractory symptom of various respiratory diseases. However, the neural mechanisms that modulate the cough sensitivity and mediate chronic cough remain elusive. Here, we report that GABAergic neurons in the lateral/ventrolateral periaqueductal gray (l/vlPAG) suppress cough processing via a descending pathway. We found that l/vlPAG neurons are activated by coughing-like behaviors and that tussive agent-evoked coughing-like behaviors are impaired after activation of l/vlPAG neurons. In addition, we showed that l/vlPAG neurons form inhibitory synapses with the nucleus of the solitary tract (NTS) neurons. The synaptic strength of these inhibitory projections is weaker in cough hypersensitivity model mice than in naïve mice. Important, activation of l/vlPAG GABAergic neurons projecting to the NTS decreases coughing-like behaviors. In contrast, suppressing these neurons enhances cough sensitivity. These results support the notion that l/vlPAG GABAergic neurons play important roles in cough hypersensitivity and chronic cough through disinhibition of cough processing at the medullary level. GABAergic neurons in the l/vlPAG inhibit coughing-like behaviors The l/vlPAG sends predominately inhibitory projections to the NTS l/vlPAG GABAergic neurons modulate coughing-like behaviors via descending projections l/vlPAG-NTS projections mediate cough hypersensitivity via disinhibitory mechanisms
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Affiliation(s)
- Zhe Chen
- State Key Laboratory of Respiratory Disease, Guangdong-Hong Kong-Macao Joint Laboratory of Respiratory Infectious Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, 151 Yan Jiang Xi Road, Guangzhou 510120, China.,Laboratory of Cough, Affiliated Kunshan Hospital of Jiangsu University, Suzhou, Jiangsu 215300, China
| | - Ming-Tong Lin
- State Key Laboratory of Respiratory Disease, Guangdong-Hong Kong-Macao Joint Laboratory of Respiratory Infectious Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, 151 Yan Jiang Xi Road, Guangzhou 510120, China
| | - Chen Zhan
- State Key Laboratory of Respiratory Disease, Guangdong-Hong Kong-Macao Joint Laboratory of Respiratory Infectious Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, 151 Yan Jiang Xi Road, Guangzhou 510120, China
| | - Nan-Shan Zhong
- State Key Laboratory of Respiratory Disease, Guangdong-Hong Kong-Macao Joint Laboratory of Respiratory Infectious Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, 151 Yan Jiang Xi Road, Guangzhou 510120, China
| | - Di Mu
- Department of Anesthesiology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, No. 650 Xin Song Jiang Road, Shanghai 201620, China
| | - Ke-Fang Lai
- State Key Laboratory of Respiratory Disease, Guangdong-Hong Kong-Macao Joint Laboratory of Respiratory Infectious Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, 151 Yan Jiang Xi Road, Guangzhou 510120, China
| | - Mingzhe J Liu
- State Key Laboratory of Respiratory Disease, Guangdong-Hong Kong-Macao Joint Laboratory of Respiratory Infectious Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, 151 Yan Jiang Xi Road, Guangzhou 510120, China
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56
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Zhu X, Xu Y, Shen Z, Zhang H, Xiao S, Zhu Y, Wu M, Chen Y, Wu Z, Xu Y, He X, Liu B, Liu J, Du J, Sun J, Fang J, Shao X. Rostral Anterior Cingulate Cortex–Ventrolateral Periaqueductal Gray Circuit Underlies Electroacupuncture to Alleviate Hyperalgesia but Not Anxiety-Like Behaviors in Mice With Spared Nerve Injury. Front Neurosci 2022; 15:757628. [PMID: 35095390 PMCID: PMC8789679 DOI: 10.3389/fnins.2021.757628] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 12/20/2021] [Indexed: 11/16/2022] Open
Abstract
Neuropathic pain is a common cause of chronic pain and is often accompanied by negative emotions, making it complex and difficult to treat. However, the neural circuit mechanisms underlying these symptoms remain unclear. Herein, we present a novel pathway associated with comorbid chronic pain and anxiety. Using chemogenetic methods, we found that activation of glutamatergic projections from the rostral anterior cingulate cortex (rACCGlu) to the ventrolateral periaqueductal gray (vlPAG) induced both hyperalgesia and anxiety-like behaviors in sham mice. Inhibition of the rACCGlu-vlPAG pathway reduced anxiety-like behaviors and hyperalgesia in the spared nerve injury (SNI) mice model; moreover, electroacupuncture (EA) effectively alleviated these symptoms. Investigation of the related mechanisms revealed that the chemogenetic activation of the rACCGlu-vlPAG circuit effectively blocked the analgesic effect of EA in the SNI mice model but did not affect the chronic pain-induced negative emotions. This study revealed a novel pathway, the rACCGlu-vlPAG pathway, that mediates neuropathic pain and pain-induced anxiety.
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57
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Lubejko ST, Graham RD, Livrizzi G, Schaefer R, Banghart MR, Creed MC. The role of endogenous opioid neuropeptides in neurostimulation-driven analgesia. Front Syst Neurosci 2022; 16:1044686. [PMID: 36591324 PMCID: PMC9794630 DOI: 10.3389/fnsys.2022.1044686] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 11/18/2022] [Indexed: 12/15/2022] Open
Abstract
Due to the prevalence of chronic pain worldwide, there is an urgent need to improve pain management strategies. While opioid drugs have long been used to treat chronic pain, their use is severely limited by adverse effects and abuse liability. Neurostimulation techniques have emerged as a promising option for chronic pain that is refractory to other treatments. While different neurostimulation strategies have been applied to many neural structures implicated in pain processing, there is variability in efficacy between patients, underscoring the need to optimize neurostimulation techniques for use in pain management. This optimization requires a deeper understanding of the mechanisms underlying neurostimulation-induced pain relief. Here, we discuss the most commonly used neurostimulation techniques for treating chronic pain. We present evidence that neurostimulation-induced analgesia is in part driven by the release of endogenous opioids and that this endogenous opioid release is a common endpoint between different methods of neurostimulation. Finally, we introduce technological and clinical innovations that are being explored to optimize neurostimulation techniques for the treatment of pain, including multidisciplinary efforts between neuroscience research and clinical treatment that may refine the efficacy of neurostimulation based on its underlying mechanisms.
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Affiliation(s)
- Susan T. Lubejko
- Department of Neurobiology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Robert D. Graham
- Department of Anesthesiology, Pain Center, School of Medicine, Washington University in St. Louis, St. Louis, MO, United States
| | - Giulia Livrizzi
- Department of Neurobiology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Robert Schaefer
- Department of Anesthesiology, Pain Center, School of Medicine, Washington University in St. Louis, St. Louis, MO, United States
| | - Matthew R. Banghart
- Department of Neurobiology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
- *Correspondence: Matthew R. Banghart,
| | - Meaghan C. Creed
- Department of Anesthesiology, Pain Center, School of Medicine, Washington University in St. Louis, St. Louis, MO, United States
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, United States
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO, United States
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, United States
- Meaghan C. Creed,
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58
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Pati D, Kash TL. Tumor necrosis factor-α modulates GABAergic and dopaminergic neurons in the ventrolateral periaqueductal gray of female mice. J Neurophysiol 2021; 126:2119-2129. [PMID: 34817244 PMCID: PMC8715045 DOI: 10.1152/jn.00251.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 11/16/2021] [Accepted: 11/19/2021] [Indexed: 11/22/2022] Open
Abstract
Neuroimmune signaling is increasingly identified as a critical component of various illnesses, including chronic pain, substance use disorder, and depression. However, the underlying neural mechanisms remain unclear. Proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α), may play a role by modulating synaptic function and long-term plasticity. The midbrain structure periaqueductal gray (PAG) plays a well-established role in pain processing, and although TNF-α inhibitors have emerged as a therapeutic strategy for pain-related disorders, the impact of TNF-α on PAG neuronal activity has not been thoroughly characterized. Recent studies have identified subpopulations of ventrolateral PAG (vlPAG) with opposing effects on nociception, with dopamine (DA) neurons driving pain relief in contrast to GABA neurons. Therefore, we used slice physiology to examine the impact of TNF-α on neuronal activity of both these subpopulations. We focused on female mice since the PAG is a sexually dimorphic region and most studies use male subjects, limiting our understanding of mechanistic variations in females. We selectively targeted GABA and DA neurons using transgenic reporter lines. Following exposure to TNF-α, there was an increase in excitability of GABA neurons along with a reduction in glutamatergic synaptic transmission. In DA neurons, TNF-α exposure resulted in a robust decrease in excitability along with a modest reduction in glutamatergic synaptic transmission. Interestingly, TNF-α had no effect on inhibitory transmission onto DA neurons. Collectively, these data suggest that TNF-α differentially affects the function of GABA and DA neurons in female mice and enhances our understanding of how TNF-α-mediated signaling modulates vlPAG function.NEW & NOTEWORTHY This study describes the effects of TNF-α on two distinct subpopulations of neurons in the vlPAG. We show that TNF-α alters both neuronal excitability and glutamatergic synaptic transmission on GABA and dopamine neurons within the vlPAG of female mice. This provides critical new information on the role of TNF-α in the potential modulation of pain, since activation of vlPAG GABA neurons drives nociception, whereas activation of dopamine neurons drives analgesia.
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Affiliation(s)
- Dipanwita Pati
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Thomas L Kash
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
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Endocannabinoid System Attenuates Oxaliplatin-Induced Peripheral Sensory Neuropathy Through the Activation of CB1 Receptors. Neurotox Res 2021; 39:1782-1799. [PMID: 34792764 DOI: 10.1007/s12640-021-00442-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 11/03/2021] [Accepted: 11/05/2021] [Indexed: 10/19/2022]
Abstract
Oxaliplatin-induced neurotoxicity is expressed as a dose-limiting peripheral sensory neuropathy (PSN). Cannabinoid substances have been investigated for the analgesic effect. This study aimed to investigate the role of cannabinoid receptors in oxaliplatin-associated PSN. Swiss male mice received nine oxaliplatin injections (2 mg/kg, i.v.). Mechanical and thermal nociceptive tests were performed for 56 days. CB1, CB2, and c-Fos expression were assessed in dorsal root ganglia (DRG), spinal cord (SC), trigeminal ganglia (TG), spinal trigeminal nucleus caudalis (Sp5C), and periaqueductal gray (PAG). Iba-1 expression was assessed in DRG and ATF3 in TG. Cannabidiol (10 mg/kg, p.o.) or a CB1/CB2 non-selective agonist (WIN 55,212-2; 0.5 mg/kg, s.c.) or AM251 (CB1 antagonist) or AM630 (CB2 antagonist) (3 mg/kg, i.p.) were injected before oxaliplatin. Oxaliplatin increased CB1 in DRG, SC, TG, Sp5C, and ventrolateral PAG, with no interference in CB2 expression. Cannabidiol increased CB1 in DRG, reduced mechanical hyperalgesia and c-Fos expression in DRG and SC. Additionally, WIN 55,212-2 increased CB1 in DRG, reduced mechanical hyperalgesia, cold allodynia and c-Fos expression in DRG and SC. CB1 blockage hastened the cold allodynia response, but the CB2 antagonist failed to modulate the oxaliplatin-induced nociceptive behavior. Oxaliplatin also increased Iba-1 in DRG, suggesting immune response modulation which was reduced by cannabidiol and enhanced by AM630. The modulation of the endocannabinoid system, through the CB1 receptor, attenuates the oxaliplatin-associated PNS. The activation of the endocannabinoid system could be considered as a therapeutic target for controlling oxaliplatin-associated neuropathy.
