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Hu DD, Shi W, Jia X, Shao FM, Zhang L. Alpha-2 receptor mediates the endogenous antagonistic regulation of itch and pain via descending noradrenaline pathway from the locus coeruleus. Brain Res Bull 2025; 223:111270. [PMID: 39999937 DOI: 10.1016/j.brainresbull.2025.111270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2024] [Revised: 02/07/2025] [Accepted: 02/23/2025] [Indexed: 02/27/2025]
Abstract
Pain and itch are sensations that are regulated antagonistically; painful stimulation suppresses itch, while the inhibition of pain enhances itch. However, the central neural circuit underlying this antagonistic regulation remains elusive. The noradrenaline (NA) pathway from the locus coeruleus (LC) to the spinal cord (SC) constitutes an important component of endogenous descending pain inhibitory system. While the pathway of LC:SC has been extensively studied on pain modulation, its role in itch regulation remains poorly understood. We employed behavioral assays for itch and pain, immunofluorescence, electrophysiology, and chemogenetic techniques to investigate the role of noradrenergic (NAergic) neurons of LC (LCNA neurons)and their pathways in modulating itch and pain. Our study has demonstrated that LCNA neurons encode signals for both itch and pain. Inhibition of LCNA neurons had no effect on itch but enhanced pain behaviour. Surprisingly, inhibition of the NAergic projection of LC:SC increased pain and suppressed itch. Furthermore, intrathecal injection of an α2 adrenergic receptor antagonist, but not α1 or β receptor antagonists, produced effects similar to those observed when the LC:SC pathway was inhibited. Our research suggests that the descending NAergic pathway from LC to SC exerts endogenous antagonistic regulation on itch and pain through α2 receptors.
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Affiliation(s)
- Dan-Dan Hu
- Department of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai 201619, China; Clinical Center For Brain And Spinal Cord Research, Tongji University, Shanghai 200331, China
| | - Wu Shi
- Department of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai 201619, China; Clinical Center For Brain And Spinal Cord Research, Tongji University, Shanghai 200331, China
| | - Xin Jia
- Department of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai 201619, China; Clinical Center For Brain And Spinal Cord Research, Tongji University, Shanghai 200331, China
| | - Fu-Ming Shao
- Department of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai 201619, China; Clinical Center For Brain And Spinal Cord Research, Tongji University, Shanghai 200331, China
| | - Ling Zhang
- Department of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai 201619, China; Clinical Center For Brain And Spinal Cord Research, Tongji University, Shanghai 200331, China.
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2
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Huang SS. Challenges in the management of visual and tactile hallucinations in elderly people. World J Psychiatry 2025; 15:101946. [PMID: 39831009 PMCID: PMC11684211 DOI: 10.5498/wjp.v15.i1.101946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2024] [Revised: 11/03/2024] [Accepted: 12/06/2024] [Indexed: 12/18/2024] Open
Abstract
This letter provides a concise review of the pertinent literature on visual and tactile hallucinations in elderly patients. The discussion addresses differential diagnoses and potential underlying mechanisms, as well as the psychopathology associated with tactile hallucinations, and emphasizes the necessity for investigation into the possibility of coexisting delusional infestation (parasitosis). These symptoms frequently manifest in patients with primary psychotic disorders, organic mental disorders, and substance use disorders. The proposed pathophysiological mechanisms may involve dopaminergic imbalances and dysfunction of the striatal dopamine transporter.
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Affiliation(s)
- Si-Sheng Huang
- Division of Geriatric Psychiatry, Department of Psychiatry, Changhua Christian Hospital, Changhua 500, Taiwan
- Department of Post-Baccalaureate Medicine, College of Medicine, National Chung Hsing University, Taichung 402, Taiwan
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3
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Song W, Zhou ZM, Zhang LL, Shu HF, Xia JR, Qin X, Hua R, Zhang YM. Infiltrating peripheral monocyte TREM-1 mediates dopaminergic neuron injury in substantia nigra of Parkinson's disease model mice. Cell Death Dis 2025; 16:18. [PMID: 39809747 PMCID: PMC11733277 DOI: 10.1038/s41419-025-07333-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 11/20/2024] [Accepted: 01/07/2025] [Indexed: 01/16/2025]
Abstract
Neuroinflammation is a key factor in the pathogenesis of Parkinson's disease (PD). Activated microglia in the central nervous system (CNS) and infiltration of peripheral immune cells contribute to dopaminergic neuron loss. However, the role of peripheral immune responses, particularly triggering receptor expressed on myeloid cells-1 (TREM-1), in PD remains unclear. Using a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP)-induced PD mouse model, we examined TREM-1 expression and monocyte infiltration in the substantia nigra pars compacta (SNpc). We found that MPTP increased peripheral monocytes, and deletion of peripheral monocytes protected against MPTP neurotoxicity in the SNpc. TREM-1 inhibition, both genetically and pharmacologically, reduced monocyte infiltration, alleviated neuroinflammation, and preserved dopaminergic neurons, resulting in improved motor function. Furthermore, adoptive transfer of TREM-1-expressing monocytes from PD model mice to naive mice induced neuronal damage and motor deficits. These results underscore the critical role of peripheral monocytes and TREM-1 in PD progression, suggesting that targeting TREM-1 could be a promising therapeutic approach to prevent dopaminergic neurodegeneration and motor dysfunction in PD. Schematic diagram of monocyte TREM-1-mediated dopaminergic neuron damage. The figure illustrates that in experimental MPTP-induced PD model mice, the number of inflammatory monocytes in the peripheral blood increases, after which the monocytes infiltrate the CNS through the Blood-Brain Barrier(BBB). These infiltrating monocytes increase the release of inflammatory cytokines and eventually cause neuronal injury. TREM-1 gene deletion and pharmacological blockade limit inflammatory monocyte recruitment into the SNpc and ameliorate neuroinflammatory events and the loss of dopaminergic neurons.
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Affiliation(s)
- Wei Song
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou, China
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China
- Yancheng Stomatological Hospital, Yancheng, China
| | - Zi-Ming Zhou
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou, China
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China
| | - Le-le Zhang
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou, China
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China
| | - Hai-Feng Shu
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou, China
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China
| | - Jin-Ru Xia
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou, China
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China
| | - Xia Qin
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou, China
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China
| | - Rong Hua
- Department of Emergency, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China.
| | - Yong-Mei Zhang
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Xuzhou, China.
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China.
- Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China.
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4
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Leibovit-Reiben Z, Godfrey H, Stanley A, Thiede R. More than just dermatitis: The multifaceted nature of chronic itch through the historical perspective of Napoleon Bonaparte. Clin Dermatol 2024; 42:709-714. [PMID: 38944246 DOI: 10.1016/j.clindermatol.2024.06.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2024]
Abstract
Derived from the survival advantage needed to eradicate harmful irritants from the skin's surface, itch, also known as pruritus, is an intriguing phenomenon and a key feature of many dermatologic diseases. The pathologic form, chronic itch, is a condition that precedes itself by its complex pathophysiology, numerous etiologies, and interplay of mechanisms that often make it difficult to diagnose and treat. One particular sufferer of this condition, the 18th-century French emperor Napoleon Bonaparte, makes for a compelling case study of the complexity of chronic itch. We delve into the many etiologies and mechanisms of chronic itch, using Napoleon's lifelong struggle with this condition as our model, identifying potential environmental, neurologic, psychiatric, and immunologic origins of his condition.
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Affiliation(s)
| | - Hannah Godfrey
- University of Arizona College of Medicine-Tucson, Tucson, Arizona, USA
| | - Alissa Stanley
- University of Arizona College of Medicine-Tucson, Tucson, Arizona, USA
| | - Rebecca Thiede
- Division of Dermatology, University of Arizona College of Medicine-Tucson, Tucson, Arizona, USA
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5
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Li J, Bai Y, Ge J, Zhang Y, Zhao Q, Li D, Guo B, Gao S, Zhu Y, Cai G, Wan X, Huang J, Wu S. Cell Type-Specific Modulation of Acute Itch Processing in the Anterior Cingulate Cortex. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2403445. [PMID: 39316379 DOI: 10.1002/advs.202403445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 07/24/2024] [Indexed: 09/25/2024]
Abstract
Despite remarkable progress in understanding the fundamental bases of itching, its cortical mechanisms remain poorly understood. Herein, the causal contributions of defined anterior cingulate cortex (ACC) neuronal populations to acute itch modulation in mice are established. Using cell type-specific manipulations, the opposing functions of ACC glutamatergic and GABAergic neurons in regulating acute itching are demonstrated. Photometry studies indicated that ACC glutamatergic neurons are activated during scratching induced by both histamine and chloroquine, whereas the activation pattern of GABAergic neurons is complicated by GABAergic subpopulations and acute itch modalities. By combining cell type- and projection-specific techniques, a thalamocortical circuit is further identified from the mediodorsal thalamus driving the itch-scratching cycle related to histaminergic and non-histaminergic itching, which is contingent on the activation of postsynaptic parvalbumin-expressing neurons in the ACC. These findings reveal a cellular and circuit signature of ACC neurons orchestrating behavioral responses to itching and may provide insights into therapies for itch-related diseases.
