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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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2
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Rojas-Carvajal M, Leandro R, Brenes JC. Distinct acute stressors exert an antagonistic effect on complex grooming during novelty habituation in rats. Behav Processes 2023; 212:104931. [PMID: 37598764 DOI: 10.1016/j.beproc.2023.104931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/07/2023] [Accepted: 08/15/2023] [Indexed: 08/22/2023]
Abstract
Grooming is a common readout in multiple rat models of neuropsychiatric diseases. It is usually associated with distress and negative emotionality, but also with emotional de-arousal after stress. These seemingly conflicting interpretations may result from specific grooming sequences appearing at different arousal levels and during distinct phases of the stress response. To further explore this hypothesis, we analyzed how distinct stressors affect grooming syntaxis and kinetics. To that end, we explored the independent and interacting effects of foot shocks, corticosterone (CORT), and novelty on exploratory activity, grooming, and ultrasonic vocalizations (USVs) in an open-field test (OF). Wistar rats were intraperitoneally injected either with vehicle or CORT, placed in a chamber where half of them were foot-shocked and then assessed in the OF. The next day, animals were re-exposed to the shock chamber and then tested in the OF without receiving any treatment. On day 1, foot shocks and -to a less extent CORT- increased freezing and inhibited rearing in the chamber, but only foot shocks increased distress USVs. In the OF, both treatments suppressed complex grooming, with foot-shocks also inhibiting exploration and CORT marginally reducing rearing. On day 2, foot-shocked rats showed conditioned fear when re-exposed to the chamber. When tested in the OF, foot-shocked and CORT-treated animals still showed low levels of complex grooming, with the former group also showing increased distress USVs. In this study, all different stressors inhibited complex grooming, suggesting an inverse association between these grooming subtypes and negative emotionality.
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Affiliation(s)
- Mijail Rojas-Carvajal
- Neuroscience Research Center, University of Costa Rica, Montes de Oca, San José, Costa Rica; Institute for Psychological Research, University of Costa Rica, Montes de Oca, San José, Costa Rica.
| | - Rita Leandro
- Neuroscience Research Center, University of Costa Rica, Montes de Oca, San José, Costa Rica; Institute for Psychological Research, University of Costa Rica, Montes de Oca, San José, Costa Rica
| | - Juan C Brenes
- Neuroscience Research Center, University of Costa Rica, Montes de Oca, San José, Costa Rica; Institute for Psychological Research, University of Costa Rica, Montes de Oca, San José, Costa Rica
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3
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Jiang S, Wang YS, Zheng XX, Zhao SL, Wang Y, Sun L, Chen PH, Zhou Y, Tin C, Li HL, Sui JF, Wu GY. Itch-specific neurons in the ventrolateral orbital cortex selectively modulate the itch processing. SCIENCE ADVANCES 2022; 8:eabn4408. [PMID: 35905177 PMCID: PMC9337765 DOI: 10.1126/sciadv.abn4408] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 06/16/2022] [Indexed: 05/31/2023]
Abstract
Itch is a cutaneous sensation that is critical in driving scratching behavior. The long-standing question of whether there are specific neurons for itch modulation inside the brain remains unanswered. Here, we report a subpopulation of itch-specific neurons in the ventrolateral orbital cortex (VLO) that is distinct from the pain-related neurons. Using a Tet-Off cellular labeling system, we showed that local inhibition or activation of these itch-specific neurons in the VLO significantly suppressed or enhanced itch-induced scratching, respectively, whereas the intervention did not significantly affect pain. Conversely, suppression or activation of pain-specific neurons in the VLO significantly affected pain but not itch. Moreover, fiber photometry and immunofluorescence verified that these itch- and pain-specific neurons are distinct in their functional activity and histological location. In addition, the downstream targets of itch- and pain-specific neurons were different. Together, the present study uncovers an important subpopulation of neurons in the VLO that specifically modulates itch processing.