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Mercer Lindsay N, Chen C, Gilam G, Mackey S, Scherrer G. Brain circuits for pain and its treatment. Sci Transl Med 2021; 13:eabj7360. [PMID: 34757810 DOI: 10.1126/scitranslmed.abj7360] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Nicole Mercer Lindsay
- Department of Cell Biology and Physiology, UNC Neuroscience Center, Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Biology, CNC Program, Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Chong Chen
- Department of Cell Biology and Physiology, UNC Neuroscience Center, Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Gadi Gilam
- Division of Pain Medicine, Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Sean Mackey
- Division of Pain Medicine, Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Grégory Scherrer
- Department of Cell Biology and Physiology, UNC Neuroscience Center, Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,New York Stem Cell Foundation-Robertson Investigator, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Lyubashina OA, Sivachenko IB, Busygina II. Amygdalofugal Modulation of Visceral Nociceptive Transmission in the Rat Caudal Ventrolateral Medulla under Normal Conditions and Intestinal Inflammation. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021050161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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62
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Mu D, Sun YG. Circuit Mechanisms of Itch in the Brain. J Invest Dermatol 2021; 142:23-30. [PMID: 34662562 DOI: 10.1016/j.jid.2021.09.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/21/2021] [Accepted: 09/21/2021] [Indexed: 12/12/2022]
Abstract
Itch is an unpleasant somatic sensation with the desire to scratch, and it consists of sensory, affective, and motivational components. Acute itch serves as a critical protective mechanism because an itch-evoked scratching response will help to remove harmful substances invading the skin. Recently, exciting progress has been made in deciphering the mechanisms of itch at both the peripheral nervous system and the CNS levels. Key neuronal subtypes and circuits have been revealed for ascending transmission and the descending modulation of itch. In this review, we mainly summarize the current understanding of the central circuit mechanisms of itch in the brain.
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Affiliation(s)
- Di Mu
- Department of Anesthesiology, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yan-Gang Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology (CEBSIT), Chinese Academy of Sciences, Shanghai, China; Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China.
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63
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Dou B, Li Y, Ma J, Xu Z, Fan W, Tian L, Chen Z, Li N, Gong Y, Lyu Z, Fang Y, Liu Y, Xu Y, Wang S, Chen B, Guo Y, Guo Y, Lin X. Role of Neuroimmune Crosstalk in Mediating the Anti-inflammatory and Analgesic Effects of Acupuncture on Inflammatory Pain. Front Neurosci 2021; 15:695670. [PMID: 34408622 PMCID: PMC8366064 DOI: 10.3389/fnins.2021.695670] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 07/05/2021] [Indexed: 12/17/2022] Open
Abstract
Inflammatory pain is caused by peripheral tissue injury and inflammation. Inflammation leads to peripheral sensitization, which may further cause central sensitization, resulting in chronic pain and progressive functional disability. Neuroimmune crosstalk plays an essential role in the development and maintenance of inflammatory pain. Studies in recent years have shown that acupuncture can exert anti-inflammatory and analgesic effects by regulating peripheral (i.e., involving local acupoints and inflamed regions) and central neuroimmune interactions. At the local acupoints, acupuncture can activate the TRPV1 and TRPV2 channels of mast cells, thereby promoting degranulation and the release of histamine, adenosine, and other immune mediators, which interact with receptors on nerve endings and initiate neuroimmune regulation. At sites of inflammation, acupuncture enables the recruitment of immune cells, causing the release of opioid peptides, while also exerting direct analgesic effects via nerve endings. Furthermore, acupuncture promotes the balance of immune cells and regulates the release of inflammatory factors, thereby reducing the stimulation of nociceptive receptors in peripheral organs. Acupuncture also alleviates peripheral neurogenic inflammation by inhibiting the release of substance P (SP) and calcitonin gene-related peptide from the dorsal root ganglia. At the central nervous system level, acupuncture inhibits the crosstalk between glial cells and neurons by inhibiting the p38 MAPK, ERK, and JNK signaling pathways and regulating the release of inflammatory mediators. It also reduces the excitability of the pain pathway by reducing the release of excitatory neurotransmitters and promoting the release of inhibitory neurotransmitters from neurons and glial cells. In conclusion, the regulation of neuroimmune crosstalk at the peripheral and central levels mediates the anti-inflammatory and analgesic effects of acupuncture on inflammatory pain in an integrated manner. These findings provide novel insights enabling the clinical application of acupuncture in the treatment of inflammatory diseases.
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Affiliation(s)
- Baomin Dou
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yanan Li
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Jie Ma
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Zhifang Xu
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China.,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Wen Fan
- Department of Rehabilitation Physical Therapy Course, Faculty of Health Science, Suzuka University of Medical Science, Suzuka, Japan
| | - Lixin Tian
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Zhihan Chen
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Ningcen Li
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yinan Gong
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Zhongxi Lyu
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China.,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yuxin Fang
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China.,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yangyang Liu
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China.,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yuan Xu
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China.,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Shenjun Wang
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China.,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Bo Chen
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China.,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yongming Guo
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China.,School of Acupuncture & Moxibustion and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yi Guo
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China.,School of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Xiaowei Lin
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China.,National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China.,School of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
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64
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Tavares I, Costa-Pereira JT, Martins I. Monoaminergic and Opioidergic Modulation of Brainstem Circuits: New Insights Into the Clinical Challenges of Pain Treatment? FRONTIERS IN PAIN RESEARCH 2021; 2:696515. [PMID: 35295506 PMCID: PMC8915776 DOI: 10.3389/fpain.2021.696515] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/08/2021] [Indexed: 12/22/2022] Open
Abstract
The treatment of neuropathic pain remains a clinical challenge. Analgesic drugs and antidepressants are frequently ineffective, and opioids may induce side effects, including hyperalgesia. Recent results on brainstem pain modulatory circuits may explain those clinical challenges. The dual action of noradrenergic (NA) modulation was demonstrated in animal models of neuropathic pain. Besides the well-established antinociception due to spinal effects, the NA system may induce pronociception by directly acting on brainstem pain modulatory circuits, namely, at the locus coeruleus (LC) and medullary dorsal reticular nucleus (DRt). The serotoninergic system also has a dual action depending on the targeted spinal receptor, with an exacerbated activity of the excitatory 5-hydroxytryptamine 3 (5-HT3) receptors in neuropathic pain models. Opioids are involved in the modulation of descending modulatory circuits. During neuropathic pain, the opioidergic modulation of brainstem pain control areas is altered, with the release of enhanced local opioids along with reduced expression and desensitization of μ-opioid receptors (MOR). In the DRt, the installation of neuropathic pain increases the levels of enkephalins (ENKs) and induces desensitization of MOR, which may enhance descending facilitation (DF) from the DRt and impact the efficacy of exogenous opioids. On the whole, the data discussed in this review indicate the high plasticity of brainstem pain control circuits involving monoaminergic and opioidergic control. The data from studies of these neurochemical systems in neuropathic models indicate the importance of designing drugs that target multiple neurochemical systems, namely, maximizing the antinociceptive effects of antidepressants that inhibit the reuptake of serotonin and noradrenaline and preventing desensitization and tolerance of MOR at the brainstem.
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Affiliation(s)
- Isaura Tavares
- Unit of Experimental Biology, Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal
- Institute of Molecular and Cell Biology, University of Porto, Porto, Portugal
- Institute of Investigation and Innovation in Health, University of Porto, Porto, Portugal
- *Correspondence: Isaura Tavares
| | - José Tiago Costa-Pereira
- Unit of Experimental Biology, Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal
- Institute of Molecular and Cell Biology, University of Porto, Porto, Portugal
- Institute of Investigation and Innovation in Health, University of Porto, Porto, Portugal
- Faculty of Nutrition and Food Science, University of Porto, Porto, Portugal
| | - Isabel Martins
- Unit of Experimental Biology, Department of Biomedicine, Faculty of Medicine, University of Porto, Porto, Portugal
- Institute of Molecular and Cell Biology, University of Porto, Porto, Portugal
- Institute of Investigation and Innovation in Health, University of Porto, Porto, Portugal
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65
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Siemian JN, Arenivar MA, Sarsfield S, Borja CB, Erbaugh LJ, Eagle AL, Robison AJ, Leinninger G, Aponte Y. An excitatory lateral hypothalamic circuit orchestrating pain behaviors in mice. eLife 2021; 10:e66446. [PMID: 34042586 PMCID: PMC8159376 DOI: 10.7554/elife.66446] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 05/12/2021] [Indexed: 11/13/2022] Open
Abstract
Understanding how neuronal circuits control nociceptive processing will advance the search for novel analgesics. We use functional imaging to demonstrate that lateral hypothalamic parvalbumin-positive (LHPV) glutamatergic neurons respond to acute thermal stimuli and a persistent inflammatory irritant. Moreover, their chemogenetic modulation alters both pain-related behavioral adaptations and the unpleasantness of a noxious stimulus. In two models of persistent pain, optogenetic activation of LHPV neurons or their ventrolateral periaqueductal gray area (vlPAG) axonal projections attenuates nociception, and neuroanatomical tracing reveals that LHPV neurons preferentially target glutamatergic over GABAergic neurons in the vlPAG. By contrast, LHPV projections to the lateral habenula regulate aversion but not nociception. Finally, we find that LHPV activation evokes additive to synergistic antinociceptive interactions with morphine and restores morphine antinociception following the development of morphine tolerance. Our findings identify LHPV neurons as a lateral hypothalamic cell type involved in nociception and demonstrate their potential as a target for analgesia.
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Affiliation(s)
- Justin N Siemian
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of HealthBaltimoreUnited States
| | - Miguel A Arenivar
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of HealthBaltimoreUnited States
| | - Sarah Sarsfield
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of HealthBaltimoreUnited States
| | - Cara B Borja
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of HealthBaltimoreUnited States
| | - Lydia J Erbaugh
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of HealthBaltimoreUnited States
| | - Andrew L Eagle
- Department of Physiology, Michigan State UniversityEast LansingUnited States
| | - Alfred J Robison
- Department of Physiology, Michigan State UniversityEast LansingUnited States
| | - Gina Leinninger
- Department of Physiology, Michigan State UniversityEast LansingUnited States
- Institute for Integrative Toxicology at Michigan State UniversityEast LansingUnited States
| | - Yeka Aponte
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of HealthBaltimoreUnited States
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
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66
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Samineni VK, Grajales-Reyes JG, Grajales-Reyes GE, Tycksen E, Copits BA, Pedersen C, Ankudey ES, Sackey JN, Sewell SB, Bruchas MR, Gereau RW. Cellular, circuit and transcriptional framework for modulation of itch in the central amygdala. eLife 2021; 10:e68130. [PMID: 34032210 PMCID: PMC8172243 DOI: 10.7554/elife.68130] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/24/2021] [Indexed: 01/06/2023] Open
Abstract
Itch is an unpleasant sensation that elicits robust scratching and aversive experience. However, the identity of the cells and neural circuits that organize this information remains elusive. Here, we show the necessity and sufficiency of chloroquine-activated neurons in the central amygdala (CeA) for both itch sensation and associated aversion. Further, we show that chloroquine-activated CeA neurons play important roles in itch-related comorbidities, including anxiety-like behaviors, but not in some aversive and appetitive behaviors previously ascribed to CeA neurons. RNA-sequencing of chloroquine-activated CeA neurons identified several differentially expressed genes as well as potential key signaling pathways in regulating pruritis. Finally, viral tracing experiments demonstrate that these neurons send projections to the ventral periaqueductal gray that are critical in modulation of itch. These findings reveal a cellular and circuit signature of CeA neurons orchestrating behavioral and affective responses to pruritus in mice.