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Affiliation(s)
- Jiaqi Li
- Department of Neurobiology, Basic Medical Science Academy, Fourth Military Medical University, Xi'an, 710032, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Yang Bai
- Department of Neurosurgery, General Hospital of Northern Theater Command, Shenyang, 110015, China
| | - Junye Ge
- Department of Neurobiology, Basic Medical Science Academy, Fourth Military Medical University, Xi'an, 710032, China
| | - Yiwen Zhang
- Department of Neurobiology, Basic Medical Science Academy, Fourth Military Medical University, Xi'an, 710032, China
| | - Qiuying Zhao
- Department of Neurobiology, Basic Medical Science Academy, Fourth Military Medical University, Xi'an, 710032, China
| | - Dangchao Li
- Department of Neurobiology, Basic Medical Science Academy, Fourth Military Medical University, Xi'an, 710032, China
| | - Baolin Guo
- Department of Neurobiology, Basic Medical Science Academy, Fourth Military Medical University, Xi'an, 710032, China
| | - Shasha Gao
- Department of Neurobiology, Basic Medical Science Academy, Fourth Military Medical University, Xi'an, 710032, China
| | - Yuanyuan Zhu
- Department of Neurobiology, Basic Medical Science Academy, Fourth Military Medical University, Xi'an, 710032, China
| | - Guohong Cai
- Department of Neurobiology, Basic Medical Science Academy, Fourth Military Medical University, Xi'an, 710032, China
| | - Xiangdong Wan
- Department of Neurobiology, Basic Medical Science Academy, Fourth Military Medical University, Xi'an, 710032, China
| | - Jing Huang
- Department of Neurobiology, Basic Medical Science Academy, Fourth Military Medical University, Xi'an, 710032, China
| | - Shengxi Wu
- Department of Neurobiology, Basic Medical Science Academy, Fourth Military Medical University, Xi'an, 710032, China
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Xu JF, Liu L, Liu Y, Lu KX, Zhang J, Zhu YJ, Fang F, Dou YN. Spinal Nmur2-positive Neurons Play a Crucial Role in Mechanical Itch. THE JOURNAL OF PAIN 2024; 25:104504. [PMID: 38442838 DOI: 10.1016/j.jpain.2024.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 02/23/2024] [Accepted: 02/29/2024] [Indexed: 03/07/2024]
Abstract
The dorsal spinal cord is crucial for the transmission and modulation of multiple somatosensory modalities, such as itch, pain, and touch. Despite being essential for the well-being and survival of an individual, itch and pain, in their chronic forms, have increasingly been recognized as clinical problems. Although considerable progress has been made in our understanding of the neurochemical processing of nociceptive and chemical itch sensations, the neural substrate that is crucial for mechanical itch processing is still unclear. Here, using genetic and functional manipulation, we identified a population of spinal neurons expressing neuromedin U receptor 2 (Nmur2+) as critical elements for mechanical itch. We found that spinal Nmur2+ neurons are predominantly excitatory neurons, and are enriched in the superficial laminae of the dorsal horn. Pharmacogenetic activation of cervical spinal Nmur2+ neurons evoked scratching behavior. Conversely, the ablation of these neurons using a caspase-3-based method decreased von Frey filament-induced scratching behavior without affecting responses to other somatosensory modalities. Similarly, suppressing the excitability of cervical spinal Nmur2+ neurons via the overexpression of functional Kir2.1 potassium channels reduced scratching in response to innocuous mechanical stimuli, but not to pruritogen application. At the lumbar level, pharmacogenetic activation of these neurons evoked licking and lifting behaviors. However, ablating these neurons did not affect the behavior associated with acute pain. Thus, these results revealed the crucial role of spinal Nmur2+ neurons in mechanical itch. Our study provides important insights into the neural basis of mechanical itch, paving the way for developing novel therapies for chronic itch. PERSPECTIVE: Excitatory Nmur2+ neurons in the superficial dorsal spinal cord are essential for mechanical but not chemical itch information processing. These spinal Nmur2+ neurons represent a potential cellular target for future therapeutic interventions against chronic itch. Spinal and supraspinal Nmur2+ neurons may play different roles in pain signal processing.
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Affiliation(s)
- Jun-Feng Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Lian Liu
- Department of Endocrinology and Metabolic Diseases, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yuan Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China; School of Life Science and Technology, ShanghaiTech University, Shanghai, China; Lingang Laboratory, Shanghai, China
| | - Ke-Xing Lu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Jun Zhang
- Department of Anesthesiology, Daping Hospital, Army Medical University, Chongqing, China
| | - Yan-Jing Zhu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Fang Fang
- Department of Endocrinology and Metabolic Diseases, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yan-Nong Dou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
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7
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Long JH, Wang PJ, Xuan L, Juan Y, Wu GY, Teng JF, Sui JF, Li YM, Yang L, Li HL, Liu SL. Prelimbic cortex-nucleus accumbens core projection positively regulates itch and itch-related aversion. Behav Brain Res 2024; 468:114999. [PMID: 38615978 DOI: 10.1016/j.bbr.2024.114999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 04/08/2024] [Accepted: 04/11/2024] [Indexed: 04/16/2024]
Abstract
Itch is one of the most common clinical symptoms in patients with diseases of the skin, liver, or kidney, and it strongly triggers aversive emotion and scratching behavior. Previous studies have confirmed the role of the prelimbic cortex (Prl) and the nucleus accumbens core (NAcC), which are reward and motivation regulatory centers, in the regulation of itch. However, it is currently unclear whether the Prl-NAcC projection, an important pathway connecting these two brain regions, is involved in the regulation of itch and its associated negative emotions. In this study, rat models of acute neck and cheek itch were established by subcutaneous injection of 5-HT, compound 48/80, or chloroquine. Immunofluorescence experiments determined that the number of c-Fos-immunopositive neurons in the Prl increased during acute itch. Chemogenetic inhibition of Prl glutamatergic neurons or Prl-NAcC glutamatergic projections can inhibit both histaminergic and nonhistaminergic itch-scratching behaviors and rectify the itch-related conditioned place aversion (CPA) behavior associated with nonhistaminergic itch. The Prl-NAcC projection may play an important role in the positive regulation of itch-scratching behavior by mediating the negative emotions related to itch.
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Affiliation(s)
- Jun-Hui Long
- Southwest Hospital Jiangbei Area (The 958th hospital of Chinese People's Liberation Army), Chongqing, China
| | - Pu-Jun Wang
- Southwest Hospital Jiangbei Area (The 958th hospital of Chinese People's Liberation Army), Chongqing, China
| | - Li Xuan
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Yao Juan
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Guang-Yan Wu
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Jun-Fei Teng
- Southwest Hospital Jiangbei Area (The 958th hospital of Chinese People's Liberation Army), Chongqing, China
| | - Jian-Feng Sui
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Ya-Min Li
- Institute of Economics and Business Management, Chongqing University of Education, Chongqing, China
| | - Liu Yang
- Southwest Hospital Jiangbei Area (The 958th hospital of Chinese People's Liberation Army), Chongqing, China
| | - Hong-Li Li
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China.
| | - Shu-Lei Liu
- Southwest Hospital Jiangbei Area (The 958th hospital of Chinese People's Liberation Army), Chongqing, China.
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Inokuchi-Sakata S, Narita R, Takahashi Y, Ishiuji Y, Asahina A, Kato F. Region-specific activation in the accumbens nucleus by itch with modified scratch efficacy in mice - a model-free multivariate analysis. Mol Brain 2024; 17:27. [PMID: 38783364 PMCID: PMC11119306 DOI: 10.1186/s13041-024-01101-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 05/15/2024] [Indexed: 05/25/2024] Open
Abstract
Itch is a protective/defensive function with divalent motivational drives. Itch itself elicits an unpleasant experience, which triggers the urge to scratch, relieving the itchiness. Still, it can also result in dissatisfaction when the scratch is too intense and painful or unsatisfactory due to insufficient scratch effect. Therefore, it is likely that the balance between the unpleasantness/pleasure and satisfaction/unsatisfaction associated with itch sensation and scratching behavior is determined by complex brain mechanisms. The physiological/pathological mechanisms underlying this balance remain largely elusive. To address this issue, we targeted the "reward center" of the brain, the nucleus accumbens (NAc), in which itch-responsive neurons have been found in rodents. We examined how neurons in the NAc are activated or suppressed during histamine-induced scratching behaviors in mice. The mice received an intradermal injection of histamine or saline at the neck, and the scratching number was analyzed by recording the movement of the bilateral hind limbs for about 45 min after injection. To experimentally manipulate the scratch efficacy in these histamine models, we compared histamine's behavioral and neuronal effects between mice with intact and clipped nails on the hind paws. As expected, the clipping of the hind limb nail increased the number of scratches after the histamine injection. In the brains of mice exhibiting scratching behaviors, we analyzed the expression of the c-fos gene (Fos) as a readout of an immediate activation of neurons during itch/scratch and dopamine receptors (Drd1 and Drd2) using multiplex single-molecule fluorescence in situ hybridization (RNAscope) in the NAc and surrounding structures. We performed a model-free analysis of gene expression in geometrically divided NAc subregions without assuming the conventional core-shell divisions. The results indicated that even within the NAc, multiple subregions responded differentially to various itch/scratch conditions. We also found different clusters with neurons showing similar or opposite changes in Fos expression and the correlation between scratch number and Fos expression in different itch/scratch conditions. These regional differences and clusters would provide a basis for the complex role of the NAc and surrounding structures in encoding the outcomes of scratching behavior and itchy sensations.