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Affiliation(s)
- Shan Jiang
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Yi-Song Wang
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Xiao-Xia Zheng
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Shan-Lan Zhao
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Yi Wang
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Lin Sun
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, China
| | - Peng-Hui Chen
- Department of Neurobiology, Army Medical University, Chongqing 400038, China
| | - Yi Zhou
- Department of Neurobiology, Army Medical University, Chongqing 400038, China
| | - Chung Tin
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, SAR, People’s Republic of China
| | - Hong-Li Li
- Experimental Center of Basic Medicine, Army Medical University, Chongqing 400038, 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
| | - Guang-Yan Wu
- 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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4
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Mechanisms of Broad-Band UVB Irradiation‒Induced Itch in Mice. J Invest Dermatol 2021; 141:2499-2508.e3. [PMID: 33812858 DOI: 10.1016/j.jid.2021.03.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/02/2021] [Accepted: 03/09/2021] [Indexed: 11/24/2022]
Abstract
Although sunburn can produce severe uncontrollable itching, the underlying mechanisms of UV irradiation‒induced itch are poorly understood because of a lack of experimental animal models of sunburn itch. In this study, we established a sunburn-related mouse model and found that broad-band UVB irradiation elicited scratching but not wiping behavior in mice. Using a combination of live-cell calcium ion imaging and quantitative RT-PCR on dorsal root ganglion neurons, H&E staining, immunofluorescence staining of skin preparations, and behavioral testing, in combination with genetic and pharmacological approaches, we showed that TRPV1-positive dorsal root ganglion neurons but not mast cells are involved in broad-band UVB irradiation‒induced itch. Moreover, both genetic and pharmacological inhibition of TRPV1 function significantly alleviated the broad-band UVB irradiation‒induced itch response. Collectively, our results suggest that broad-band UVB irradiation evokes itch sensation in mice by promoting TRPV1 channel function in dorsal root ganglion neurons and provide potential therapeutic targets for sunburn-related itch.
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5
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Zhang D, Men H, Zhang L, Gao X, Wang J, Li L, Zhu Q, Zhang H, Jia Z. Inhibition of M/K v7 Currents Contributes to Chloroquine-Induced Itch in Mice. Front Mol Neurosci 2020; 13:105. [PMID: 32694980 PMCID: PMC7339983 DOI: 10.3389/fnmol.2020.00105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 05/20/2020] [Indexed: 01/31/2023] Open
Abstract
M/Kv7 potassium channels play a key role in regulation of neuronal excitability. Modulation of neuronal excitability of primary sensory neurons determines the itch sensation induced by a variety of itch-causing substances including chloroquine (CQ). In the present study, we demonstrate that suppression of M/Kv7 channel activity contributes to generation of itch in mice. CQ enhances excitability of the primary sensory neurons through inhibiting M/Kv7 potassium currents in a Ca2+ influx-dependent manner. Specific M/Kv7 channel opener retigabine (RTG) or tannic acid (TA) not only reverses the CQ-induced enhancement of neuronal excitability but also suppresses the CQ-induced itch behavior. Systemic application of RTG or TA also significantly inhibits the itch behavior induced by a variety of pruritogens. Taken together, our findings provide novel insight into the molecular basis of CQ-induced itch sensation in mammals that can be applied to the development of strategies to mitigate itch behavior.
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Affiliation(s)
- Dong Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China.,Department of Anesthesiology, Hebei General Hospital, Shijiazhuang, China
| | - Hongchao Men
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China.,Department of Anesthesiology, Hebei General Hospital, Shijiazhuang, China
| | - Ludi Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Xiangxin Gao
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Jingjing Wang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Leying Li
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Qiaoying Zhu
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Hailin Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Zhanfeng Jia
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
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6
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Domocos D, Selescu T, Ceafalan LC, Iodi Carstens M, Carstens E, Babes A. Role of 5-HT1A and 5-HT3 receptors in serotonergic activation of sensory neurons in relation to itch and pain behavior in the rat. J Neurosci Res 2020; 98:1999-2017. [PMID: 32537854 DOI: 10.1002/jnr.24633] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 03/29/2020] [Accepted: 04/10/2020] [Indexed: 12/21/2022]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) released by platelets, mast cells, and immunocytes is a potent inflammatory mediator which modulates pain and itch sensing in the peripheral nervous system. The serotonergic receptors expressed by primary afferent neurons involved in these sensory functions are not fully identified and appear to be to a large extent species dependent. Moreover, the mechanisms through which 5-HT receptor activation is coupled to changes in neuronal excitability have not been completely revealed. Using a combination of in vitro (calcium and voltage imaging and patch-clamp) and in vivo behavioral methods, we used both male and female Wistar rats to provide evidence for the involvement of two 5-HT receptor subtypes, 5-HT1A and 5-HT3, in mediating the sustained and transient effects, respectively, of 5-HT on rat primary afferent neurons involved in pain and itch processing. In addition, our results are consistent with a model in which sustained serotonergic responses triggered via the 5-HT1A receptor are due to closure of background potassium channels, followed by membrane depolarization and action potentials, during which the activation of voltage-gated calcium channels leads to calcium entry. Our results may provide a better understanding of mammalian serotonergic itch signaling.