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Affiliation(s)
- Vijay K Samineni
- Washington University Pain Center and Department of Anesthesiology, Washington University School of MedicineSt. LouisUnited States
| | - Jose G Grajales-Reyes
- Washington University Pain Center and Department of Anesthesiology, Washington University School of MedicineSt. LouisUnited States
- Medical Scientist Training Program, Washington University School of MedicineSt. LouisUnited States
- Neuroscience Program, Washington University School of MedicineSt. LouisUnited States
| | - Gary E Grajales-Reyes
- Department of Pathology & Immunology, Washington University School of MedicineSt. LouisUnited States
| | - Eric Tycksen
- Genome Technology Access Center, Washington University School of MedicineSeattleUnited States
| | - Bryan A Copits
- Washington University Pain Center and Department of Anesthesiology, Washington University School of MedicineSt. LouisUnited States
| | - Christian Pedersen
- Department of Biomedical Engineering, University of WashingtonSeattleUnited States
| | - Edem S Ankudey
- Washington University Pain Center and Department of Anesthesiology, Washington University School of MedicineSt. LouisUnited States
| | - Julian N Sackey
- Washington University Pain Center and Department of Anesthesiology, Washington University School of MedicineSt. LouisUnited States
| | - Sienna B Sewell
- Washington University Pain Center and Department of Anesthesiology, Washington University School of MedicineSt. LouisUnited States
| | - Michael R Bruchas
- Washington University Pain Center and Department of Anesthesiology, Washington University School of MedicineSt. LouisUnited States
- Departments of Anesthesiology and Pharmacology, University of WashingtonSeattleUnited States
- Departmentsof Neuroscience and Biomedical Engineering, Washington University School of MedicineSt.LouisUnited States
| | - Robert W Gereau
- Washington University Pain Center and Department of Anesthesiology, Washington University School of MedicineSt. LouisUnited States
- Department of Biomedical Engineering, University of WashingtonSeattleUnited States
- Departmentsof Neuroscience and Biomedical Engineering, Washington University School of MedicineSt.LouisUnited States
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67
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Projections from the lateral parabrachial nucleus to the lateral and ventral lateral periaqueductal gray subregions mediate the itching sensation. Pain 2021; 162:1848-1863. [PMID: 33449512 DOI: 10.1097/j.pain.0000000000002193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/30/2020] [Indexed: 11/25/2022]
Abstract
ABSTRACT Lateral and ventral lateral subregions of the periaqueductal gray (l/vlPAG) have been proved to be pivotal components in descending circuitry of itch processing, and their effects are related to the subclassification of neurons that were meditated. In this study, lateral parabrachial nucleus (LPB), one of the most crucial relay stations in the ascending pathway, was taken as the input nucleus to examine the modulatory effect of l/vlPAG neurons that received LPB projections. Anatomical tracing, chemogenetic, optogenetic, and local pharmacological approaches were used to investigate the participation of the LPB-l/vlPAG pathway in itch and pain sensation in mice. First, morphological evidence for projections from vesicular glutamate transporter-2-containing neurons in the LPB to l/vlPAG involved in itch transmission has been provided. Furthermore, chemogenetic and optogenetic activation of the LPB-l/vlPAG pathway resulted in both antipruritic effect and analgesic effect, whereas pharmacogenetic inhibition strengthened nociceptive perception without affecting spontaneous scratching behavior. Finally, in vivo pharmacology was combined with optogenetics which revealed that AMPA receptor-expressing neurons in l/vlPAG might play a more essential role in pathway modulation. These findings provide a novel insight about the connections between 2 prominent transmit nuclei, LPB and l/vlPAG, in both pruriceptive and nociceptive sensations and deepen the understanding of l/vlPAG modulatory roles in itch sensation by chosen LPB as source of ascending efferent projections.
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68
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Gan Z, Li H, Naser PV, Oswald MJ, Kuner R. Suppression of neuropathic pain and comorbidities by recurrent cycles of repetitive transcranial direct current motor cortex stimulation in mice. Sci Rep 2021; 11:9735. [PMID: 33958647 PMCID: PMC8102487 DOI: 10.1038/s41598-021-89122-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/12/2021] [Indexed: 11/16/2022] Open
Abstract
Transcranial, minimally-invasive stimulation of the primary motor cortex (M1) has recently emerged to show promise in treating clinically refractory neuropathic pain. However, there is a major need for improving efficacy, reducing variability and understanding mechanisms. Rodent models hold promise in helping to overcome these obstacles. However, there still remains a major divide between clinical and preclinical studies with respect to stimulation programs, analysis of pain as a multidimensional sensory-affective-motivational state and lack of focus on chronic phases of established pain. Here, we employed direct transcranial M1 stimulation (M1 tDCS) either as a single 5-day block or recurring blocks of repetitive stimulation over early or chronic phases of peripherally-induced neuropathic pain in mice. We report that repeated blocks of stimulation reverse established neuropathic mechanical allodynia more strongly than a single 5-day regime and also suppress cold allodynia, aversive behavior and anxiety without adversely affecting motor function over a long period. Activity mapping revealed highly selective alterations in the posterior insula, periaqueductal gray subdivisions and superficial spinal laminae in reversal of mechanical allodynia. Our preclinical data reveal multimodal analgesia and improvement in quality of life by multiple blocks of M1 tDCS and uncover underlying brain networks, thus helping promote clinical translation.
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Affiliation(s)
- Zheng Gan
- Institute of Pharmacology, Medical Faculty Heidelberg, Heidelberg University, Im Neuenheimer Feld 366, 69120, Heidelberg, Germany
| | - Han Li
- Institute of Pharmacology, Medical Faculty Heidelberg, Heidelberg University, Im Neuenheimer Feld 366, 69120, Heidelberg, Germany
| | - Paul Vincent Naser
- Institute of Pharmacology, Medical Faculty Heidelberg, Heidelberg University, Im Neuenheimer Feld 366, 69120, Heidelberg, Germany
| | - Manfred Josef Oswald
- Institute of Pharmacology, Medical Faculty Heidelberg, Heidelberg University, Im Neuenheimer Feld 366, 69120, Heidelberg, Germany
| | - Rohini Kuner
- Institute of Pharmacology, Medical Faculty Heidelberg, Heidelberg University, Im Neuenheimer Feld 366, 69120, Heidelberg, Germany.
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69
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Khan F, Mehan A. Addressing opioid tolerance and opioid-induced hypersensitivity: Recent developments and future therapeutic strategies. Pharmacol Res Perspect 2021; 9:e00789. [PMID: 34096178 PMCID: PMC8181203 DOI: 10.1002/prp2.789] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/07/2021] [Indexed: 01/07/2023] Open
Abstract
Opioids are a commonly prescribed and efficacious medication for the treatment of chronic pain but major side effects such as addiction, respiratory depression, analgesic tolerance, and paradoxical pain hypersensitivity make them inadequate and unsafe for patients requiring long-term pain management. This review summarizes recent advances in our understanding of the outcomes of chronic opioid administration to lay the foundation for the development of novel pharmacological strategies that attenuate opioid tolerance and hypersensitivity; the two main physiological mechanisms underlying the inadequacies of current therapeutic strategies. We also explore mechanistic similarities between the development of neuropathic pain states, opioid tolerance, and hypersensitivity which may explain opioids' lack of efficacy in certain patients. The findings challenge the current direction of analgesic research in developing non-opioid alternatives and we suggest that improving opioids, rather than replacing them, will be a fruitful avenue for future research.
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Affiliation(s)
- Faris Khan
- School of Clinical MedicineUniversity of CambridgeCambridgeUK
| | - Aman Mehan
- School of Clinical MedicineUniversity of CambridgeCambridgeUK
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70
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Yu W, Pati D, Pina MM, Schmidt KT, Boyt KM, Hunker AC, Zweifel LS, McElligott ZA, Kash TL. Periaqueductal gray/dorsal raphe dopamine neurons contribute to sex differences in pain-related behaviors. Neuron 2021; 109:1365-1380.e5. [PMID: 33740416 PMCID: PMC9990825 DOI: 10.1016/j.neuron.2021.03.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/02/2021] [Accepted: 02/26/2021] [Indexed: 02/06/2023]
Abstract
Sex differences in pain severity, response, and pathological susceptibility are widely reported, but the neural mechanisms that contribute to these outcomes remain poorly understood. Here we show that dopamine (DA) neurons in the ventrolateral periaqueductal gray/dorsal raphe (vlPAG/DR) differentially regulate pain-related behaviors in male and female mice through projections to the bed nucleus of the stria terminalis (BNST). We find that activation of vlPAG/DRDA+ neurons or vlPAG/DRDA+ terminals in the BNST reduces nociceptive sensitivity during naive and inflammatory pain states in male mice, whereas activation of this pathway in female mice leads to increased locomotion in the presence of salient stimuli. We additionally use slice physiology and genetic editing approaches to demonstrate that vlPAG/DRDA+ projections to the BNST drive sex-specific responses to pain through DA signaling, providing evidence of a novel ascending circuit for pain relief in males and contextual locomotor response in females.
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Affiliation(s)
- Waylin Yu
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Dipanwita Pati
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Melanie M Pina
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Karl T Schmidt
- Department of Psychiatry, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kristen M Boyt
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Avery C Hunker
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Larry S Zweifel
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA
| | - Zoe A McElligott
- Department of Psychiatry, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Thomas L Kash
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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71
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Huang J, Zhang Z, Gambeta E, Chen L, Zamponi GW. An orbitofrontal cortex to midbrain projection modulates hypersensitivity after peripheral nerve injury. Cell Rep 2021; 35:109033. [PMID: 33910011 DOI: 10.1016/j.celrep.2021.109033] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 02/01/2021] [Accepted: 04/02/2021] [Indexed: 12/28/2022] Open
Abstract
Neuropathic pain is a debilitating condition that is often refractory to treatment. The network of neural substrates for pain transmission and control within the brain is complex and remains poorly understood. Through a combination of neuronal tracing, optogenetics, chemogenetics, electrophysiological recordings, and behavioral assessment, we demonstrate that activation of layer 5 pyramidal neurons in the ventrolateral orbitofrontal cortex (vlOFC) attenuates mechanical and thermal hypersensitivity and cold allodynia in mice with neuropathic pain induced by spared nerve injury (SNI). These vlOFC output neurons project to the posterior ventrolateral periaqueductal gray (vlPAG) region and receive inputs from the ventromedial thalamus (VM). Specific optogenetic and chemogenetic activation of the vlOFC-vlPAG and the VM-vlOFC circuits inhibits hypersensitivity associated with neuropathy. Thus, we reveal a modulatory role of the vlOFC and its projections to the vlPAG circuit in the processing of hypersensitive nociception.
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Affiliation(s)
- Junting Huang
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong 510080, China; Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada.
| | - Zizhen Zhang
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Eder Gambeta
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Lina Chen
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Gerald W Zamponi
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada.