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Affiliation(s)
- Sanae Inokuchi-Sakata
- Department of Dermatology, The Jikei University School of Medicine, Minato-Ku, Tokyo, 105-8461, Japan
- Department of Neuroscience, The Jikei University School of Medicine, Minato-ku, Tokyo, 105-8461, Japan
| | - Ryo Narita
- Department of Neuroscience, The Jikei University School of Medicine, Minato-ku, Tokyo, 105-8461, Japan
- Center for Neuroscience of Pain, The Jikei University School of Medicine, Minato-Ku, Tokyo, 105-8461, Japan
| | - Yukari Takahashi
- Department of Neuroscience, The Jikei University School of Medicine, Minato-ku, Tokyo, 105-8461, Japan
- Center for Neuroscience of Pain, The Jikei University School of Medicine, Minato-Ku, Tokyo, 105-8461, Japan
| | - Yozo Ishiuji
- Department of Dermatology, The Jikei University School of Medicine, Minato-Ku, Tokyo, 105-8461, Japan
- Center for Neuroscience of Pain, The Jikei University School of Medicine, Minato-Ku, Tokyo, 105-8461, Japan
| | - Akihiko Asahina
- Department of Dermatology, The Jikei University School of Medicine, Minato-Ku, Tokyo, 105-8461, Japan
| | - Fusao Kato
- Department of Neuroscience, The Jikei University School of Medicine, Minato-ku, Tokyo, 105-8461, Japan.
- Center for Neuroscience of Pain, The Jikei University School of Medicine, Minato-Ku, Tokyo, 105-8461, Japan.
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9
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Zheng J, Zhang XM, Tang W, Li Y, Wang P, Jin J, Luo Z, Fang S, Yang S, Wei Z, Song K, Huang Z, Wang Z, Zhu Z, Shi N, Xiao D, Yuan L, Shen H, Huang L, Li B. An insular cortical circuit required for itch sensation and aversion. Curr Biol 2024; 34:1453-1468.e6. [PMID: 38484733 DOI: 10.1016/j.cub.2024.02.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 01/09/2024] [Accepted: 02/23/2024] [Indexed: 04/11/2024]
Abstract
Itch encompasses both sensory and emotional dimensions, with the two dimensions reciprocally exacerbating each other. However, whether a shared neural circuit mechanism governs both dimensions remains elusive. Here, we report that the anterior insular cortex (AIC) is activated by both histamine-dependent and -independent itch stimuli. The activation of AIC elicits aversive emotion and exacerbates pruritogen-induced itch sensation and aversion. Mechanistically, AIC excitatory neurons project to the GABAergic neurons in the dorsal bed nucleus of the stria terminalis (dBNST). Manipulating the activity of the AIC → dBNST pathway affects both itch sensation and itch-induced aversion. Our study discovers the shared neural circuit (AIC → dBNST pathway) underlying the itch sensation and aversion, highlights the critical role of the AIC as a central hub for the itch processing, and provides a framework to understand the neural mechanisms underlying the sensation and emotion interaction.
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Affiliation(s)
- Jieyan Zheng
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Advanced Medical Technology Center, the First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Xiao Min Zhang
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Advanced Medical Technology Center, the First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Wenting Tang
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Advanced Medical Technology Center, the First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Yonglin Li
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Advanced Medical Technology Center, the First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Pei Wang
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Advanced Medical Technology Center, the First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Jianhua Jin
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Advanced Medical Technology Center, the First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Zhengyi Luo
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Advanced Medical Technology Center, the First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Shunchang Fang
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Advanced Medical Technology Center, the First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Shana Yang
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Advanced Medical Technology Center, the First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Zicheng Wei
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Advanced Medical Technology Center, the First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Kexin Song
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Zihan Huang
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Zihao Wang
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Ziyu Zhu
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Naizhen Shi
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Diyun Xiao
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Linyu Yuan
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Hualin Shen
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Lianyan Huang
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory of Human Microbiome and Chronic Diseases (Sun Yat-sen University), Ministry of Education, Guangzhou 510655, China.
| | - Boxing Li
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Advanced Medical Technology Center, the First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Key Laboratory of Human Microbiome and Chronic Diseases (Sun Yat-sen University), Ministry of Education, Guangzhou 510655, China.
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10
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Mindru FM, Radu AF, Bumbu AG, Radu A, Bungau SG. Insights into the Medical Evaluation of Ekbom Syndrome: An Overview. Int J Mol Sci 2024; 25:2151. [PMID: 38396826 PMCID: PMC10889746 DOI: 10.3390/ijms25042151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 01/30/2024] [Accepted: 02/08/2024] [Indexed: 02/25/2024] Open
Abstract
Ekbom syndrome, also known as delusional parasitosis (DP) or delusional infestation, is an uncommon psychiatric disorder distinguished by an enduring conviction of parasitic infestation, persisting notwithstanding the presence of medical evidence to the contrary. Primarily affecting middle-aged women, DP can manifest either as isolated psychological distress or as a component within a more intricate psychiatric framework, substantially influencing the quality of life for affected individuals. Its pathophysiological mechanism involves uncertain dopaminergic imbalances and dysfunction in the dopamine transporter system. Dermatologists often play a pivotal role in diagnosis, as patients first seek dermatological assessments of their signs and symptoms. However, DP frequently originates from underlying psychiatric disorders or medical variables, manifesting with neurological and infectious causative factors. The diagnostic complexity is attributed to patients' resolute convictions, leading to delayed psychiatric intervention. First-line DP treatment involves antipsychotics, with newer agents demonstrating promising prospects, but the lack of standardized protocols poses a significant therapeutic challenge. In this narrative review, both a comprehensive approach to this uncommon pathology and an update on the state of knowledge in this medical subfield focused on optimizing the management of DP are provided. The complexity of DP underlying its uncommon nature and the incomplete understanding of its pathophysiology highlight the need for further research through multicenter studies and multidisciplinary teams to enhance therapeutic efficacy and safety.
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Affiliation(s)
- Florina Madalina Mindru
- Doctoral School of Biomedical Sciences, University of Oradea, 410087 Oradea, Romania; (F.M.M.); (A.R.); (S.G.B.)
| | - Andrei-Flavius Radu
- Doctoral School of Biomedical Sciences, University of Oradea, 410087 Oradea, Romania; (F.M.M.); (A.R.); (S.G.B.)
- Department of Preclinical Disciplines, Faculty of Medicine and Pharmacy, University of Oradea, 410073 Oradea, Romania
| | - Adrian Gheorghe Bumbu
- Doctoral School of Biomedical Sciences, University of Oradea, 410087 Oradea, Romania; (F.M.M.); (A.R.); (S.G.B.)
- Department of Psycho-Neuroscience and Recovery, Faculty of Medicine and Pharmacy, University of Oradea, 410073 Oradea, Romania
| | - Ada Radu
- Doctoral School of Biomedical Sciences, University of Oradea, 410087 Oradea, Romania; (F.M.M.); (A.R.); (S.G.B.)
| | - Simona Gabriela Bungau
- Doctoral School of Biomedical Sciences, University of Oradea, 410087 Oradea, Romania; (F.M.M.); (A.R.); (S.G.B.)
- Department of Pharmacy, Faculty of Medicine and Pharmacy, University of Oradea, 410028 Oradea, Romania
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11
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Prajapati JN, Reddy P, Barik A. Neural pathways that compel us to scratch an itch. J Biosci 2024; 49:70. [PMID: 38973668 PMCID: PMC7617712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2024]
Abstract
Itch is a unique sensory experience that is responded to by scratching. How pruritogens, which are mechanical and chemical stimuli with the potential to cause itch, engage specific pathways in the peripheral and central nervous system has been a topic of intense investigation over the last few years. Studies employing recently developed molecular, physiological, and behavioral techniques have delineated the dedicated mechanisms that transmit itch information to the brain. This review outlines the genetically defined and evolutionary conserved circuits for itch ranging from the skin-innervating peripheral neurons to the cortical neurons that drive scratching. Moreover, scratch suppression of itch is attributed to the concurrent activation of pain and itch pathways. Hence, we discuss the similarities between circuits driving pain and itch.
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Affiliation(s)
| | - Prannay Reddy
- Center for Neuroscience, Indian Institute of Science, Bengaluru560012, India
| | - Arnab Barik
- Center for Neuroscience, Indian Institute of Science, Bengaluru560012, India
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12
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Yao J, Li X, Wu GY, Wu B, Long JH, Wang PJ, Liu SL, Gao J, Sui JF. The Anterior Insula and its Projection to the Prelimbic Cortex are Involved in the Regulation of 5-HT-Induced Itch. Neurosci Bull 2023; 39:1807-1822. [PMID: 37553505 PMCID: PMC10661608 DOI: 10.1007/s12264-023-01093-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 04/12/2023] [Indexed: 08/10/2023] Open
Abstract
Itch is an unpleasant sensation that urges people and animals to scratch. Neuroimaging studies on itch have yielded extensive correlations with diverse cortical and subcortical regions, including the insular lobe. However, the role and functional specificity of the insular cortex (IC) and its subdivisions in itch mediation remains unclear. Here, we demonstrated by immunohistochemistry and fiber photometry tests, that neurons in both the anterior insular cortex (AIC) and the posterior insular cortex (PIC) are activated during acute itch processes. Pharmacogenetic experiments revealed that nonselective inhibition of global AIC neurons, or selective inhibition of the activity of glutaminergic neurons in the AIC, reduced the scratching behaviors induced by intradermal injection of 5-hydroxytryptamine (5-HT), but not those induced by compound 48/80. However, both nonselective inhibition of global PIC neurons and selective inhibition of glutaminergic neurons in the PIC failed to affect the itching-scratching behaviors induced by either 5-HT or compound 48/80. In addition, pharmacogenetic inhibition of AIC glutaminergic neurons effectively blocked itch-associated conditioned place aversion behavior, and inhibition of AIC glutaminergic neurons projecting to the prelimbic cortex significantly suppressed 5-HT-evoked scratching. These findings provide preliminary evidence that the AIC is involved, at least partially via aversive emotion mediation, in the regulation of 5-HT-, but not compound 48/80-induced itch.