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Affiliation(s)
- Dan Domocos
- Department of Anatomy, Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Tudor Selescu
- Department of Anatomy, Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Laura Cristina Ceafalan
- Cell Biology, Neuroscience and Experimental Myology Laboratory, 'Victor Babeș' National Institute of Pathology, Bucharest, Romania.,Department of Cellular & Molecular Biology and Histology, School of Medicine, 'Carol Davila' University of Medicine and Pharmacy, Bucharest, Romania
| | - Mirela Iodi Carstens
- Department of Neurobiology, Physiology and Behavior, College of Biological Sciences, University of California, Davis, CA, USA
| | - Earl Carstens
- Department of Neurobiology, Physiology and Behavior, College of Biological Sciences, University of California, Davis, CA, USA
| | - Alexandru Babes
- Department of Anatomy, Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, Romania
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7
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Abstract
Trigeminal spinal subnucleus caudalis (Vc) neurons that project to the ventral posteromedial thalamic nucleus (VPM) and parabrachial nucleus (PBN) are critical for orofacial pain processing. We hypothesized that persistent trigeminal nerve injury differentially alters the proportion of Vc neurons that project to VPM and PBN in a modality-specific manner. Neuroanatomical approaches were used to quantify the number of Vc neurons projecting to VPM or PBN after chronic constriction injury of the infraorbital nerve (ION-CCI) and subsequent upper-lip stimulation. Male rats received injections of retrograde tracer fluorogold into the contralateral VPM or PBN on day 7 after ION-CCI, and at 3 days after that, either capsaicin injection or noxious mechanical stimulation was applied to the upper lip ipsilateral to nerve injury. Infraorbital nerve chronic constriction injury rats displayed greater forelimb wiping to capsaicin injection and mechanical allodynia of the lip than sham rats. Total cell counts for phosphorylated extracellular signal-regulated kinase-immunoreactive (pERK-IR) neurons after capsaicin or mechanical lip stimuli were higher in ION-CCI than sham rats as was the percentage of pERK-IR PBN projection neurons. However, the percentage of pERK-IR VPM projection neurons was also greater in ION-CCI than sham rats after capsaicin but not mechanical lip stimuli. The present findings suggest that persistent trigeminal nerve injury increases the number of Vc neurons activated by capsaicin or mechanical lip stimuli. By contrast, trigeminal nerve injury modifies the proportion of Vc nociceptive neurons projecting to VPM and PBN in a stimulus modality-specific manner and may reflect differential involvement of ascending pain pathways receiving C fiber and mechanosensitive afferents.
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8
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Rinaldi G. The Itch-Scratch Cycle: A Review of the Mechanisms. Dermatol Pract Concept 2019; 9:90-97. [PMID: 31106010 PMCID: PMC6502296 DOI: 10.5826/dpc.0902a03] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/28/2019] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Despite being one of the most common presenting dermatological symptoms, itching continues to perplex health care professionals because it is notoriously difficult to control. OBJECTIVE This review gathers evidence to answer the 2-part question, "Why do we itch and scratch?" by exploring the history of itchy disease, the neurobiology of itch, and the 4 different clinical origins of itch: pruritogenic, neurological, neuropathic, and psychological. RESULTS The automated scratching reflex and its biological and psychological reasons for existence are complicated and poorly understood. Currently, there are a myriad of treatments available for individuals suffering from this condition; however, many remain symptomatic. CONCLUSIONS The itch-scratch cycle is a complex pain-like sensation with a reflex-like response. In the future, continued exploration into the mechanisms behind itch and scratch may open the doors for new therapeutic interventions.