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72
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Yin JB, Liang SH, Li F, Zhao WJ, Bai Y, Sun Y, Wu ZY, Ding T, Sun Y, Liu HX, Lu YC, Zhang T, Huang J, Chen T, Li H, Chen ZF, Cao J, Ren R, Peng YN, Yang J, Zang WD, Li X, Dong YL, Li YQ. dmPFC-vlPAG projection neurons contribute to pain threshold maintenance and antianxiety behaviors. J Clin Invest 2021; 130:6555-6570. [PMID: 32841213 DOI: 10.1172/jci127607] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 08/20/2020] [Indexed: 12/21/2022] Open
Abstract
The dorsal medial prefrontal cortex (dmPFC) has been recognized as a key cortical area for nociceptive modulation. However, the underlying neural pathway and the function of specific cell types remain largely unclear. Here, we show that lesions in the dmPFC induced an algesic and anxious state. Using multiple tracing methods including a rabies-based transsynaptic tracing method, we outlined an excitatory descending neural pathway from the dmPFC to the ventrolateral periaqueductal gray (vlPAG). Specific activation of the dmPFC/vlPAG neural pathway by optogenetic manipulation produced analgesic and antianxiety effects in a mouse model of chronic pain. Inhibitory neurons in the dmPFC were specifically activated using a chemogenetic approach, which logically produced an algesic and anxious state under both normal and chronic pain conditions. Antagonists of the GABAA receptor (GABAAR) or mGluR1 were applied to the dmPFC, which produced analgesic and antianxiety effects. In summary, the results of our study suggest that the dmPFC/vlPAG neural pathway might participate in the maintenance of pain thresholds and antianxiety behaviors under normal conditions, while silencing or suppressing the dmPFC/vlPAG pathway might be involved in the initial stages and maintenance of chronic pain and the emergence of anxiety-like behaviors.
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Affiliation(s)
- Jun-Bin Yin
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China.,Department of Neurology, the 960th Hospital of PLA, Jinan, China.,Center for the Study of Itch, Washington University School of Medicine, St. Louis, Missouri, USA.,Key Laboratory of Brain Science Research and Transformation in the Tropical Environment of Hainan Province, Haikou, China
| | - Shao-Hua Liang
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China.,Department of Human Anatomy, Binzhou Medical College, Yantai, China
| | - Fei Li
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China.,Cadet Brigade, and
| | - Wen-Jun Zhao
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China.,Cadet Brigade, and
| | - Yang Bai
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China.,Center for the Study of Itch, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Yi Sun
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China.,Center for the Study of Itch, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Human Anatomy, Binzhou Medical College, Yantai, China
| | - Zhen-Yu Wu
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China.,Center for the Study of Itch, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Tan Ding
- Department of Orthopedics, Xijing Hospital, the Fourth Military Medical University, Xi'an, China
| | | | - Hai-Xia Liu
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Ya-Cheng Lu
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Ting Zhang
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Jing Huang
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Tao Chen
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Hui Li
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China.,Center for the Study of Itch, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Zhou-Feng Chen
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jing Cao
- Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, China
| | - Rui Ren
- Key Laboratory of Brain Science Research and Transformation in the Tropical Environment of Hainan Province, Haikou, China
| | - Ya-Nan Peng
- Key Laboratory of Brain Science Research and Transformation in the Tropical Environment of Hainan Province, Haikou, China
| | - Juan Yang
- Key Laboratory of Brain Science Research and Transformation in the Tropical Environment of Hainan Province, Haikou, China
| | - Wei-Dong Zang
- Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, China
| | - Xiang Li
- Department of Orthopaedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yu-Lin Dong
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Yun-Qing Li
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China.,Key Laboratory of Brain Science Research and Transformation in the Tropical Environment of Hainan Province, Haikou, China.,Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, China
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73
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Cortical Modulation of Nociception. Neuroscience 2021; 458:256-270. [PMID: 33465410 DOI: 10.1016/j.neuroscience.2021.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 11/28/2020] [Accepted: 01/03/2021] [Indexed: 02/06/2023]
Abstract
Nociception is the neuronal process of encoding noxious stimuli and could be modulated at peripheral, spinal, brainstem, and cortical levels. At cortical levels, several areas including the anterior cingulate cortex (ACC), prefrontal cortex (PFC), ventrolateral orbital cortex (VLO), insular cortex (IC), motor cortex (MC), and somatosensory cortices are involved in nociception modulation through two main mechanisms: (i) a descending modulatory effect at spinal level by direct corticospinal projections or mostly by activation of brainstem structures (i.e. periaqueductal grey matter (PAG), locus coeruleus (LC), the nucleus of raphe (RM) and rostroventral medulla (RVM)); and by (ii) cortico-cortical or cortico-subcortical interactions. This review summarizes evidence related to the participation of the aforementioned cortical areas in nociception modulation and different neurotransmitters or neuromodulators that have been studied in each area. Besides, we point out the importance of considering intracortical neuronal populations and receptors expression, as well as, nociception-induced cortical changes, both functional and connectional, to better understand this modulatory effect. Finally, we discuss the possible mechanisms that could potentiate the use of cortical stimulation as a promising procedure in pain alleviation.
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74
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Falconi-Sobrinho LL, Dos Anjos-Garcia T, Coimbra NC. Nitric oxide-mediated defensive and antinociceptive responses organised at the anterior hypothalamus of mice are modulated by glutamatergic inputs from area 24b of the cingulate cortex. J Psychopharmacol 2021; 35:78-90. [PMID: 33300404 DOI: 10.1177/0269881120967881] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Previous studies suggested that Cg1 area of the cingulate cortex of rats controls glutamate-mediated fear-induced defensive behaviour and antinociception organised at the posterior hypothalamus. In turn, microinjection of the nitric oxide donor SIN-1 into the anterior hypothalamus of mice produced defensive behaviours and fear-induced antinociception. However, it remains unknown whether Cg1 also modulates the latter mechanisms in mice. AIMS The present study examined the influence of Cg1 on SIN1-evoked fear-induced defensive behaviour and antinociception organised at the anterior hypothalamus of mice. METHODS The fear-like behavioural and antinociceptive responses to the microinjection of SIN-1 (300 nmol) into the anterior hypothalamus were evaluated after the microinjection of either N-methyl-D-aspartic acid receptor agonist (0.1, 1 and 10 nmol) or physiological saline into the cingulate cortex of C57BL/6 male mice. In addition, neurotracing and immunohistochemistry were used to characterise Cg1-anterior hypothalamus glutamatergic pathways. RESULTS The data showed that activation of Cg1 N-methyl-D-aspartic acid receptors increased escape while reducing freezing and antinociceptive responses to SIN-1 microinjections into the anterior hypothalamus. Anterograde neural tract tracer co-localised with VGLUT2-labelled fibres suggests these responses are mediated by glutamatergic synapses at the anterior hypothalamus. CONCLUSIONS In contrast with previous studies showing that Cg1 facilitates both escape and antinociception to chemical stimulation of the posterior hypothalamus in rats, the present data suggest that Cg1 facilitates escape while inhibiting defensive antinociception produced by the microinjection of SIN-1 in the anterior hypothalamus of mice. Accordingly, Cg1 may have opposite effects on antinociceptive responses organised in the anterior and posterior hypothalamus of mice and rats, respectively.
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Affiliation(s)
- Luiz Luciano Falconi-Sobrinho
- Department of Pharmacology, Laboratory of Neuroanatomy and Neuropsychobiology, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto, São Paulo, Brasil.,NAP-USP-Neurobiology of Emotions Research Centre, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto, São Paulo, Brasil.,Behavioural Neurosciences Institute, Ribeirão Preto, São Paulo, Brasil
| | - Tayllon Dos Anjos-Garcia
- Department of Pharmacology, Laboratory of Neuroanatomy and Neuropsychobiology, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto, São Paulo, Brasil.,NAP-USP-Neurobiology of Emotions Research Centre, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto, São Paulo, Brasil
| | - Norberto Cysne Coimbra
- Department of Pharmacology, Laboratory of Neuroanatomy and Neuropsychobiology, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto, São Paulo, Brasil.,NAP-USP-Neurobiology of Emotions Research Centre, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto, São Paulo, Brasil.,Behavioural Neurosciences Institute, Ribeirão Preto, São Paulo, Brasil
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75
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Supraspinal Mechanisms of Intestinal Hypersensitivity. Cell Mol Neurobiol 2020; 42:389-417. [PMID: 33030712 DOI: 10.1007/s10571-020-00967-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022]
Abstract
Gut inflammation or injury causes intestinal hypersensitivity (IHS) and hyperalgesia, which can persist after the initiating pathology resolves, are often referred to somatic regions and exacerbated by psychological stress, anxiety or depression, suggesting the involvement of both the spinal cord and the brain. The supraspinal mechanisms of IHS remain to be fully elucidated, however, over the last decades the series of intestinal pathology-associated neuroplastic changes in the brain has been revealed, being potentially responsible for the phenomenon. This paper reviews current clinical and experimental data, including the authors' own findings, on these functional, structural, and neurochemical/molecular changes within cortical, subcortical and brainstem regions processing and modulating sensory signals from the gut. As concluded in the review, IHS can develop and maintain due to the bowel inflammation/injury-induced persistent hyperexcitability of viscerosensory brainstem and thalamic nuclei and sensitization of hypothalamic, amygdala, hippocampal, anterior insular, and anterior cingulate cortical areas implicated in the neuroendocrine, emotional and cognitive modulation of visceral sensation and pain. An additional contribution may come from the pathology-triggered dysfunction of the brainstem structures inhibiting nociception. The mechanism underlying IHS-associated regional hyperexcitability is enhanced NMDA-, AMPA- and group I metabotropic receptor-mediated glutamatergic neurotransmission in association with altered neuropeptide Y, corticotropin-releasing factor, and cannabinoid 1 receptor signaling. These alterations are at least partially mediated by brain microglia and local production of cytokines, especially tumor necrosis factor α. Studying the IHS-related brain neuroplasticity in greater depth may enable the development of new therapeutic approaches against chronic abdominal pain in inflammatory bowel disease.
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76
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Waung MW, Margolis EB, Charbit AR, Fields HL. A Midbrain Circuit that Mediates Headache Aversiveness in Rats. Cell Rep 2020; 28:2739-2747.e4. [PMID: 31509737 PMCID: PMC6831085 DOI: 10.1016/j.celrep.2019.08.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 06/07/2019] [Accepted: 07/24/2019] [Indexed: 01/05/2023] Open
Abstract
Migraines are a major health burden, but treatment is limited because of inadequate understanding of neural mechanisms underlying headache. Imaging studies of migraine patients demonstrate changes in both pain-modulatory circuits and reward-processing regions, but whether these changes contribute to the experience of headache is unknown. Here, we demonstrate a direct connection between the ventrolateral periaqueductal gray (vlPAG) and the ventral tegmental area (VTA) that contributes to headache aversiveness in rats. Many VTA neurons receive monosynaptic input from the vlPAG, and cranial nociceptive input increases Fos expression in VTA-projecting vlPAG neurons. Activation of PAG inputs to the VTA induces avoidance behavior, while inactivation of these projections induces a place preference only in animals with headache. This work identifies a distinct pathway that mediates cranial nociceptive aversiveness. Migraine headache is a common and debilitating disorder, yet its brain-activation patterns are poorly understood. Waung et al. discover that headache activates a connection between the periaqueductal gray and the ventral tegmental area in rats. Turning off this connection has no effect normally but decreases unpleasantness during headaches.
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Affiliation(s)
- Maggie W Waung
- Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Elyssa B Margolis
- Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Annabelle R Charbit
- Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Howard L Fields
- Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
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77
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Abstract
A recently defined structure, the rostromedial tegmental nucleus (RMTg; aka tail of the ventral tegmental area [VTA]), has been proposed as an inhibitory control center for dopaminergic activity of the VTA. This region is composed of GABAergic cells that send afferent projections to the ventral midbrain and synapse onto dopaminergic cells in the VTA and substantia nigra. These cells exhibit µ-opioid receptor immunoreactivity, and in vivo, ex vivo, and optogenetic/electrophysiological approaches demonstrate that morphine excites dopamine neurons by targeting receptors on GABAergic neurons localized in the RMTg. This suggests that the RMTg may be a key modulator of opioid effects and a major brake regulating VTA dopamine systems. However, no study has directly manipulated RMTg GABAergic neurons in vivo and assessed the effect on nociception or opioid analgesia. In this study, multiplexing of GABAergic neurons in the RMTg was achieved using stimulatory Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) and inhibitory kappa-opioid receptor DREADDs (KORD). Our data show that locally infused RMTg morphine or selective RMTg GABAergic neuron inhibition produces 87% of the maximal antinociceptive effect of systemic morphine, and RMTg GABAergic neurons modulate dopamine release in the nucleus accumbens. In addition, chemoactivation of VTA dopamine neurons significantly reduced pain behaviors both in resting and facilitated pain states and reduced by 75% the dose of systemic morphine required to produce maximal antinociception. These results provide compelling evidence that RMTg GABAergic neurons are involved in processing of nociceptive information and are important mediators of opioid analgesia.