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Affiliation(s)
- Juan Yao
- Experimental Center of Basic Medicine, Army Medical University, Chongqing, 400038, China
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing, 400038, China
| | - Xuan Li
- Experimental Center of Basic Medicine, Army Medical University, Chongqing, 400038, China
| | - Guang-Yan Wu
- Experimental Center of Basic Medicine, Army Medical University, Chongqing, 400038, China
| | - Bing Wu
- Experimental Center of Basic Medicine, Army Medical University, Chongqing, 400038, China
| | - Jun-Hui Long
- Department of Dermatology, The 958th Army Hospital of the People's Liberation Army, Chongqing, 400020, China
| | - Pu-Jun Wang
- Department of Dermatology, The 958th Army Hospital of the People's Liberation Army, Chongqing, 400020, China
| | - Shu-Lei Liu
- Department of Dermatology, The 958th Army Hospital of the People's Liberation Army, Chongqing, 400020, China
| | - Jie Gao
- State Key Laboratory of Trauma, Burns and Combined Injury, Army Medical Centre of the PLA, Institute of Surgery Research, Daping Hospital, Army Medical University, Chongqing, 400042, China.
| | - Jian-Feng Sui
- Experimental Center of Basic Medicine, Army Medical University, Chongqing, 400038, China.
- Department of Physiology, College of Basic Medical Sciences, Army Medical University, Chongqing, 400038, China.
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13
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Chen WZ, Shen TY, Wang M, Yuan L, Wang LH, Ding WQ, Shi XX, Wang XF, Bo BS, Liang ZF, Sun YG. An atlas of itch-associated neural dynamics in the mouse brain. Cell Rep 2023; 42:113304. [PMID: 37862165 DOI: 10.1016/j.celrep.2023.113304] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 08/07/2023] [Accepted: 10/04/2023] [Indexed: 10/22/2023] Open
Abstract
The itch-scratching cycle is mediated by neural dynamics in the brain. However, our understanding of the neural dynamics during this cycle remains limited. In this study, we examine the neural dynamics of 126 mouse brain areas by measuring the calcium signal using fiber photometry. We present numerous response patterns in the mouse brain during the itch-scratching cycle. Interestingly, we find that a group of brain areas exhibit activation only at the end of histamine-induced scratching behavior. Additionally, several brain areas exhibit transient activation at the onset of scratching induced by chloroquine. Both histamine- and chloroquine-induced itch evoke diverse response patterns across the mouse brain. In summary, our study provides a comprehensive dataset for the diverse activity pattern of mouse brain during the itch-scratching cycle, paving the way for further exploration into the neural mechanisms underlying the itch-scratching cycle.
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Affiliation(s)
- Wen-Zhen 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, Shanghai 200031, China; University of Chinese Academy of Sciences, 19A Yu-quan Road, Beijing 100049, China
| | - Ting-Yu Shen
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China; University of Chinese Academy of Sciences, 19A Yu-quan Road, Beijing 100049, China
| | - Meng Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China; University of Chinese Academy of Sciences, 19A Yu-quan Road, Beijing 100049, China
| | - Lin Yuan
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China; Department of Orthopaedic Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Lin-Han Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China; University of Chinese Academy of Sciences, 19A Yu-quan Road, Beijing 100049, China
| | - Wen-Qun Ding
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China; University of Chinese Academy of Sciences, 19A Yu-quan Road, Beijing 100049, China
| | - Xiao-Xue Shi
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Xiao-Fei Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Bin-Shi Bo
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Zhi-Feng Liang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, 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, Shanghai 200031, China.
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14
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Zhang Z, Shao H, Liu C, Song H, Wu X, Cao D, Zhu M, Fu Y, Wang J, Gao Y. Descending dopaminergic pathway facilitates itch signal processing via activating spinal GRPR + neurons. EMBO Rep 2023; 24:e56098. [PMID: 37522391 PMCID: PMC10561366 DOI: 10.15252/embr.202256098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 07/10/2023] [Accepted: 07/14/2023] [Indexed: 08/01/2023] Open
Abstract
A11 dopaminergic neurons regulate somatosensory transduction by projecting from the diencephalon to the spinal cord, but the function of this descending projection in itch remained elusive. Here, we report that dopaminergic projection neurons from the A11 nucleus to the spinal dorsal horn (dopaminergicA11-SDH ) are activated by pruritogens. Inhibition of these neurons alleviates itch-induced scratching behaviors. Furthermore, chemogenetic inhibition of spinal dopamine receptor D1-expressing (DRD1+ ) neurons decreases acute or chronic itch-induced scratching. Mechanistically, spinal DRD1+ neurons are excitatory and mostly co-localize with gastrin-releasing peptide (GRP), an endogenous neuropeptide for itch. In addition, DRD1+ neurons form synapses with GRP receptor-expressing (GRPR+ ) neurons and activate these neurons via AMPA receptor (AMPAR). Finally, spontaneous itch and enhanced acute itch induced by activating spinal DRD1+ neurons are relieved by antagonists against AMPAR and GRPR. Thus, the descending dopaminergic pathway facilitates spinal itch transmission via activating DRD1+ neurons and releasing glutamate and GRP, which directly augments GRPR signaling. Interruption of this descending pathway may be used to treat chronic itch.
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Affiliation(s)
- Zhi‐Jun Zhang
- Institute of Pain Medicine and Special Environmental Medicine, Co‐Innovation Center of NeuroregenerationNantong UniversityJiangsuChina
- Department of Human Anatomy, School of MedicineNantong UniversityJiangsuChina
| | - Han‐Yu Shao
- Department of Human Anatomy, School of MedicineNantong UniversityJiangsuChina
| | - Chuan Liu
- Department of Human Anatomy, School of MedicineNantong UniversityJiangsuChina
| | - Hao‐Lin Song
- Department of Human Anatomy, School of MedicineNantong UniversityJiangsuChina
| | - Xiao‐Bo Wu
- Institute of Pain Medicine and Special Environmental Medicine, Co‐Innovation Center of NeuroregenerationNantong UniversityJiangsuChina
| | - De‐Li Cao
- Institute of Pain Medicine and Special Environmental Medicine, Co‐Innovation Center of NeuroregenerationNantong UniversityJiangsuChina
| | - Meixuan Zhu
- University of North Carolina at Chapel HillChapel HillNCUSA
| | - Yuan‐Yuan Fu
- Institute of Pain Medicine and Special Environmental Medicine, Co‐Innovation Center of NeuroregenerationNantong UniversityJiangsuChina
| | - Juan Wang
- Department of Human Anatomy, School of MedicineNantong UniversityJiangsuChina
| | - Yong‐Jing Gao
- Institute of Pain Medicine and Special Environmental Medicine, Co‐Innovation Center of NeuroregenerationNantong UniversityJiangsuChina
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15
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Chen R, Xu X, Wang XY, Jia WB, Zhao DS, Liu N, Pang Z, Liu XQ, Zhang Y. The lateral habenula nucleus regulates pruritic sensation and emotion. Mol Brain 2023; 16:54. [PMID: 37370111 DOI: 10.1186/s13041-023-01045-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023] Open
Abstract
Itch is a complex aversive sensory and emotional experience. As a most upsetting symptom in many dermatological and systemic diseases, it lacks efficient treatments. The lateral habenula nucleus (LHb) encodes negative emotions in the epithalamus and has been implicated in pain and analgesia. Nevertheless, the role of the lateral habenula nucleus in the pruritic sensation and emotion remains elusive. Here we defined the crucial role of glutamatergic neurons within the lateral habenula nucleus (GluLHb) in itch modulation in mice. We established histamine-dependent and histamine-independent models of acute pruritus, as well as the acetone-ether-water (AEW) model of chronic pruritus. We first assessed the effects of pruritogen injection on neural activation in both medial and lateral divisions of LHb in vitro. We then demonstrated that the population activity of GluLHb neurons was increased during the acute itch and chronic itch-induced scratching behaviors in vivo. In addition, electrophysiological data showed that the excitability of GluLHb neurons was enhanced by chronic itch. Chemogenetic suppression of GluLHb neurons disrupted both acute and chronic itch-evoked scratching behaviors. Furthermore, itch-induced conditioned place aversion (CPA) was abolished by GluLHb neuronal inhibition. Finally, we dissected the LHb upstream brain regions. Together, these findings reveal the involvement of LHb in processing both the sensational and emotional components of pruritus and may shed new insights into itch therapy.