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9
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Kopruszinski CM, dos Reis RC, Rae GA, Chichorro JG. Blockade of peripheral endothelin receptors abolishes heat hyperalgesia and spontaneous nociceptive behavior in a rat model of facial cancer. Arch Oral Biol 2019; 97:231-237. [DOI: 10.1016/j.archoralbio.2018.10.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 10/30/2018] [Accepted: 10/31/2018] [Indexed: 12/27/2022]
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10
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Mahmoudi J, Mohaddes G, Erfani M, Sadigh-Eteghad S, Karimi P, Rajabi M, Reyhani-Rad S, Farajdokht F. Cerebrolysin attenuates hyperalgesia, photophobia, and neuroinflammation in a nitroglycerin-induced migraine model in rats. Brain Res Bull 2018; 140:197-204. [DOI: 10.1016/j.brainresbull.2018.05.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 05/03/2018] [Accepted: 05/08/2018] [Indexed: 02/07/2023]
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11
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Testing experience and environmental enrichment potentiated open-field habituation and grooming behaviour in rats. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2018.01.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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12
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Deseure K, Hans GH. Differential drug effects on spontaneous and evoked pain behavior in a model of trigeminal neuropathic pain. J Pain Res 2017; 10:279-286. [PMID: 28184169 PMCID: PMC5291328 DOI: 10.2147/jpr.s124526] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Baclofen and morphine have shown efficacy against mechanical allodynia after infraorbital nerve chronic constriction injury (IoN-CCI). No drug effects have yet been reported on spontaneous trigeminal neuropathic pain. It has been proposed that the directed face grooming behavior that also develops following IoN-CCI offers a measure of spontaneous trigeminal neuropathic pain. SUBJECTS AND METHODS We examined the effects of a continuous 1-week infusion of 30 mg/day carbamazepine (the first-line drug treatment for trigeminal neuralgia), 1.06 mg/day baclofen, 4.18 mg/day clomipramine, and 5 mg/day morphine on spontaneous and mechanically evoked pain behavior (ie, directed face grooming and von Frey testing) in IoN-CCI rats. RESULTS Isolated face grooming was significantly reduced in rats receiving carbamazepine and baclofen but not in clomipramine- or morphine-treated rats. All drugs showed significant antiallodynic effects; carbamazepine showed the strongest effects, whereas clomipramine had only minor efficacy. CONCLUSION The tested drugs have differential effects in the IoN-CCI model, and different neuropathological mechanisms may underlie the different somatosensory symptoms in this model. A mechanism-based approach may be needed to treat (trigeminal) neuropathic pain. The present data support IoN-CCI as a model of trigeminal neuralgia in which isolated face grooming is used as a measure of spontaneous neuropathic pain.
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Affiliation(s)
- K Deseure
- Department of Medicine, Laboratory for Pain Research, University of Antwerp, Wilrijk
| | - G H Hans
- Multidisciplinary Pain Center, Antwerp University Hospital, Edegem, Belgium
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13
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Tian B, Wang XL, Huang Y, Chen LH, Cheng RX, Zhou FM, Guo R, Li JC, Liu T. Peripheral and spinal 5-HT receptors participate in cholestatic itch and antinociception induced by bile duct ligation in rats. Sci Rep 2016; 6:36286. [PMID: 27824106 PMCID: PMC5099756 DOI: 10.1038/srep36286] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 10/13/2016] [Indexed: 12/19/2022] Open
Abstract
Although 5-HT has been implicated in cholestatic itch and antinociception, two common phenomena in patients with cholestatic disease, the roles of 5-HT receptor subtypes are unclear. Herein, we investigated the roles of 5-HT receptors in itch and antinociception associated with cholestasis, which was induced by common bile duct ligation (BDL) in rats. 5-HT-induced enhanced scratching and antinociception to mechanical and heat stimuli were demonstrated in BDL rats. 5-HT level in the skin and spinal cord was significantly increased in BDL rats. Quantitative RT-PCR analysis showed 5-HT1B, 5-HT1D, 5-HT2A, 5-HT3A, 5-HT5B, 5-HT6, and 5-HT7 were up-regulated in peripheral nervous system and 5-HT1A, 5-HT1F, 5-HT2B, and 5-HT3A were down-regulated in the spinal cord of BDL rats. Intradermal 5-HT2, 5-HT3, and 5-HT7 receptor agonists induced scratching in BDL rats, whereas 5-HT3 agonist did not induce scratching in sham rats. 5-HT1A, 5-HT2, 5-HT3, and 5-HT7 agonists or antagonists suppressed itch in BDL rats. 5-HT1A agonist attenuated, but 5-HT1A antagonist enhanced antinociception in BDL rats. 5-HT2 and 5-HT3 agonists or antagonists attenuated antinociception in BDL rats. Our data suggested peripheral and central 5-HT system dynamically participated in itch and antinociception under cholestasis condition and targeting 5-HT receptors may be an effective treatment for cholestatic itch.