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78
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Marciante AB, Farmer GE, Cunningham JT. G q DREADD activation of CaMKIIa MnPO neurons stimulates nitric oxide activity. J Neurophysiol 2020; 124:591-609. [PMID: 32697679 PMCID: PMC7500373 DOI: 10.1152/jn.00239.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/30/2020] [Accepted: 06/30/2020] [Indexed: 11/22/2022] Open
Abstract
Designer receptors exclusively activated by designer drugs (DREADDs) modify cellular activity following administration of the exogenous ligand clozapine-N-oxide (CNO). However, some reports indicate CNO may have off-target effects. The current studies investigate the use of Gq DREADDs in CaMKIIa-expressing neurons in the median preoptic nucleus (MnPO). Male Sprague-Dawley rats (250 g) anesthetized with isoflurane were stereotaxically microinjected in the MnPO with the Gq DREADD (AAV5-CaMKIIa-HM3D-mCherry) or control virus (AAV5-CaMKIIa-mCherry). Following a 2-wk recovery, rats were used for either immunohistochemical Fos analysis or in vitro patch-clamp electrophysiology. In Gq DREADD-injected rats, CNO induced significant increases in Fos staining in the MnPO and in regions that receive direct or indirect projections from the MnPO. In electrophysiological studies, CNO depolarized and augmented firing frequency in both Gq DREADD-positive neurons (Gq DREADD) as well as unlabeled MnPO neurons in slices from Gq DREADD-injected rats (Gq DREADDx). Gq DREADDx neurons also displayed increases in spontaneous postsynaptic current (sPSC) frequency in response to CNO. Additionally, CaMKIIa-positive MnPO neurons, which also express nitric oxide synthase (NOS), were treated with Nω-nitro-l-arginine (l-NNA; competitive inhibitor of NOS) and hemoglobin (NO scavenger) to assess the role of NO in Gq DREADDx neuron recruitment. Both l-NNA and hemoglobin blocked CNO-induced effects in Gq DREADDx neurons without affecting Gq DREADD neurons. These findings indicate that Gq DREADD-mediated activation of CaMKIIa/NOS expressing neurons in the MnPO can influence the activity of neighboring neurons. Future studies utilizing the use of Gq DREADDs will need to consider the potential recruitment of additional cell populations.NEW & NOTEWORTHY Rats were injected in the median preoptic nucleus (MnPO) with either an adeno-associated virus (AAV) and excitatory (Gq) designer receptor exclusively activated by designer drugs (DREADD) construct or a control AAV. In the Gq DREADD-injected rats only, clozapine-N-oxide (CNO) increased Fos staining in the MnPO and its targets and increased neuron action potential frequency. In electrophysiology experiments with slices with DREADD cells, unlabeled cells were activated and this was likely due to nitric oxide release by the DREADD cells.
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Affiliation(s)
- Alexandria B Marciante
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Fort Worth, Texas
| | - George E Farmer
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Fort Worth, Texas
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79
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Agostinelli LJ, Mix MR, Hefti MM, Scammell TE, Bassuk AG. Input-output connections of LJA5 prodynorphin neurons. J Comp Neurol 2020; 529:635-654. [PMID: 32602558 PMCID: PMC7769903 DOI: 10.1002/cne.24974] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 06/22/2020] [Accepted: 06/25/2020] [Indexed: 12/21/2022]
Abstract
Sensory information is transmitted from peripheral nerves, through the spinal cord, and up to the brain. Sensory information may be modulated by projections from the brain to the spinal cord, but the neural substrates for top‐down sensory control are incompletely understood. We identified a novel population of inhibitory neurons in the mouse brainstem, distinguished by their expression of prodynorphin, which we named LJA5. Here, we identify a similar group of Pdyn+ neurons in the human brainstem, and we define the efferent and afferent projection patterns of LJA5 neurons in mouse. Using specific genetic tools, we selectively traced the projections of the Pdyn‐expressing LJA5 neurons through the brain and spinal cord. Terminal fields were densest in the lateral and ventrolateral periaqueductal gray (PAG), lateral parabrachial nucleus (LPB), caudal pressor area, and lamina I of the spinal trigeminal nucleus and all levels of the spinal cord. We then labeled cell types in the PAG, LPB, medulla, and spinal cord to better define the specific targets of LJA5 boutons. LJA5 neurons send the only known inhibitory descending projection specifically to lamina I of the spinal cord, which transmits afferent pain, temperature, and itch information up to the brain. Using retrograde tracing, we found LJA5 neurons receive inputs from sensory and stress areas such as somatosensory/insular cortex, preoptic area, paraventricular nucleus, dorsomedial nucleus and lateral hypothalamus, PAG, and LPB. This pattern of inputs and outputs suggest LJA5 neurons are uniquely positioned to be activated by sensation and stress, and in turn, inhibit pain and itch.
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Affiliation(s)
- Lindsay J Agostinelli
- Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USA.,Department of Pediatrics, University of Iowa, Iowa City, Iowa, USA.,Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Madison R Mix
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, USA
| | - Marco M Hefti
- Department of Pathology, University of Iowa, Iowa City, Iowa, USA
| | - Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Alexander G Bassuk
- Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USA.,Department of Pediatrics, University of Iowa, Iowa City, Iowa, USA
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80
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Abstract
Itch, in particular chronic forms, has been widely recognized as an important clinical problem, but much less is known about the mechanisms of itch in comparison with other sensory modalities such as pain. Recently, considerable progress has been made in dissecting the circuit mechanisms of itch at both the spinal and supraspinal levels. Major components of the spinal neural circuit underlying both chemical and mechanical itch have now been identified, along with the circuits relaying ascending transmission and the descending modulation of itch. In this review, we summarize the progress in elucidating the neural circuit mechanism of itch at spinal and supraspinal levels.
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Affiliation(s)
- Xiao-Jun Chen
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, 200031, Shanghai, China
- University of Chinese Academy of Sciences, 19A Yu-quan Road, 100049, Beijing, China
| | - Yan-Gang Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, 200031, Shanghai, China.
- Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, 201210, Shanghai, China.
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81
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Kuner R, Kuner T. Cellular Circuits in the Brain and Their Modulation in Acute and Chronic Pain. Physiol Rev 2020; 101:213-258. [PMID: 32525759 DOI: 10.1152/physrev.00040.2019] [Citation(s) in RCA: 149] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Chronic, pathological pain remains a global health problem and a challenge to basic and clinical sciences. A major obstacle to preventing, treating, or reverting chronic pain has been that the nature of neural circuits underlying the diverse components of the complex, multidimensional experience of pain is not well understood. Moreover, chronic pain involves diverse maladaptive plasticity processes, which have not been decoded mechanistically in terms of involvement of specific circuits and cause-effect relationships. This review aims to discuss recent advances in our understanding of circuit connectivity in the mammalian brain at the level of regional contributions and specific cell types in acute and chronic pain. A major focus is placed on functional dissection of sub-neocortical brain circuits using optogenetics, chemogenetics, and imaging technological tools in rodent models with a view towards decoding sensory, affective, and motivational-cognitive dimensions of pain. The review summarizes recent breakthroughs and insights on structure-function properties in nociceptive circuits and higher order sub-neocortical modulatory circuits involved in aversion, learning, reward, and mood and their modulation by endogenous GABAergic inhibition, noradrenergic, cholinergic, dopaminergic, serotonergic, and peptidergic pathways. The knowledge of neural circuits and their dynamic regulation via functional and structural plasticity will be beneficial towards designing and improving targeted therapies.
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Affiliation(s)
- Rohini Kuner
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany; and Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Thomas Kuner
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany; and Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
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82
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Bagley EE, Ingram SL. Endogenous opioid peptides in the descending pain modulatory circuit. Neuropharmacology 2020; 173:108131. [PMID: 32422213 DOI: 10.1016/j.neuropharm.2020.108131] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 05/01/2020] [Accepted: 05/04/2020] [Indexed: 02/07/2023]
Abstract
The opioid epidemic has led to a serious examination of the use of opioids for the treatment of pain. Opioid drugs are effective due to the expression of opioid receptors throughout the body. These receptors respond to endogenous opioid peptides that are expressed as polypeptide hormones that are processed by proteolytic cleavage. Endogenous opioids are expressed throughout the peripheral and central nervous system and regulate many different neuronal circuits and functions. One of the key functions of endogenous opioid peptides is to modulate our responses to pain. This review will focus on the descending pain modulatory circuit which consists of the ventrolateral periaqueductal gray (PAG) projections to the rostral ventromedial medulla (RVM). RVM projections modulate incoming nociceptive afferents at the level of the spinal cord. Stimulation within either the PAG or RVM results in analgesia and this circuit has been studied in detail in terms of the actions of exogenous opioids, such as morphine and fentanyl. Further emphasis on understanding the complex regulation of endogenous opioids will help to make rational decisions with regard to the use of opioids for pain. We also include a discussion of the actions of endogenous opioids in the amygdala, an upstream brain structure that has reciprocal connections to the PAG that contribute to the brain's response to pain.
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Affiliation(s)
- Elena E Bagley
- Discipline of Pharmacology and Charles Perkins Centre, University of Sydney, NSW, 2006, Australia
| | - Susan L Ingram
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR, 97239, USA.