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Affiliation(s)
- Rui Chen
- Department of Neurology, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Xiang Xu
- Department of Neurology, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Xin-Yue Wang
- Department of Neurology, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Wen-Bin Jia
- Department of Neurology, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - De-Shan Zhao
- School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Na Liu
- School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Zhen Pang
- School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Xiao-Qing Liu
- School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Yan Zhang
- Department of Neurology, Division of Life Sciences and Medicine, The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, Anhui, 230001, China.
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16
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Li JN, Wu XM, Zhao LJ, Sun HX, Hong J, Wu FL, Chen SH, Chen T, Li H, Dong YL, Li YQ. Central medial thalamic nucleus dynamically participates in acute itch sensation and chronic itch-induced anxiety-like behavior in male mice. Nat Commun 2023; 14:2539. [PMID: 37137899 PMCID: PMC10156671 DOI: 10.1038/s41467-023-38264-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 04/20/2023] [Indexed: 05/05/2023] Open
Abstract
Itch is an annoying sensation consisting of both sensory and emotional components. It is known to involve the parabrachial nucleus (PBN), but the following transmission nodes remain elusive. The present study identified that the PBN-central medial thalamic nucleus (CM)-medial prefrontal cortex (mPFC) pathway is essential for itch signal transmission at the supraspinal level in male mice. Chemogenetic inhibition of the CM-mPFC pathway attenuates scratching behavior or chronic itch-related affective responses. CM input to mPFC pyramidal neurons is enhanced in acute and chronic itch models. Specifically chronic itch stimuli also alter mPFC interneuron involvement, resulting in enhanced feedforward inhibition and a distorted excitatory/inhibitory balance in mPFC pyramidal neurons. The present work underscores CM as a transmit node of the itch signal in the thalamus, which is dynamically engaged in both the sensory and affective dimensions of itch with different stimulus salience.
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Affiliation(s)
- Jia-Ni Li
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
| | - Xue-Mei Wu
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
- Department of Human Anatomy, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Liu-Jie Zhao
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
- Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, 450001, China
| | - Han-Xue Sun
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
- Department of Human Anatomy, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, China
| | - Jie Hong
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
- Department of Human Anatomy, Baotou Medical College Inner Mongolia University of Science and Technology, Baotou, 014040, China
| | - Feng-Ling Wu
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
- Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, 450001, China
| | - Si-Hai Chen
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
- Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, 450001, China
| | - Tao Chen
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
| | - Hui Li
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China
| | - Yu-Lin Dong
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China.
| | - Yun-Qing Li
- Department of Anatomy, Histology and Embryology, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, 710032, China.
- Department of Human Anatomy, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, 610041, China.
- Department of Anatomy, Basic Medical College, Zhengzhou University, Zhengzhou, 450001, China.
- Department of Human Anatomy, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, China.
- Department of Human Anatomy, Baotou Medical College Inner Mongolia University of Science and Technology, Baotou, 014040, China.
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17
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Zhang TT, Guo SS, Wang HY, Jing Q, Yi X, Hu ZH, Yu XR, Xu TL, Liu MG, Zhao X. An Anterior Cingulate Cortex-to-Midbrain Projection Controls Chronic Itch in Mice. Neurosci Bull 2023; 39:793-807. [PMID: 36528690 PMCID: PMC10169993 DOI: 10.1007/s12264-022-00996-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/26/2022] [Indexed: 12/23/2022] Open
Abstract
Itch is an unpleasant sensation that provokes the desire to scratch. While acute itch serves as a protective system to warn the body of external irritating agents, chronic itch is a debilitating but poorly-treated clinical disease leading to repetitive scratching and skin lesions. However, the neural mechanisms underlying the pathophysiology of chronic itch remain mysterious. Here, we identified a cell type-dependent role of the anterior cingulate cortex (ACC) in controlling chronic itch-related excessive scratching behaviors in mice. Moreover, we delineated a neural circuit originating from excitatory neurons of the ACC to the ventral tegmental area (VTA) that was critically involved in chronic itch. Furthermore, we demonstrate that the ACC→VTA circuit also selectively modulated histaminergic acute itch. Finally, the ACC neurons were shown to predominantly innervate the non-dopaminergic neurons of the VTA. Taken together, our findings uncover a cortex-midbrain circuit for chronic itch-evoked scratching behaviors and shed novel insights on therapeutic intervention.
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Affiliation(s)
- Ting-Ting Zhang
- Department of Anesthesiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Su-Shan Guo
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Hui-Ying Wang
- Department of Anesthesiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Qi Jing
- Department of Anesthesiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Xin Yi
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Zi-Han Hu
- Department of Anesthesiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Xin-Ren Yu
- Department of Anesthesiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China
| | - Tian-Le Xu
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Ming-Gang Liu
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China.
| | - Xuan Zhao
- Department of Anesthesiology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, 200072, China.
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18
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Long JH, Wang PJ, Li ZF, Yao J, Li X, Wu B, Sui JF, Liao J, Wang P, Li XF, Liu SL. Dysgranular retrosplenial cortex modulates histaminergic and nonhistaminergic itch processing. Behav Brain Res 2023; 443:114306. [PMID: 36682500 DOI: 10.1016/j.bbr.2023.114306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/22/2023]
Abstract
Itch is an unpleasant sensation followed by an intense desire to scratch. Previous researches have advanced our understanding about the role of anterior cingulate cortex and prelimbic cortex in itch modulation, whereas little is known about the effects of retrosplenial cortex (RSC) during this process. Here we firstly confirmed that the neuronal activity of dysgranular RSC (RSCd) is significantly elevated during itch-scratching processing through c-Fos immunohistochemistry and fiber photometry recording. Then with designer receptors exclusively activated by designer drugs approaches, we found that pharmacogenetic inhibition of global RSCd neurons attenuated the number of scratching bouts as well as the cumulative duration of scratching bouts elicited by both 5-HT or compound 48/80 injection into rats' nape or cheek; selective inhibition of the pyramidal neurons in RSCd, or of the excitatory projections from caudal anterior cingulate cortex (cACC) to RSCd, demonstrated the similar effects of decreasing itch-related scratching induced by both 5-HT or compound 48/80. Pharmacogenetic intervention of the neuronal or circuitry activities did not affect rats' motor ability. This study presents direct evidence that pyramidal neurons in RSCd, and the excitatory projection from cACC to RSCd are critically involved in central regulation of both histaminergic and nonhistaminergic itch.
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Affiliation(s)
- Jun-Hui Long
- Department of Dermatology, The 958th Army Hospital of the Chinese People's Liberation Army, China
| | - Pu-Jun Wang
- Department of Dermatology, The 958th Army Hospital of the Chinese People's Liberation Army, China
| | - Zhi-Fang Li
- Department of Foreign Languages, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Juan Yao
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Xuan Li
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Bing Wu
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Jian-Feng Sui
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, Chongqing 400038, China
| | - Jun Liao
- Department of Dermatology, The 958th Army Hospital of the Chinese People's Liberation Army, China
| | - Ping Wang
- Department of Dermatology, The 958th Army Hospital of the Chinese People's Liberation Army, China
| | - Xiao-Feng Li
- Department of Radiology, the Third Affiliated Hospital of Chongqing Medical University, Chongqing 401120, China.
| | - Shu-Lei Liu
- Department of Dermatology, The 958th Army Hospital of the Chinese People's Liberation Army, China.
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19
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Wu XB, Zhu Q, Gao MH, Yan SX, Gu PY, Zhang PF, Xu ML, Gao YJ. Excitatory Projections from the Prefrontal Cortex to Nucleus Accumbens Core D1-MSNs and κ Opioid Receptor Modulate Itch-Related Scratching Behaviors. J Neurosci 2023; 43:1334-1347. [PMID: 36653189 PMCID: PMC9987576 DOI: 10.1523/jneurosci.1359-22.2023] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 12/28/2022] [Accepted: 01/06/2023] [Indexed: 01/20/2023] Open
Abstract
Itch is an uncomfortable and complex sensation that elicits the desire to scratch. The nucleus accumbens (NAc) activity is important in driving sensation, motivation, and emotion. Excitatory afferents from the medial prefrontal cortex (mPFC), amygdala, and hippocampus are crucial in tuning the activity of dopamine receptor D1-expressing and D2-expressing medium spiny neurons (Drd1-MSN and Drd2-MSN) in the NAc. However, a cell-type and neural circuity-based mechanism of the NAc underlying acute itch remains unclear. We found that acute itch induced by compound 48/80 (C48/80) decreased the intrinsic membrane excitability in Drd1-MSNs, but not in Drd2-MSNs, in the NAc core of male mice. Chemogenetic activation of Drd1-MSNs alleviated C48/80-induced scratching behaviors but not itch-related anxiety-like behaviors. In addition, C48/80 enhanced the frequency of spontaneous EPSCs (sEPSCs) and reduced the paired-pulse ratio (PPR) of electrical stimulation-evoked EPSCs in Drd1-MSNs. Furthermore, C48/80 increased excitatory synaptic afferents to Drd1-MSNs from the mPFC, not from the basolateral amygdala (BLA) or ventral hippocampus (vHipp). Consistently, the intrinsic excitability of mPFC-NAc projecting pyramidal neurons was increased after C48/80 treatment. Chemogenetic inhibition of mPFC-NAc excitatory synaptic afferents relieved the scratching behaviors. Moreover, pharmacological activation of κ opioid receptor (KOR) in the NAc core suppressed C48/80-induced scratching behaviors, and the modulation of KOR activity in the NAc resulted in the changes of presynaptic excitatory inputs to Drd1-MSNs in C48/80-treated mice. Together, these results reveal the neural plasticity in synapses of NAc Drd1-MSNs from the mPFC underlying acute itch and indicate the modulatory role of the KOR in itch-related scratching behaviors.SIGNIFICANCE STATEMENT Itch stimuli cause strongly scratching desire and anxiety in patients. However, the related neural mechanisms remain largely unclear. In the present study, we demonstrated that the pruritogen compound 48/80 (C48/80) shapes the excitability of dopamine receptor D1-expressing medium spiny neurons (Drd1-MSNs) in the nucleus accumbens (NAc) core and the glutamatergic synaptic afferents from medial prefrontal cortex (mPFC) to these neurons. Chemogenetic activation of Drd1-MSNs or inhibition of mPFC-NAc excitatory synaptic afferents relieves the scratching behaviors. In addition, pharmacological activation of κ opioid receptor (KOR) in the NAc core alleviates C48/80-induced itch. Thus, targeting mPFC-NAc Drd1-MSNs or KOR may provide effective treatments for itch.