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Affiliation(s)
- Bin Tian
- Department of General Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Xue-Long Wang
- Department of General Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Ya Huang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, 215123, China
| | - Li-Hua Chen
- Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Soochow University, Suzhou, 215123, China
| | - Ruo-Xiao Cheng
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, 215123, China
| | - Feng-Ming Zhou
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, 215123, China
| | - Ran Guo
- Department of Anesthesiology, The First Affiliated Hospital of Soochow University, Suzhou, 215006, China
| | - Jun-Cheng Li
- Department of General Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Tong Liu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, 215123, China
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14
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Akiyama T, Curtis E, Nguyen T, Carstens MI, Carstens E. Anatomical evidence of pruriceptive trigeminothalamic and trigeminoparabrachial projection neurons in mice. J Comp Neurol 2015; 524:244-56. [PMID: 26099199 DOI: 10.1002/cne.23839] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 06/05/2015] [Accepted: 06/08/2015] [Indexed: 11/06/2022]
Abstract
Itch is relayed to higher centers by projection neurons in the spinal and medullary dorsal horn. We employed a double-label method to map the ascending projections of pruriceptive and nociceptive trigeminal and spinal neurons. The retrograde tracer fluorogold (FG) was stereotaxically injected into the right thalamus or lateral parabrachial area (LPb) in mice. Seven days later, mice received intradermal (id) microinjection of histamine, chloroquine, capsaicin, or vehicle into the left cheek. Histamine, chloroquine, and capsaicin intradermally elicited similar distributions of Fos-positive neurons in the medial aspect of the superficial medullary and spinal dorsal horn from the trigeminal subnucleus caudalis to C2. Among neurons retrogradely labeled from the thalamus, 43%, 8%, and 22% were Fos-positive following id histamine, chloroquine, or capsaicin. Among the Fos-positive neurons following pruritic or capsaicin stimuli, ∼1-2% were retrogradely labeled with FG. Trigeminoparabrachial projection neurons exhibited a higher incidence of double labeling in the superficial dorsal horn. Among the neurons retrogradely labeled from LPb, 36%, 29%, and 33% were Fos positive following id injection of histamine, chloroquine, and capsaicin, respectively. Among Fos-positive neurons elicited by id histamine, chloroquine, and capsaicin, respectively, 3.7%, 4.3%, and 4.1% were retrogradely labeled from LPb. The present results indicate that, overall, relatively small subpopulations of pruriceptive and/or nociceptive neurons innervating the cheek project to thalamus or LPb. These results imply that the vast majority of pruritogen- and algogen-responsive spinal neurons are likely to function as interneurons relaying information to projection neurons and/or participating in segmental nocifensive circuits.
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Affiliation(s)
- Tasuku Akiyama
- Temple Itch Center, Department of Dermatology, Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, Pennsylvania, 19140
| | - Eric Curtis
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, California, 95616
| | - Tony Nguyen
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, California, 95616
| | - Mirela Iodi Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, California, 95616
| | - E Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, California, 95616
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15
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Itch elicited by intradermal injection of serotonin, intracisternal injection of morphine, and their synergistic interactions in rats. Neuroscience 2014; 274:119-27. [PMID: 24875173 DOI: 10.1016/j.neuroscience.2014.05.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 05/09/2014] [Accepted: 05/13/2014] [Indexed: 12/19/2022]
Abstract
We used the cheek model of itch and pain in rats to determine the dose-response relationships for intradermal injection of serotonin and α methylserotonin on scratching behavior. We also determined the dose-related effects of intracisternally injected morphine on scratching, effects that were greatly reduced by administration of the opiate antagonist naloxone. We then examined the interactions of intradermal injection of serotonin and intracisternal injection of morphine on scratching and found that the two procedures act synergistically to increase itch. These results suggest that morphine applied to the CNS is capable of producing itch and greatly increasing itch originating in the skin (hyperknesis).