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83
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George Zaki Ghali M. Midbrain control of breathing and blood pressure: The role of periaqueductal gray matter and mesencephalic collicular neuronal microcircuit oscillators. Eur J Neurosci 2020; 52:3879-3902. [PMID: 32227408 DOI: 10.1111/ejn.14727] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 02/01/2020] [Accepted: 03/22/2020] [Indexed: 01/12/2023]
Abstract
Neural circuitry residing within the medullary ventral respiratory column nuclei and dorsal respiratory group interact with the Kölliker-Fuse and medial parabrachial nuclei to generate the core breathing rhythm and pattern during resting conditions. Triphasic eupnea consists of inspiratory [I], post-inspiratory [post-I], and late-expiratory [E2] phases. Mesencephalic zones exert modulatory influences upon respiratory rhythm-generating circuitry, sympathetic oscillators, and parasympathetic nuclei. The earliest evidence supporting the existence of midbrain control of breathing derives from studies conducted by Martin and Booker in 1878. These authors demonstrated electrical stimulation of the deep layers of the mesencephalic colliculi in the rabbit augmented ventilation and sequentially elicited chest wall tremors and tetany. Investigations performed during the past several decades would demonstrate stimlation of distributed zones within the midbrain reticular formation elicits starkly disparate effects upon respiratory phase switching. Schmid, Böhmer, and Fallert demonstrated electrical stimulation of the nucleus rubre and emanating axon bundles alternately elicits or inhibits the activity of medullary expiratory- or inspiratory-related units and phrenic nerve discharge with differential latency. A series of studies would later indicate the red nucleus mediates hypoxic ventilatory depression. Periaqueductal gray matter neurons exhibit extensive afferent and efferent interconnectivity with suprabulbar, brainstem, and spinal cord zones aptly positioning these units to modulate breathing, autonomic outflow, nociception locomotion, micturtion, and sexual behavior. Experimental stimulatory activation of the tectal colliculi and periaqueductal gray matter via electrical current or glutamate, D,L-homocysteinic acid, or bicuculline microinjections coordinately modulates neuromotor inspiratory bursting frequency and amplitude and discharge of pre-Bötzinger complex, ventrolateral medullary late-I and post-I, and ventrolateral nucleus tractus solitarius decrementing early-I and augmenting and decrementing late-I neurons, elicits expiratory outflow and vocalization, and blunt the Hering-Breuer reflex in unanesthetzed decerebrate and anesthetized preprations of the cat and rat. Stimulation of the mesencephalic colliuli or dorsal divisions of the PAG potently amplifes renal sympathetic neural efferent activity, dynamic arterial pressure magnitude, and myocardial contraction frequency and elicits various behavioral defense responses. Elicited physiological effects exhibit extensive locoregional heterogeneity and variably enlist requisite contributions from the dorsomedial hypothalamus and/or lateral parabrachial nuclei. Stimulation of the dorsal mesencephalon occasionally elicits dynamic increases of arterial pressure magnitude exhibiting prominent oscillatory variability coherent with phrenic nerve discharge, perhaps by generating intra-neuraxial hysteresis, serving to intermittently deliver blood to organ vascular beds under high pressure in order to prevent organ edema, microcirculatory dysfunction, and downregulation of vascular smooth muscle alpha adrenergic receptors. Chemosensitive mesencephalic caudal raphé units and projections of hypoxia-sensitive units in the caudal hypothalamus to the periaqueductal gray matter may imply the existence of a diencephalo-smesencephalic chemosensitive network modulating breathing and sympathetic discharge.
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Affiliation(s)
- Michael George Zaki Ghali
- Department of Neurological Surgery, Baylor College of Medicine, Houston, Texas.,Department of Neurological Surgery, University of California, San Francisco, California.,Department of Neurological Surgery, Karolinska Institutet, Stockholm, Sweden
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84
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Uniyal A, Gadepalli A, Akhilesh, Tiwari V. Underpinning the Neurobiological Intricacies Associated with Opioid Tolerance. ACS Chem Neurosci 2020; 11:830-839. [PMID: 32083459 DOI: 10.1021/acschemneuro.0c00019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The opioid crisis is a major threat of the 21st century, with a remarkable juxtaposition of use and abuse. Opioids are the most potent and efficacious class of analgesics, but despite their proven therapeutic efficacy, they have recently been degraded to third-line therapy for the management of chronic pain in clinics. The reason behind this is the development of potential side effects and tolerance after repeated dosing. Opioid tolerance is the major limiting factor leading to the withdrawal of treatment, severe side effects due to dose escalation, and sometimes even death of the patients. Every day more than 90 people die due to opioids overdose in America, and a similar trend has been seen across the globe. Over the past two decades, researchers have been trying to dissect the neurobiological mechanism of opioid tolerance. Research on opioid tolerance shifted toward central nervous system-based adaptations because tolerance is much more than just a cellular phenomenon. Thus, neurobiological adaptations associated with opioid tolerance are important to understand in order to find newer pain therapeutics. These adaptations are associated with alterations in ascending and descending pain pathways, reward circuitry modulations, receptor desensitization and down-regulation, receptor internalization, heterodimerization, and altered epigenetic regulation. The present Review is focused on novel circuitries associated with opioid tolerance in different areas of the brain, such as periaqueductal gray, rostral ventromedial medulla, dorsal raphe nucleus, ventral tegmental area, and nucleus accumbens. Understanding the neurobiological modulations associated with chronic opioid exposure and tolerance will pave the way for the development of novel pharmacological tools for safer and better management of chronic pain in patients.
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Affiliation(s)
- Ankit Uniyal
- Neuroscience & Pain Research Laboratory, Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University Varanasi-221005, Uttar Pradesh, India
| | - Anagha Gadepalli
- Neuroscience & Pain Research Laboratory, Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University Varanasi-221005, Uttar Pradesh, India
| | - Akhilesh
- Neuroscience & Pain Research Laboratory, Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University Varanasi-221005, Uttar Pradesh, India
| | - Vinod Tiwari
- Neuroscience & Pain Research Laboratory, Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University Varanasi-221005, Uttar Pradesh, India
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85
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St Laurent R, Martinez Damonte V, Tsuda AC, Kauer JA. Periaqueductal Gray and Rostromedial Tegmental Inhibitory Afferents to VTA Have Distinct Synaptic Plasticity and Opiate Sensitivity. Neuron 2020; 106:624-636.e4. [PMID: 32191871 DOI: 10.1016/j.neuron.2020.02.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 10/01/2019] [Accepted: 02/25/2020] [Indexed: 12/16/2022]
Abstract
The ventral tegmental area (VTA) is a major target of addictive drugs and receives multiple GABAergic projections originating outside the VTA. We describe differences in synaptic plasticity and behavior when optogenetically driving two opiate-sensitive GABAergic inputs to the VTA, the rostromedial tegmental nucleus (RMTg), and the periaqueductal gray (PAG). Activation of GABAergic RMTg terminals in the VTA in vivo is aversive, and low-frequency stimulation induces long-term depression in vitro. Low-frequency stimulation of PAG afferents in vitro unexpectedly causes long-term potentiation. Opioid receptor activation profoundly depresses PAG and RMTg inhibitory synapses but prevents synaptic plasticity only at PAG synapses. Activation of the GABAergic PAG terminals in the VTA promotes immobility, and optogenetically-driven immobility is blocked by morphine. Our data reveal the PAG as a source of highly opioid-sensitive GABAergic afferents and support the idea that different GABAergic pathways to the VTA control distinct behaviors.
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Affiliation(s)
- Robyn St Laurent
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94035, USA
| | - Valentina Martinez Damonte
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94035, USA
| | - Ayumi C Tsuda
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI 02912, USA
| | - Julie A Kauer
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94035, USA.
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86
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Cazuza RA, Santos-Júnior NN, da Costa LHA, Catalão CHR, Mendes-Gomes J, da Rocha MJA, Leite-Panissi CRA. Sepsis-induced encephalopathy impairs descending nociceptive pathways in rats. J Neuroimmunol 2020; 342:577198. [PMID: 32120082 DOI: 10.1016/j.jneuroim.2020.577198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 02/19/2020] [Accepted: 02/24/2020] [Indexed: 12/16/2022]
Abstract
Sepsis-associated encephalopathy (SAE) is a significant problem in patients with sepsis, and it is associated with a decrease in cognitive and sensitivity capability induced by systemic inflammation. SAE is implicated in reversible brain damage of several regions related to cognition, emotion, and sensation; however, it is not well established if it could affect brain regions associated with nociceptive modulation. Here were evaluated the nociceptive thresholds in rats with systemic inflammation induced by cecal ligation puncture (CLP). After 24 h of CLP, it was observed an increase in nociceptive threshold in all tests. Periaqueductal gray, rostroventral medulla, critical regions for descending nociceptive modulation, were evaluated and showed enhanced pro-inflammatory cytokines as well as glial activation. These results suggest that systemic inflammation could compromise descending facilitatory pathways, impairing nociceptive sensory functioning.
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Affiliation(s)
- Rafael Alves Cazuza
- Department of Psychology, School of Philosophy, Science and Literature of Ribeirão Preto, University of São Paulo, Ribeirão Preto, 14040-901, SP, Brazil
| | - Nilton Nascimento Santos-Júnior
- Department of Basic and Oral Biology, Ribeirão Preto Dentistry Faculty, University of São Paulo, Ribeirão Preto 14040-904, SP, Brazil
| | - Luís Henrique Angenendt da Costa
- Department of Basic and Oral Biology, Ribeirão Preto Dentistry Faculty, University of São Paulo, Ribeirão Preto 14040-904, SP, Brazil; Department of Neurosciences and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil
| | - Carlos Henrique Rocha Catalão
- Department of Basic and Oral Biology, Ribeirão Preto Dentistry Faculty, University of São Paulo, Ribeirão Preto 14040-904, SP, Brazil; Department of Neurosciences and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil
| | - Joyce Mendes-Gomes
- Department of Psychology, School of Philosophy, Science and Literature of Ribeirão Preto, University of São Paulo, Ribeirão Preto, 14040-901, SP, Brazil; UNIFADRA-FUNDEC Medical School, Dracena 17900-000, SP, Brazil
| | - Maria José Alves da Rocha
- Department of Basic and Oral Biology, Ribeirão Preto Dentistry Faculty, University of São Paulo, Ribeirão Preto 14040-904, SP, Brazil
| | - Christie Ramos Andrade Leite-Panissi
- Department of Psychology, School of Philosophy, Science and Literature of Ribeirão Preto, University of São Paulo, Ribeirão Preto, 14040-901, SP, Brazil.
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87
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Lau BK, Winters BL, Vaughan CW. Opioid presynaptic disinhibition of the midbrain periaqueductal grey descending analgesic pathway. Br J Pharmacol 2020; 177:2320-2332. [PMID: 31971607 DOI: 10.1111/bph.14982] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 12/10/2019] [Accepted: 12/18/2019] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND PURPOSE The midbrain periaqueductal grey (PAG) plays a central role in modulating pain through a descending pathway that projects indirectly to the spinal cord via the rostroventral medial medulla (RVM). While opioids are potent analgesics that target the PAG, their cellular actions on descending projection neurons are unclear. EXPERIMENTAL APPROACH Patch clamp recordings in voltage- and current-clamp mode were made from acutely prepared PAG slices from animals that received retrograde tracer injections into the RVM. KEY RESULTS The μ-agonist DAMGO reduced GABAergic evoked inhibitory postsynaptic currents (IPSCs) in retro-labelled, RVM-projecting neurons to a greater extent than in unlabelled neurons. The κ-opioid agonist U69593 reduced evoked IPSCs to a similar extent in both neuronal groups, while the δ-opioid agonist deltorphin-II was without effect. DAMGO and U69593 both produced a reduction in the rate, but not amplitude of spontaneous miniature IPSCs and asynchronous evoked IPSCs in retro-labelled neurons. DAMGO and U69593 also suppressed glutamatergic EPSCs in retro-labelled and unlabelled neurons. The DAMGO inhibition of evoked EPSCs, however, was less than that for evoked IPSCs in retro-labelled, but not unlabelled neurons. In current clamp, DAMGO produced a depolarizing increase in evoked postsynaptic potentials in retro-labelled neurons, but directly inhibited unlabelled neurons. CONCLUSION AND IMPLICATIONS These findings suggest that μ-opioids activate the descending analgesic pathway from the midbrain PAG by a combination of presynaptic disinhibition of RVM-projecting neurons and postsynaptic inhibition of presumptive interneurons.