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Affiliation(s)
- Xiao-Bo Wu
- Institute of Pain Medicine and Special Environmental Medicine, Co-innovation Center of Neuroregeneration, Nantong University, Jiangsu 226019, China
| | - Qian Zhu
- Institute of Pain Medicine and Special Environmental Medicine, Co-innovation Center of Neuroregeneration, Nantong University, Jiangsu 226019, China
| | - Ming-Hui Gao
- Institute of Pain Medicine and Special Environmental Medicine, Co-innovation Center of Neuroregeneration, Nantong University, Jiangsu 226019, China
| | - Sheng-Xiang Yan
- Institute of Pain Medicine and Special Environmental Medicine, Co-innovation Center of Neuroregeneration, Nantong University, Jiangsu 226019, China
| | - Pan-Yang Gu
- Institute of Pain Medicine and Special Environmental Medicine, Co-innovation Center of Neuroregeneration, Nantong University, Jiangsu 226019, China
| | - Peng-Fei Zhang
- Institute of Pain Medicine and Special Environmental Medicine, Co-innovation Center of Neuroregeneration, Nantong University, Jiangsu 226019, China
| | - Meng-Lin Xu
- Institute of Pain Medicine and Special Environmental Medicine, Co-innovation Center of Neuroregeneration, Nantong University, Jiangsu 226019, China
| | - Yong-Jing Gao
- Institute of Pain Medicine and Special Environmental Medicine, Co-innovation Center of Neuroregeneration, Nantong University, Jiangsu 226019, China
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20
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Liang TY, Zhou H, Sun YG. Distinct Roles of Dopamine Receptor Subtypes in the Nucleus Accumbens during Itch Signal Processing. J Neurosci 2022; 42:8842-8854. [PMID: 36241382 PMCID: PMC9698675 DOI: 10.1523/jneurosci.0821-22.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 09/20/2022] [Accepted: 09/26/2022] [Indexed: 12/29/2022] Open
Abstract
Ventral tegmental area (VTA) dopaminergic neurons, which are well known for their central roles in reward and motivation-related behaviors, have been shown to participate in itch processing via their projection to the nucleus accumbens (NAc). However, the functional roles of different dopamine receptor subtypes in subregions of the NAc during itch processing remain unknown. With pharmacological approaches, we found that the blockade of dopamine D1 receptors (D1R), but not dopamine D2 receptors (D2R), in the lateral shell (LaSh) of the NAc impaired pruritogen-induced scratching behavior in male mice. In contrast, pharmacological activation of D2R in both the LaSh and medial shell (MeSh) of the NAc attenuated the scratching behavior induced by pruritogens. Consistently, we found that dopamine release, as detected by a dopamine sensor, was elevated in the LaSh rather than the MeSh of the NAc at the onset of scratching behavior. Furthermore, the elevation of dopamine release in the LaSh of the NAc persisted even though itch-relieving behavior was blocked, suggesting that the dopamine signal in the NAc LaSh represents a motivational component of itch processing. Our study revealed different dynamics of dopamine release that target neurons expressing two dopamine receptors subtypes within different subregions of the NAc, and emphasized that D1R in the LaSh of the NAc is important in itch signal processing.SIGNIFICANCE STATEMENT Dopamine has been implicated in itch signal processing. However, the mechanism underlying the functional role of dopamine in itch processing remains largely unknown. Here, we examined the role of dopamine D1 receptor (D1R) and D2R in the nucleus accumbens (NAc) shell during pruritogen-induced scratching behavior. We demonstrated that D1R in the NAc lateral shell (LaSh) play an important role in motivating itch-induced scratching behavior, while activation of D2R would terminate scratching behavior. Our study revealed the diverse functional roles of dopamine signals in the NAc shell during itch processing.
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Affiliation(s)
- Tong-Yu Liang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hua Zhou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yan-Gang Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
- Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 201210, China
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21
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Chen M, He T, Yi XH, Tang MC, Long JH, Wang PJ, Liu J, Yao J, Li HL, Sui JF, Wu GY. Infralimbic cortex–medial striatum projections modulate the itch processing. Exp Neurol 2022; 354:114101. [DOI: 10.1016/j.expneurol.2022.114101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 03/11/2022] [Accepted: 04/26/2022] [Indexed: 11/04/2022]
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22
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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: 1.7] [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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23
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Piyush Shah D, Barik A. The Spino-Parabrachial Pathway for Itch. Front Neural Circuits 2022; 16:805831. [PMID: 35250493 PMCID: PMC8891797 DOI: 10.3389/fncir.2022.805831] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 01/03/2022] [Indexed: 11/13/2022] Open
Abstract
Itch-induced scratching is an evolutionarily conserved behavioral response that protects organisms from potential parasites/irritants in their immediate vicinity. How the exposure to a pruritogen is translated to the perception of itch and how that perception drives scratching directed towards the site of exposure remains poorly understood. In this review, we focus on the recent findings that shed light on the neural pathways in the brain that underlie itch-induced scratching. We compare the molecularly defined itch pathways with the known pain circuits as they have anatomical and functional overlap. We review the roles played by the neurons in the spinoparabrachial pathway-comprising of the neurons in the spinal cord and the parabrachial nucleus (PBN), which acts as a hub for transmitting itch information across the brain. Lastly, we deliberate on scratching as a behavioral measure of the intensity of itch and its implication in unraveling the underlying supraspinal mechanisms. In summary, we provide a resource on the recent advances and discuss a path forward on our understanding of the neural circuits for itch.
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Affiliation(s)
| | - Arnab Barik
- Centre for Neuroscience, Indian Institute of Science, Bengaluru, India
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24
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Colocalized, bidirectional optogenetic modulations in freely behaving mice with a wireless dual-color optoelectronic probe. Nat Commun 2022; 13:839. [PMID: 35149715 PMCID: PMC8837785 DOI: 10.1038/s41467-022-28539-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 02/02/2022] [Indexed: 02/06/2023] Open
Abstract
Optogenetic methods provide efficient cell-specific modulations, and the ability of simultaneous neural activation and inhibition in the same brain region of freely moving animals is highly desirable. Here we report bidirectional neuronal activity manipulation accomplished by a wireless, dual-color optogenetic probe in synergy with the co-expression of two spectrally distinct opsins (ChrimsonR and stGtACR2) in a rodent model. The flexible probe comprises vertically assembled, thin-film microscale light-emitting diodes with a lateral dimension of 125 × 180 µm2, showing colocalized red and blue emissions and enabling chronic in vivo operations with desirable biocompatibilities. Red or blue irradiations deterministically evoke or silence neurons co-expressing the two opsins. The probe interferes with dopaminergic neurons in the ventral tegmental area of mice, increasing or decreasing dopamine levels. Such bidirectional regulations further generate rewarding and aversive behaviors and interrogate social interactions among multiple mice. These technologies create numerous opportunities and implications for brain research.
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25
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The Spinal-Parabrachial-Mesencephalic Circuit: A Possible Explanation of How Pain Leads to Emotional Disorders. Neurosci Bull 2022; 38:456-458. [PMID: 35113329 PMCID: PMC9068842 DOI: 10.1007/s12264-022-00823-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 12/03/2021] [Indexed: 10/19/2022] Open
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26
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Chen XJ, Liu YH, Xu NL, Sun YG. Itch perception is reflected by neuronal ignition in the primary somatosensory cortex. Natl Sci Rev 2021; 9:nwab218. [PMID: 35769233 PMCID: PMC9232292 DOI: 10.1093/nsr/nwab218] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 11/26/2021] [Accepted: 11/26/2021] [Indexed: 11/19/2022] Open
Abstract
Multiple cortical areas including the primary somatosensory cortex (S1) are activated during itch signal processing, yet cortical representation of itch perception remains unknown. Using novel miniature two-photon microscopic imaging in free-moving mice, we investigated the coding of itch perception in S1. We found that pharmacological inactivation of S1 abolished itch-induced scratching behavior, and the itch-induced scratching behavior could be well predicted by the activity of a fraction of layer 2/3 pyramidal neurons, suggesting that a subpopulation of S1 pyramidal neurons encoded itch perception, as indicated by immediate subsequent scratching behaviors. With a newly established optogenetics-based paradigm that allows precisely controlled pruritic stimulation, we found that a small fraction of S1 neurons exhibited an ignition-like pattern at the detection threshold of itch perception. Our study revealed the neural mechanism underlying itch perceptual coding in S1, thus paving the way for the study of cortical representation of itch perception at the single-neuron level in freely moving animals.