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16
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Akiyama T, Nagamine M, Carstens MI, Carstens E. Behavioral model of itch, alloknesis, pain and allodynia in the lower hindlimb and correlative responses of lumbar dorsal horn neurons in the mouse. Neuroscience 2014; 266:38-46. [PMID: 24530451 DOI: 10.1016/j.neuroscience.2014.02.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 02/02/2014] [Accepted: 02/04/2014] [Indexed: 12/01/2022]
Abstract
We have further developed a behavioral model of itch and pain in the lower hindlimb (calf) originally reported by LaMotte et al. (2011) that allows comparisons with responses of lumbar dorsal horn neurons to pruritic and noxious stimuli. Intradermal (id) microinjection of the pruritogens histamine, SLIGRL-NH2 (agonist of PAR-2 and MrgprC11) and chloroquine (agonist of MrgprA3) into the calf of the lower limb elicited significant biting and a small amount of licking directed to the injection site, over a 30-min time course. Following id injection of histamine, low-threshold mechanical stimuli reliably elicited discrete episodes of biting (alloknesis) over a longer time course; significantly less alloknesis was observed following id injection of SLIGRL-NH2. Capsaicin injections elicited licking but little biting. Following id injection of capsaicin, low-threshold mechanical stimuli elicited discrete hindlimb flinches (allodynia) over a prolonged (>2h) time course. In single-unit recordings from superficial lumbar dorsal horn neurons, low-threshold mechanically evoked responses were significantly enhanced, accompanied by receptive field expansion, following id injection of histamine in histamine-responsive neurons. This was not observed in histamine-insensitive neurons, or following id injection of saline or SLIGRL-NH2, regardless of whether the latter activated the neuron or not. These results suggest that itch-responsive neurons are selectively sensitized by histamine but not SLIGRL-NH2 to account for alloknesis. The presently described "calf" model appears to distinguish between itch- and pain-related behavioral responses, and provides a basis to investigate lumbar spinal neural mechanisms underlying itch, alloknesis, pain and allodynia.
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Affiliation(s)
- T Akiyama
- University of California, Davis, Department of Neurobiology, Physiology & Behavior, 1 Shields Avenue, Davis, CA 95616, USA
| | - M Nagamine
- University of California, Davis, Department of Neurobiology, Physiology & Behavior, 1 Shields Avenue, Davis, CA 95616, USA
| | - M I Carstens
- University of California, Davis, Department of Neurobiology, Physiology & Behavior, 1 Shields Avenue, Davis, CA 95616, USA
| | - E Carstens
- University of California, Davis, Department of Neurobiology, Physiology & Behavior, 1 Shields Avenue, Davis, CA 95616, USA.
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17
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Abstract
The itch-scratch reflex serves as a protective mechanism in everyday life. However, chronic persistent itching can be devastating. Despite the clinical importance of the itch sensation, its mechanism remains elusive. In the past decade, substantial progress has been made to uncover the mystery of itching. Here, we review the molecules, cells, and circuits known to mediate the itch sensation, which, coupled with advances in understanding the pathophysiology of chronic itching conditions, will hopefully contribute to the development of new anti-itch therapies.
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Affiliation(s)
- Liang Han
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
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18
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Abstract
This paper is the thirty-fifth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2012 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
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19
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Abstract
While considerable effort has been made to investigate the neural mechanisms of pain, much less effort has been devoted to itch, at least until recently. However, itch is now gaining increasing recognition as a widespread and costly medical and socioeconomic issue. This is accompanied by increasing interest in the underlying neural mechanisms of itch, which has become a vibrant and rapidly-advancing field of research. The goal of the present forefront review is to describe the recent progress that has been made in our understanding of itch mechanisms.
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Affiliation(s)
- Tasuku Akiyama
- University of California, Davis, Department of Neurobiology, Physiology & Behavior, 1 Shields Avenue, Davis, CA 95616, United States
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20
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Nishida K, Takechi K, Akiyama T, Carstens MI, Carstens E. Scratching inhibits serotonin-evoked responses of rat dorsal horn neurons in a site- and state-dependent manner. Neuroscience 2013; 250:275-81. [PMID: 23867770 DOI: 10.1016/j.neuroscience.2013.07.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/30/2013] [Accepted: 07/04/2013] [Indexed: 10/26/2022]
Abstract
Scratching inhibits pruritogen-evoked responses of neurons in the superficial dorsal horn, implicating a spinal site for scratch inhibition of itch. We investigated if scratching differentially affects neurons depending on whether they are activated by itchy vs. painful stimuli, and if the degree of inhibition depends on the relative location of scratching. We recorded from rat lumbar dorsal horn neurons responsive to intradermal (id) microinjection of serotonin (5-hydroxytryptamine, 5-HT). During the response to 5-HT, scratch stimuli (3mm, 300 mN, 2 Hz, 20s) were delivered at the injection site within the mechanosensitive receptive field (on-site), or 4-30 mm away, outside of the receptive field (off-site). During off-site scratching, 5-HT-evoked firing was significantly attenuated followed by recovery. On-site scratching excited neurons, followed by a significant post-scratch decrease in 5-HT-evoked firing. Most neurons additionally responded to mustard oil (allyl isothiocyanate). Off-site scratching had no effect, while on-site scratching excited the neurons. These results indicate that scratching exerts a state-dependent inhibitory effect on responses of spinal neurons to pruritic but not algesic stimuli. Moreover, on-site scratching first excited neurons followed by inhibition, while off-site scratching immediately evoked the inhibition of pruritogen-evoked activity. This accounts for the suppression of itch by scratching at a distance from the site of the itchy stimulus.