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Affiliation(s)
- Benjamin K Lau
- Pain Management Research Institute and Kolling Institute of Medical Research, The University of Sydney at Royal North Shore Hospital, St. Leonards, New South Wales, Australia
| | - Bryony L Winters
- Pain Management Research Institute and Kolling Institute of Medical Research, The University of Sydney at Royal North Shore Hospital, St. Leonards, New South Wales, Australia
| | - Christopher W Vaughan
- Pain Management Research Institute and Kolling Institute of Medical Research, The University of Sydney at Royal North Shore Hospital, St. Leonards, New South Wales, Australia
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88
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Binda K, Real C, Ferreira A, Britto L, Chacur M. Antinociceptive effects of treadmill exercise in a rat model of Parkinson's disease: The role of cannabinoid and opioid receptors. Brain Res 2020; 1727:146521. [DOI: 10.1016/j.brainres.2019.146521] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 09/19/2019] [Accepted: 10/21/2019] [Indexed: 12/17/2022]
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89
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Samineni VK, Grajales-Reyes JG, Sundaram SS, Yoo JJ, Gereau RW. Cell type-specific modulation of sensory and affective components of itch in the periaqueductal gray. Nat Commun 2019; 10:4356. [PMID: 31554789 PMCID: PMC6761157 DOI: 10.1038/s41467-019-12316-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 08/28/2019] [Indexed: 01/07/2023] Open
Abstract
Itch is a distinct aversive sensation that elicits a strong urge to scratch. Despite recent advances in our understanding of the peripheral basis of itch, we know very little regarding how central neural circuits modulate acute and chronic itch processing. Here we establish the causal contributions of defined periaqueductal gray (PAG) neuronal populations in itch modulation in mice. Chemogenetic manipulations demonstrate bidirectional modulation of scratching by neurons in the PAG. Fiber photometry studies show that activity of GABAergic and glutamatergic neurons in the PAG is modulated in an opposing manner during chloroquine-evoked scratching. Furthermore, activation of PAG GABAergic neurons or inhibition of glutamatergic neurons resulted in attenuation of scratching in both acute and chronic pruritis. Surprisingly, PAG GABAergic neurons, but not glutamatergic neurons, may encode the aversive component of itch. Thus, the PAG represents a neuromodulatory hub that regulates both the sensory and affective aspects of acute and chronic itch.
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Affiliation(s)
- Vijay K Samineni
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Ave, Box 8054, St. Louis, MO, 63110, USA
- Washington University Pain Center, Washington University School of Medicine, 660 S. Euclid Ave, Box 8054, St. Louis, MO, 63110, USA
| | - Jose G Grajales-Reyes
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Ave, Box 8054, St. Louis, MO, 63110, USA
- Washington University Pain Center, Washington University School of Medicine, 660 S. Euclid Ave, Box 8054, St. Louis, MO, 63110, USA
- Medical Scientist Training Program, Washington University School of Medicine, 660 S. Euclid Ave, Box 8054, St. Louis, MO, 63110, USA
- Neuroscience Program, Washington University School of Medicine, 660 S. Euclid Ave, Box 8054, St. Louis, MO, 63110, USA
| | - Saranya S Sundaram
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Ave, Box 8054, St. Louis, MO, 63110, USA
- Washington University Pain Center, Washington University School of Medicine, 660 S. Euclid Ave, Box 8054, St. Louis, MO, 63110, USA
| | - Judy J Yoo
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Ave, Box 8054, St. Louis, MO, 63110, USA
- Washington University Pain Center, Washington University School of Medicine, 660 S. Euclid Ave, Box 8054, St. Louis, MO, 63110, USA
| | - Robert W Gereau
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Ave, Box 8054, St. Louis, MO, 63110, USA.
- Washington University Pain Center, Washington University School of Medicine, 660 S. Euclid Ave, Box 8054, St. Louis, MO, 63110, USA.
- Department of Neuroscience, Department of Biomedical Engineering, Washington University School of Medicine, 660 S. Euclid Ave, Box 8054, St. Louis, MO, 63110, USA.
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90
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Huang J, Gadotti VM, Chen L, Souza IA, Huang S, Wang D, Ramakrishnan C, Deisseroth K, Zhang Z, Zamponi GW. A neuronal circuit for activating descending modulation of neuropathic pain. Nat Neurosci 2019; 22:1659-1668. [DOI: 10.1038/s41593-019-0481-5] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/25/2019] [Indexed: 11/09/2022]
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91
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Siemian JN, Borja CB, Sarsfield S, Kisner A, Aponte Y. Lateral hypothalamic fast-spiking parvalbumin neurons modulate nociception through connections in the periaqueductal gray area. Sci Rep 2019; 9:12026. [PMID: 31427712 PMCID: PMC6700312 DOI: 10.1038/s41598-019-48537-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/03/2019] [Indexed: 12/21/2022] Open
Abstract
A pivotal role of the lateral hypothalamus (LH) in regulating appetitive and reward-related behaviors has been evident for decades. However, the contributions of LH circuits to other survival behaviors have been less explored. Here we examine how lateral hypothalamic neurons that express the calcium-binding protein parvalbumin (PVALB; LHPV neurons), a small cluster of neurons within the LH glutamatergic circuitry, modulate nociception in mice. We find that photostimulation of LHPV neurons suppresses nociception to an acute, noxious thermal stimulus, whereas photoinhibition potentiates thermal nociception. Moreover, we demonstrate that LHPV axons form functional excitatory synapses on neurons in the ventrolateral periaqueductal gray (vlPAG), and photostimulation of these axons mediates antinociception to both thermal and chemical visceral noxious stimuli. Interestingly, this antinociceptive effect appears to occur independently of opioidergic mechanisms, as antagonism of μ-opioid receptors with systemically-administered naltrexone does not abolish the antinociception evoked by activation of this LHPV→vlPAG pathway. This study directly implicates LHPV neurons in modulating nociception, thus expanding the repertoire of survival behaviors regulated by LH circuits.
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Affiliation(s)
- Justin N Siemian
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224-6823, USA
| | - Cara B Borja
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224-6823, USA
| | - Sarah Sarsfield
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224-6823, USA
| | - Alexandre Kisner
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224-6823, USA
| | - Yeka Aponte
- Neuronal Circuits and Behavior Unit, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224-6823, USA. .,The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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92
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Wang L, Shen J, Cai XT, Tao WW, Wan YD, Li DL, Tan XX, Wang Y. Ventrolateral Periaqueductal Gray Matter Neurochemical Lesion Facilitates Epileptogenesis and Enhances Pain Sensitivity in Epileptic Rats. Neuroscience 2019; 411:105-118. [PMID: 31158436 DOI: 10.1016/j.neuroscience.2019.05.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 05/13/2019] [Accepted: 05/15/2019] [Indexed: 12/31/2022]
Abstract
The ventrolateral periaqueductal gray matter (vlPAG) plays a critical role in the pathogenesis of migraine and few studies have shown that vlPAG might be involved in the pathophysiology of epilepsy. But its roles in epileptogenesis and comorbid relationship between migraine and epilepsy have never been reported. In this study, the impairments of vlPAG neuronal network during spontaneous recurrent seizure (SRS) development after status epilepticus (SE) were investigated, and the pain sensitivity as well as the SRS investigated after neurochemical lesion to vlPAG to determine the role of vlPAG in epileptogenesis and in migraine comorbidity with epilepsy. Neuronal loss and alterations of excitatory and inhibitory neural transmission within vlPAG accompanied the development of epileptogenesis induced by SE. On the other hand, neurochemical lesion to vlPAG enhanced frequency and duration of spontaneous seizure event and frequency of epileptiform inter-ictal spike discharges in electroencephalography (EEG), but decreased pain threshold in epileptic rats. This indicates an involvement of the pain regulating structure, vlPAG, in the pathogenesis of epilepsy. This may imply that vlPAG network alterations could be a possible underlying mechanism of the interactive comorbid relationship between epilepsy and migraine.
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Affiliation(s)
- Lei Wang
- Department of Neurology, Epilepsy and Headache Group, the First Affiliated Hospital of Anhui Medical University, Jixi Road 218, Hefei 230022, China
| | - Jie Shen
- Department of Neurology, Epilepsy and Headache Group, the First Affiliated Hospital of Anhui Medical University, Jixi Road 218, Hefei 230022, China
| | - Xin-Ting Cai
- Department of Neurology, Epilepsy and Headache Group, the First Affiliated Hospital of Anhui Medical University, Jixi Road 218, Hefei 230022, China
| | - Wei-Wei Tao
- Department of Neurology, Epilepsy and Headache Group, the First Affiliated Hospital of Anhui Medical University, Jixi Road 218, Hefei 230022, China
| | - Ya-Di Wan
- Department of Neurology, Epilepsy and Headache Group, the First Affiliated Hospital of Anhui Medical University, Jixi Road 218, Hefei 230022, China
| | - Dong-Lin Li
- Department of Neurology, Epilepsy and Headache Group, the First Affiliated Hospital of Anhui Medical University, Jixi Road 218, Hefei 230022, China
| | - Xiu-Xiu Tan
- Department of Neurology, Epilepsy and Headache Group, the First Affiliated Hospital of Anhui Medical University, Jixi Road 218, Hefei 230022, China
| | - Yu Wang
- Department of Neurology, Epilepsy and Headache Group, the First Affiliated Hospital of Anhui Medical University, Jixi Road 218, Hefei 230022, China; Department of Neurology, the Fourth Affiliated Hospital of Anhui Medical University, Huaihai Avenue 100, Hefei 230000, China.
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93
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Zhu H, Xiang HC, Li HP, Lin LX, Hu XF, Zhang H, Meng WY, Liu L, Chen C, Shu Y, Zhang RY, Zhang P, Si JQ, Li M. Inhibition of GABAergic Neurons and Excitation of Glutamatergic Neurons in the Ventrolateral Periaqueductal Gray Participate in Electroacupuncture Analgesia Mediated by Cannabinoid Receptor. Front Neurosci 2019; 13:484. [PMID: 31156369 PMCID: PMC6533898 DOI: 10.3389/fnins.2019.00484] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/29/2019] [Indexed: 01/26/2023] Open
Abstract
Although electroacupuncture (EA) has become a worldwide practice, little is understood about its precise target in the central nervous system (CNS) and the cell type-specific analgesia mechanism. In the present study, we found that EA has significant antinociceptive effects both in inflammatory and neuropathic pain models. Chemogenetic inhibition of GABAergic neurons in the ventrolateral periaqueductal gray (vlPAG) replicated the effects of EA, whereas the combination of chemogenetic activation of GABAergic neurons and chemogenetic inhibition of glutamatergic neurons in the vlPAG was needed to reverse the effects of EA. Specifically knocking out CB1 receptors on GABAergic neurons in the vlPAG abolished the EA effect on pain hypersensitivity, while specifically knocking out CB1 receptors on glutamatergic neurons attenuated only a small portion of the EA effect. EA synchronously inhibits GABAergic neurons and activates glutamatergic neurons in the vlPAG through CB1 receptors to produce EA-induced analgesia. The CB1 receptors on GABAergic neurons localized in the vlPAG was the basis of the EA effect on pain hypersensitivity. This study provides new experimental evidence that EA can bidirectionally regulate GABAergic neurons and glutamatergic neurons via the CB1 receptors of the vlPAG to produce analgesia effects.