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Affiliation(s)
- Xiao-Jun Chen
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan-He Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ning-Long Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 201210, China
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27
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Mamuladze T, Kim BS. The Sensation of Itch: From Biological Discovery to Medical Treatment. J Invest Dermatol 2021; 142:21-22. [PMID: 34801533 DOI: 10.1016/j.jid.2021.10.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 10/19/2022]
Affiliation(s)
- Tornike Mamuladze
- Division of Biology and Biomedical Sciences (DBBS), Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Brian S Kim
- Division of Biology and Biomedical Sciences (DBBS), Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA; Center for the Study of Itch & Sensory Disorders, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA; Division of Dermatology, Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA; Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA.
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28
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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: 20] [Impact Index Per Article: 5.0] [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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29
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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: 32] [Impact Index Per Article: 8.0] [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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30
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Abstract
Mechanistic theories of itch are based on neuronal specificity, stimulus intensity, and temporal or spatial discharge patterns. Traditionally, these theories are conceptualized as mutually exclusive, assuming that finding evidence for one theory would exclude the others and could sufficiently explain itch. Current experimental data primarily support the specificity or pattern theory of itch. However, in contrast to an assumed inherent exclusivity, recent results have shown that even within itch-specific pathways in the spinal cord, temporal discharge patterns are important as sustained pruriceptor is required to allow successful transsynaptic signal progression. Also, optogenetic activation of pruriceptors suggest that the combination of neuronal specificity and temporal pattern determines the sensory effect: tonic activation of pruriceptors is required to induce scratching behavior whereas short-lasting stimulation rather causes withdrawal. In addition to the mere duration of discharge, also the temporal pattern or spatial aspects could critically contribute to elicit pruritus instead of pain. Basic neurophysiological studies trying to validate neuronal theories for pruritus in their pure form provide unitary concepts leading from neuronal discharge to the itch sensation. However, the crucial clinical questions have the opposite perspective: which mechanisms explain the chronic itch in a given patient or a given disease? In trying to solve these clinical problems we should not feel bound to the mutual exclusive nature of itch theories, but rather appreciate blending several theories and also accept combinations of itch and pain. Thus, blended versions of itch theories might better suffice for an explanation of chronic itch in patients and will improve the basis for mechanistic treatment options.
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Affiliation(s)
- Martin Schmelz
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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31
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Haruta-Tsukamoto A, Miyahara Y, Funahashi H, Nishimori T, Ishida Y. Perampanel attenuates scratching behavior induced by acute or chronic pruritus in mice. Biochem Biophys Res Commun 2020; 533:1102-1108. [PMID: 33028486 DOI: 10.1016/j.bbrc.2020.09.109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 09/24/2020] [Indexed: 11/28/2022]
Abstract
An itch is defined as an unpleasant sensation that evokes a desire to scratch. Glutamate is a major excitatory neurotransmitter in the mammalian central nervous system and has a crucial role in pruriceptive processing in the spinal dorsal horn. It is well known that glutamate exerts its effects by binding to various glutamate receptors including α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, and that AMPA/kainate receptors play a crucial role in pruriceptive processing; however, the precise role of AMPA receptors remains uncertain. Perampanel, an antiepileptic drug, is an antagonist of AMPA receptors. Pretreatment with perampanel dose-dependently attenuated the induction of scratching, a behavior typically associated with pruritus, by intradermal administration of the pruritogen chloroquine. In addition, the induction of scratching in mice painted with diphenylcyclopropenone and NC/Nga mice treated with Biostir AD, animal models of contact dermatitis and atopic dermatitis, respectively, was dose-dependently alleviated by administration of perampanel. These findings indicate that AMPA receptors play a crucial role in pruriceptive processing in mice with acute or chronic pruritus.
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Affiliation(s)
- Ayaka Haruta-Tsukamoto
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki, 889-1692, Japan
| | - Yu Miyahara
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki, 889-1692, Japan
| | - Hideki Funahashi
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki, 889-1692, Japan
| | - Toshikazu Nishimori
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki, 889-1692, Japan
| | - Yasushi Ishida
- Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki, 889-1692, Japan.
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Setsu T, Hamada Y, Oikawa D, Mori T, Ishiuji Y, Sato D, Narita M, Miyazaki S, Furuta E, Suda Y, Sakai H, Ochiya T, Tezuka H, Iseki M, Inada E, Yamanaka A, Kuzumaki N, Narita M. Direct evidence that the brain reward system is involved in the control of scratching behaviors induced by acute and chronic itch. Biochem Biophys Res Commun 2020; 534:624-631. [PMID: 33220930 DOI: 10.1016/j.bbrc.2020.11.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 11/09/2020] [Indexed: 01/17/2023]
Abstract
In the present study, we demonstrated that there is a direct relationship between scratching behaviors induced by itch and functional changes in the brain reward system. Using a conditional place preference test, the rewarding effect was clearly evoked by scratching under both acute and chronic itch stimuli. The induction of ΔFosB, a member of the Fos family of transcription factors, was observed in dopamine transporter (DAT)-positive dopamine neurons in the ventral tegmental area (VTA) of mice suffering from a chronic itch sensation. Based on a cellular analysis of scratching-activated neurons, these neurons highly expressed tyrosine hydroxylase (TH) and DAT genes in the VTA. Furthermore, in an in vivo microdialysis study, the levels of extracellular dopamine in the nucleus accumbens (NAcc) were significantly increased by transient scratching behaviors. To specifically suppress the mesolimbic dopaminergic pathway using pharmacogenetics, we used the TH-cre/hM4Di mice. Pharmacogenetic suppression of mesolimbic dopaminergic neurons significantly decreased scratching behaviors. Under the itch condition with scratching behaviors restricted by an Elizabethan collar, the induction of ΔFosB was found mostly in corticotropin-releasing hormone (CRH)-containing neurons of the hypothalamic paraventricular nucleus (PVN). These findings suggest that repetitive abnormal scratching behaviors under acute and chronic itch stimuli may activate mesolimbic dopamine neurons along with pleasant emotions, while the restriction of such scratching behaviors may initially induce the activation of PVN-CRH neurons associated with stress.
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Affiliation(s)
- Takao Setsu
- Department of Anesthesiology and Pain Medicine, Juntendo University School of Medicine, Tokyo, Japan; Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan
| | - Yusuke Hamada
- Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan; Division of Cancer Pathophysiology, National Cancer Center Research Institute, Tokyo, Japan
| | - Daisuke Oikawa
- Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan
| | - Tomohisa Mori
- Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan
| | - Yozo Ishiuji
- Department of Dermatology, The Jikei University School of Medicine, Tokyo, Japan
| | - Daisuke Sato
- Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan
| | - Michiko Narita
- Division of Cancer Pathophysiology, National Cancer Center Research Institute, Tokyo, Japan; Department of Molecular and Cellular Medicine, Institute of Medical Science, Tokyo Medical University, Tokyo, Japan
| | - Shogo Miyazaki
- Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan
| | - Eri Furuta
- Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan
| | - Yukari Suda
- Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan; Division of Cancer Pathophysiology, National Cancer Center Research Institute, Tokyo, Japan
| | - Hiroyasu Sakai
- Department of Biomolecular Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan
| | - Takahiro Ochiya
- Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan; Department of Molecular and Cellular Medicine, Institute of Medical Science, Tokyo Medical University, Tokyo, Japan
| | - Hiroyuki Tezuka
- Department of Cellular Function Analysis, Research Promotion and Support Headquarters, Fujita Health University, Aichi, Japan
| | - Masako Iseki
- Department of Anesthesiology and Pain Medicine, Juntendo University School of Medicine, Tokyo, Japan
| | - Eiichi Inada
- Department of Anesthesiology and Pain Medicine, Juntendo University School of Medicine, Tokyo, Japan
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Aichi, Japan
| | - Naoko Kuzumaki
- Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan.
| | - Minoru Narita
- Department of Anesthesiology and Pain Medicine, Juntendo University School of Medicine, Tokyo, Japan; Department of Pharmacology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Tokyo, Japan; Division of Cancer Pathophysiology, National Cancer Center Research Institute, Tokyo, Japan.
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33
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Substance use disorders and chronic itch. J Am Acad Dermatol 2020; 84:148-155. [PMID: 32891774 DOI: 10.1016/j.jaad.2020.08.117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/26/2020] [Accepted: 08/30/2020] [Indexed: 12/11/2022]
Abstract
Chronic pruritus is one dermatologic manifestation of an underlying substance use disorder. Recent literature has uncovered similarities between the general neurologic mechanisms of addiction and chronic itch, largely involving activation of the dopaminergic reward circuits within the brain and imbalances between mu and kappa opioid receptor activation. It is likely that the use of specific drugs, like central nervous system stimulants and opioids, results in further activation and imbalances within these pathways, perpetuating both addiction and pruritus simultaneously. Opioid users often present to dermatology clinics with a generalized pruritus, whereas individuals using central nervous system stimulants like cocaine and methylenedioxymethamphetamine (MDMA), as well as legally prescribed drugs like treatments for attention deficit hyperactivity disorder, frequently complain of crawling, delusional infestation-like sensations underneath the skin. Because of these overlapping mechanisms and similar clinical presentations to many other chronically itchy conditions, it is necessary for dermatologists to consider and investigate an underlying substance use disorder to effectively treat these patients.