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Affiliation(s)
- He Zhu
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China.,Department of Physiology, Medical College of Shihezi University, Shihezi, China
| | - Hong-Chun Xiang
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Hong-Ping Li
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Li-Xue Lin
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Xue-Fei Hu
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Hong Zhang
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Wang-Yang Meng
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Lu Liu
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Chao Chen
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Yang Shu
- Department of Central Laboratory, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Ru-Yue Zhang
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Pei Zhang
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Jun-Qiang Si
- Department of Physiology, Medical College of Shihezi University, Shihezi, China
| | - Man Li
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
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94
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da Silva JT, Evangelista BG, Venega RA, Seminowicz DA, Chacur M. Anti-NGF treatment can reduce chronic neuropathic pain by changing peripheral mediators and brain activity in rats. Behav Pharmacol 2019; 30:79-88. [DOI: 10.1097/fbp.0000000000000422] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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95
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Taylor NE, Pei J, Zhang J, Vlasov KY, Davis T, Taylor E, Weng FJ, Van Dort CJ, Solt K, Brown EN. The Role of Glutamatergic and Dopaminergic Neurons in the Periaqueductal Gray/Dorsal Raphe: Separating Analgesia and Anxiety. eNeuro 2019; 6:ENEURO.0018-18.2019. [PMID: 31058210 PMCID: PMC6498422 DOI: 10.1523/eneuro.0018-18.2019] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 01/08/2019] [Accepted: 01/29/2019] [Indexed: 12/23/2022] Open
Abstract
The periaqueductal gray (PAG) is a significant modulator of both analgesic and fear behaviors in both humans and rodents, but the underlying circuitry responsible for these two phenotypes is incompletely understood. Importantly, it is not known if there is a way to produce analgesia without anxiety by targeting the PAG, as modulation of glutamate or GABA neurons in this area initiates both antinociceptive and anxiogenic behavior. While dopamine (DA) neurons in the ventrolateral PAG (vlPAG)/dorsal raphe display a supraspinal antinociceptive effect, their influence on anxiety and fear are unknown. Using DAT-cre and Vglut2-cre male mice, we introduced designer receptors exclusively activated by designer drugs (DREADD) to DA and glutamate neurons within the vlPAG using viral-mediated delivery and found that levels of analgesia were significant and quantitatively similar when DA and glutamate neurons were selectively stimulated. Activation of glutamatergic neurons, however, reliably produced higher indices of anxiety, with increased freezing time and more time spent in the safety of a dark enclosure. In contrast, animals in which PAG/dorsal raphe DA neurons were stimulated failed to show fear behaviors. DA-mediated antinociception was inhibitable by haloperidol and was sufficient to prevent persistent inflammatory pain induced by carrageenan. In summary, only activation of DA neurons in the PAG/dorsal raphe produced profound analgesia without signs of anxiety, indicating that PAG/dorsal raphe DA neurons are an important target involved in analgesia that may lead to new treatments for pain.
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Affiliation(s)
| | - JunZhu Pei
- Massachusetts Institute of Technology, Cambridge 02139, MA
| | - Jie Zhang
- University of Utah, Salt Lake City 84112, UT
| | | | | | - Emma Taylor
- University of Massachusetts, Lowell 01854, MA
| | - Feng-Ju Weng
- Massachusetts Institute of Technology, Cambridge 02139, MA
| | | | - Ken Solt
- Massachusetts General Hospital, Boston 02114, MA
| | - Emery N Brown
- Massachusetts General Hospital, Boston 02114, MA
- Massachusetts General Hospital, Boston 02114, MA
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96
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Gao ZR, Chen WZ, Liu MZ, Chen XJ, Wan L, Zhang XY, Yuan L, Lin JK, Wang M, Zhou L, Xu XH, Sun YG. Tac1-Expressing Neurons in the Periaqueductal Gray Facilitate the Itch-Scratching Cycle via Descending Regulation. Neuron 2019; 101:45-59.e9. [DOI: 10.1016/j.neuron.2018.11.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 09/07/2018] [Accepted: 11/05/2018] [Indexed: 02/02/2023]
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97
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Averitt DL, Eidson LN, Doyle HH, Murphy AZ. Neuronal and glial factors contributing to sex differences in opioid modulation of pain. Neuropsychopharmacology 2019; 44:155-165. [PMID: 29973654 PMCID: PMC6235988 DOI: 10.1038/s41386-018-0127-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/21/2018] [Accepted: 05/27/2018] [Indexed: 12/12/2022]
Abstract
Morphine remains one of the most widely prescribed opioids for alleviation of persistent and/or severe pain; however, multiple preclinical and clinical studies report that morphine is less efficacious in females compared to males. Morphine primarily binds to the mu opioid receptor, a prototypical G-protein coupled receptor densely localized in the midbrain periaqueductal gray. Anatomical and physiological studies conducted in the 1960s identified the periaqueductal gray, and its descending projections to the rostral ventromedial medulla and spinal cord, as an essential descending inhibitory circuit mediating opioid-based analgesia. Remarkably, the majority of studies published over the following 30 years were conducted in males with the implicit assumption that the anatomical and physiological characteristics of this descending inhibitory circuit were comparable in females; not surprisingly, this is not the case. Several factors have since been identified as contributing to the dimorphic effects of opioids, including sex differences in the neuroanatomical and neurophysiological characteristics of the descending inhibitory circuit and its modulation by gonadal steroids. Recent data also implicate sex differences in opioid metabolism and neuroimmune signaling as additional contributing factors. Here we cohesively present these lines of evidence demonstrating a neural basis for sex differences in opioid modulation of pain, with a focus on the PAG as a sexually dimorphic core of descending opioid-induced inhibition and argue for the development of sex-specific pain therapeutics.
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Affiliation(s)
- Dayna L Averitt
- Department of Biology, Texas Woman's University, Denton, TX, 76204, USA
| | - Lori N Eidson
- Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Hillary H Doyle
- Neuroscience Institute, Georgia State University, Atlanta, GA, 30303, USA
| | - Anne Z Murphy
- Neuroscience Institute, Georgia State University, Atlanta, GA, 30303, USA.
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98
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Paretkar T, Dimitrov E. Activation of enkephalinergic (Enk) interneurons in the central amygdala (CeA) buffers the behavioral effects of persistent pain. Neurobiol Dis 2018; 124:364-372. [PMID: 30572023 DOI: 10.1016/j.nbd.2018.12.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 10/23/2018] [Accepted: 12/10/2018] [Indexed: 12/25/2022] Open
Abstract
Enk neurons in CeA modulate the activity of the amygdala projection neurons and it is very likely that changes of Enk signaling cause the heightened anxiety that accompanies chronic pain. We use chemogenetics and transgenic mice to investigate the effects of acute and continuous activation of the amygdala Enk neurons on persistent pain and anxiodepressive-like behavior in mice. Enk-cre mice were injected bilaterally into the CeA with cre-activated AAV-DREADD/Gq/mCherry, while neuropathic pain was induced by sciatic nerve constriction. A single injection of DREADD's ligand CNO decreased the anxiety-like behavior in both, uninjured mice and in mice with neuropathic pain and produced robust analgesia that lasted for 24 h. Furthermore, the activation of Enk neurons by the DREADD ligand led to increased c-Fos expression in PKC-δ interneurons of the CeA and in non-serotonergic neurons in the ventrolateral periaqueductal gray (vlPAG), a brain structure that is an essential part of the descending pain inhibitory system. Next, we added CNO to the drinking water of the experimental mice for 14 days in order to assess the effects of continuous activation of CeA Enk interneurons on anxiodepressive-like behavior, which is affected by chronic pain. The prolonged activation of the CeA Enk interneurons reduced neohypophagia in the novelty suppressed feeding test and increased ΔFosB (a marker for sustained neuronal activation) in the vlPAG of mice with chronic pain. All together, the results of our experiments point to an important role of the CeA Enk neurons in the control of both nociception and emotion. Activation of Enk neurons resulted in sustained analgesia accompanied by anxiolysis and antidepressant effects. Very likely, these effects of CeA Enk neurons are result of the activation of vlPAG, a brain region that is essential not only for descending inhibition of pain but it is also a core element in the resilience to stress.
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Affiliation(s)
- Tanvi Paretkar
- Department of Physiology and Biophysics, Chicago Medical School Rosalind Franklin University of Medicine and Science, 3333 Green Bay Rd., North Chicago, IL 60064, United States.
| | - Eugene Dimitrov
- Department of Physiology and Biophysics, Chicago Medical School Rosalind Franklin University of Medicine and Science, 3333 Green Bay Rd., North Chicago, IL 60064, United States.
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99
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Lueptow LM, Fakira AK, Bobeck EN. The Contribution of the Descending Pain Modulatory Pathway in Opioid Tolerance. Front Neurosci 2018; 12:886. [PMID: 30542261 PMCID: PMC6278175 DOI: 10.3389/fnins.2018.00886] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 11/13/2018] [Indexed: 01/20/2023] Open
Abstract
Opioids remain among the most effective pain-relieving therapeutics. However, their long-term use is limited due to the development of tolerance and potential for addiction. For many years, researchers have explored the underlying mechanisms that lead to this decreased effectiveness of opioids after repeated use, and numerous theories have been proposed to explain these changes. The most widely studied theories involve alterations in receptor trafficking and intracellular signaling. Other possible mechanisms include the recruitment of new structural neuronal and microglia networks. While many of these theories have been developed using molecular and cellular techniques, more recent behavioral data also supports these findings. In this review, we focus on the mechanisms that underlie tolerance within the descending pain modulatory pathway, including alterations in intracellular signaling, neural-glial interactions, and neurotransmission following opioid exposure. Developing a better understanding of the relationship between these various mechanisms, within different parts of this pathway, is vital for the identification of more efficacious, novel therapeutics to treat chronic pain.
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Affiliation(s)
- Lindsay M Lueptow
- Department of Psychiatry, Semel Institute for Neuroscience and Human Behavior UCLA, Los Angeles, CA, United States
| | - Amanda K Fakira
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Erin N Bobeck
- Department of Biology, Utah State University, Logan, UT, United States
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100
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韩 曼, 刘 晓, 杜 剑. [Microinjection of endomorphin-1 in the ventrolateral periaqueductal gray induces descending inhibition of cardiac nociception by activating μ-opioid receptor in rats]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2018; 38:1066-1070. [PMID: 30377099 PMCID: PMC6744182 DOI: 10.12122/j.issn.1673-4254.2018.09.07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Indexed: 06/08/2023]
Abstract
OBJECTIVE To observe descending inhibition of cardiac nociception induced by microinjection of endomorphin-1 (EM1) in the ventrolateral periaqueductal gray (VLPAG) in rats effect and explore the role of μ-opioid receptor in mediating this effect. METHODS Male SD rats were randomized into electromyography (EMG) group and c-Fos group, both of which were further divided into 5 subgroups, namely 0.9% NaCl group, bradykinin (BK) group, BK+EM1 group, BK+CTOP group, and BK+CTOP+EM1 group. Rat models of cardiac nociception were established by intrapericardial injection of BK. The changes of cardiaosomatic motor reflex induced by BK were observed by assessing EMG responses of the dorsal spinotrapezius muscle; c-Fos expression in the spinal dorsal horn at levels T3-T5 was tested. RESULTS Compared with 0.9% NaCl, intrapericardial BK injection induced obvious EMG activities and significantly increased c-Fos expression in the spinal dorsal horn at T3-T5 (P < 0.05). Compared with BK injection, microinjection of EM1 in the VLPAG dose-dependently inhibited EMG activities and significantly decreased c-Fos expression (P < 0.05); microinjection of CTOP in the VLPAG produced no significant effect on EMG or c-Fos expression (P > 0.05). Microinjection of CTOP obviously reversed EM1-induced inhibition of EMG activities and c-Fos expression (P < 0.05). CONCLUSIONS Microinjection of EM1 in the VLPAG produces descending inhibition of cardiac nociception in rats by activating μ-opioid receptor.
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Affiliation(s)
- 曼 韩
- 陕西中医药大学生理学教研室,陕西 咸阳 712046Department of Physiology, Shaanxi University of Chinese Medicine, Xianyang 712046, China
| | - 晓华 刘
- 陕西中医药大学生理学教研室,陕西 咸阳 712046Department of Physiology, Shaanxi University of Chinese Medicine, Xianyang 712046, China
| | - 剑青 杜
- 西安交通大学医学部生理学与病理生理学系,陕西 西安 710061Department of Physiology and Pathophysiology, Xi'an Jiaotong University College of Medicine, Xi'an 710061, China
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