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Posterior Thalamic Nucleus Mediates Facial Histaminergic Itch. Neuroscience 2020; 444:54-63. [PMID: 32750381 DOI: 10.1016/j.neuroscience.2020.07.048] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 07/13/2020] [Accepted: 07/27/2020] [Indexed: 11/24/2022]
Abstract
Itch induces a desire to scratch and leads to skin damage in some severe conditions. Much progress has been made in the peripheral and spinal level, and recent findings suggested that we need to focus on the central circuitry mechanism. However, the functional role of the thalamus in itch signal processing remains largely unknown. We showed that the posterior thalamic nucleus (Po) played a vital role in modulating facial histaminergic itch signal processing. We found that the calcium signal of Po neurons was increased during the histaminergic itch-induced scratching behavior in the cheek model, and pharmacogenetic suppression of Po neurons reduced the scratching behaviors. Retrograde mapping results suggested that the Po receives information from the somatosensory cortex, motor cortex, parabrachial nucleus (PBN), the principal sensory trigeminal nucleus (PrV) and the spinal trigeminal nucleus (SpV), which participate in itch signal transmission from head and body. Thus, our study indicates that the Po is critical in modulating facial histaminergic itch signal processing.
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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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36
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Coddington LT, Dudman JT. Learning from Action: Reconsidering Movement Signaling in Midbrain Dopamine Neuron Activity. Neuron 2020; 104:63-77. [PMID: 31600516 DOI: 10.1016/j.neuron.2019.08.036] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/10/2019] [Accepted: 08/22/2019] [Indexed: 01/07/2023]
Abstract
Animals infer when and where a reward is available from experience with informative sensory stimuli and their own actions. In vertebrates, this is thought to depend upon the release of dopamine from midbrain dopaminergic neurons. Studies of the role of dopamine have focused almost exclusively on their encoding of informative sensory stimuli; however, many dopaminergic neurons are active just prior to movement initiation, even in the absence of sensory stimuli. How should current frameworks for understanding the role of dopamine incorporate these observations? To address this question, we review recent anatomical and functional evidence for action-related dopamine signaling. We conclude by proposing a framework in which dopaminergic neurons encode subjective signals of action initiation to solve an internal credit assignment problem.
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Ishiuji Y. Addiction and the itch‐scratch cycle. What do they have in common? Exp Dermatol 2019; 28:1448-1454. [DOI: 10.1111/exd.14029] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 07/15/2019] [Accepted: 08/26/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Yozo Ishiuji
- Department of Dermatology The Jikei University School of Medicine Tokyo Japan
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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: 61] [Impact Index Per Article: 10.2] [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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39
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Topography of Reward and Aversion Encoding in the Mesolimbic Dopaminergic System. J Neurosci 2019; 39:6472-6481. [PMID: 31217328 DOI: 10.1523/jneurosci.0271-19.2019] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/29/2019] [Accepted: 06/05/2019] [Indexed: 11/21/2022] Open
Abstract
Dopamine (DA) neurons in the VTA play essential roles in adaptive motivated behavior, which requires rapid discrimination between positive and negative motivational signature. However, the precise functional DA circuitry processing reward and aversive information remain elusive. Here, we report that the encoding of reward and aversion by the DA system in the NAc is tightly associated with its anatomical location. By recording the dynamics of DA release with genetically encoded fluorescent DA sensor using in vivo fiber photometry in freely moving male mice, we found that the DA-sensor signal in the dorsomedial NAc shell and dorsolateral NAc shell were increased during rewarding events and decreased during aversive noxious events. In contrast, the release of DA in the ventromedial NAc shell was increased by both rewarding and aversive stimuli, whereas the DA-sensor signal in the central ventromedial NAc shell and ventrolateral NAc shell showed complex dynamics. Furthermore, the activity of DA fibers in different subregions of NAc measured with calcium sensor largely recapitulated the changes of DA-sensor signal in response to rewarding and aversive stimuli. In addition, correlation analysis showed that the response magnitude of DA-sensor or fibers significantly changed along the DV axis of the NAc. These results revealed the distinct role of the mesolimbic DA system in different subregions of NAc in encoding value and salience.SIGNIFICANCE STATEMENT Adaptive motivated behavior requires rapid discrimination between favorable and harmful events and is dynamically modulated by dopamine (DA) neurons in the VTA. However, the precise relationship between distinct DA circuitry and reward/aversion signal encoding is not well understood. Here, by recording the dynamics of DA release and the activity of DA fibers in each subregion of the NAc using in vivo fiber photometry in freely moving animals, we found that the DA system in the dorsomedial/dorsolateral, ventromedial, and ventrolateral NAc shell plays different roles in encoding value and salience. These results extend our knowledge about how the mesolimbic DA system process motivational information at the circuitry level.
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40
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Su XY, Chen M, Yuan Y, Li Y, Guo SS, Luo HQ, Huang C, Sun W, Li Y, Zhu MX, Liu MG, Hu J, Xu TL. Central Processing of Itch in the Midbrain Reward Center. Neuron 2019; 102:858-872.e5. [PMID: 31000426 DOI: 10.1016/j.neuron.2019.03.030] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 12/28/2018] [Accepted: 03/19/2019] [Indexed: 10/27/2022]
Abstract
Itch is an aversive sensation that evokes a desire to scratch. Paradoxically, scratching the itch also produces a hedonic experience. The specific brain circuits processing these different aspects of itch, however, remain elusive. Here, we report that GABAergic (GABA) and dopaminergic (DA) neurons in the ventral tegmental area (VTA) are activated with different temporal patterns during acute and chronic itch. DA neuron activation lags behind GABA neurons and is dependent on scratching of the itchy site. Optogenetic manipulations of VTA GABA neurons rapidly modulated scratching behaviors through encoding itch-associated aversion. In contrast, optogenetic manipulations of VTA DA neurons revealed their roles in sustaining recurrent scratching episodes through signaling scratching-induced reward. A similar dichotomy exists for the role of VTA in chronic itch. These findings advance understanding of circuit mechanisms of the unstoppable itch-scratch cycles and shed important insights into chronic itch therapy.
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Affiliation(s)
- Xin-Yu Su
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Ming Chen
- iHuman Institute, ShanghaiTech University, Shanghai 201210, China
| | - Yuan Yuan
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ying Li
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Su-Shan Guo
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Huo-Qing Luo
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Chen Huang
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Wenzhi Sun
- iHuman Institute, ShanghaiTech University, Shanghai 201210, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Yong Li
- Collaborative Innovation Center for Brain Science, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai 201210, China
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ming-Gang Liu
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
| | - Ji Hu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai 201210, China.
| | - Tian-Le Xu
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai 201210, China.
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41
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Dong H, Wang J, Yang YF, Shen Y, Qu WM, Huang ZL. Dorsal Striatum Dopamine Levels Fluctuate Across the Sleep-Wake Cycle and Respond to Salient Stimuli in Mice. Front Neurosci 2019; 13:242. [PMID: 30949023 PMCID: PMC6436203 DOI: 10.3389/fnins.2019.00242] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 03/01/2019] [Indexed: 01/07/2023] Open
Abstract
Dopamine is involved in numerous neurological processes, and its deficiency has been implicated in Parkinson’s disease, whose patients suffer from severe sleep disorders. Destruction of nigrostriatal dopaminergic neurons or dorsal striatum disrupts the sleep–wake cycle. However, whether striatal dopamine levels correlate with vigilance states still remains to be elucidated. Here, we employed an intensity-based genetically encoded dopamine indicator, dLight1.1, to track striatal dopamine levels across the spontaneous sleep–wake cycle and the dopaminergic response to external stimuli. We found that the striatal dLight1.1 signal was at its highest during wakefulness, lower during non-rapid eye movement (non-REM or NREM) sleep, and lowest during REM sleep. Moreover, the striatal dLight1.1 signal increased significantly during NREM sleep-to-wake transitions, while it decreased during wake-to-NREM sleep transitions. Furthermore, different external stimuli, such as sudden door-opening of the home cage or cage-change to a new environment, caused striatal dopamine release, whereas an unexpected auditory tone did not. Finally, despite both modafinil and caffeine being wake-promoting agents that increased wakefulness, modafinil increased striatal dopamine levels while caffeine did not. Taken together, our findings demonstrated that striatal dopamine levels correlated with the spontaneous sleep–wake cycle and responded to specific external stimuli as well as the stimulant modafinil.
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Affiliation(s)
- Hui Dong
- Department of Pharmacology, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Juan Wang
- Department of Pharmacology, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yan-Fei Yang
- Department of Pharmacology, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yan Shen
- Department of Pharmacology, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China.,Department of Neurology and National Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Wei-Min Qu
- Department of Pharmacology, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Zhi-Li Huang
- Department of Pharmacology, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
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