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Affiliation(s)
- K Nishida
- Department of Anesthesiology and Resuscitology, Ehime University School of Medicine, Matsuyama, Japan
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21
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Moser HR, Giesler GJ. Itch and analgesia resulting from intrathecal application of morphine: contrasting effects on different populations of trigeminothalamic tract neurons. J Neurosci 2013; 33:6093-101. [PMID: 23554490 PMCID: PMC3668454 DOI: 10.1523/jneurosci.0216-13.2013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 02/22/2013] [Accepted: 02/23/2013] [Indexed: 11/21/2022] Open
Abstract
Intrathecal application of morphine is among the most powerful methods used to treat severe chronic pain. However, this approach commonly produces itch sufficiently severe that patients are forced to choose between relief of pain or itch. The neuronal populations responsible for processing and transmitting information underlying itch caused by intrathecal application of morphine have not been identified and characterized. We describe two populations of antidromically identified trigeminothalamic tract (VTT) neurons in anesthetized rats that are differentially affected by morphine and explain several aspects of opioid-induced itch and analgesia. We found that intrathecal application of morphine increased ongoing activity of itch-responsive VTT neurons. In addition, intrathecal application of morphine increased responses to pruritogens injected into the skin and greatly heightened responses to innocuous mechanical stimuli. In contrast, the ongoing activity and responses to noxious pinches in nociceptive VTT neurons were frequently inhibited by the same dose of morphine. These results reveal that i.t. application of morphine affects specific subpopulations of VTT neurons in ways that may produce itch, hyperknesis, alloknesis, and analgesia.
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Affiliation(s)
- Hannah R Moser
- Graduate Program in Neuroscience and Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, 55455, USA
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22
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Spradley JM, Davoodi A, Gee LB, Carstens MI, Carstens E. Differences in peripheral endocannabinoid modulation of scratching behavior in facial vs. spinally-innervated skin. Neuropharmacology 2012; 63:743-9. [PMID: 22683515 DOI: 10.1016/j.neuropharm.2012.05.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Revised: 05/09/2012] [Accepted: 05/14/2012] [Indexed: 11/29/2022]
Abstract
Cannabinoids suppress nocifensive behaviors in rodents. We presently investigated peripheral endocannabinoid modulation of itch- and pain-related behaviors elicited from facial vs. spinally-innervated skin of rats. Intradermal (id) injection of the pruritogen serotonin (5-HT) elicited significantly more hindlimb scratch bouts, and longer cumulative time scratching, when injected in the rostral back compared to the cheek. Pretreatment of skin with inhibitors of degrading enzymes for the endocannabinoids anandamide (URB597) or 2-arachidonoylglycerol (JZL184) significantly reduced scratching elicited by 5-HT in the rostral back. These effects were prevented by co-treatment with antagonists of the CB₁ (AM251) or CB₂ receptor (AM630), implicating both receptor subtypes in endocannabinoid suppression of scratching in spinally-innervated skin. Conversely, pretreatment with either enzyme inhibitor, or with AM630 alone, increased the number of scratch bouts elicited by id 5-HT injection in the cheek. Moreover, pretreatment with JZL184 also significantly increased pain-related forelimb wipes directed to the cheek following id injection of the algogen, allyl isothiocyanate (AITC; mustard oil). Thus, peripheral endocannabinoids have opposite effects on itch-related scratching behaviors in trigeminally- vs. spinally-innervated skin. These results suggest that increasing peripheral endocannabinoid levels represents a promising therapeutic approach to treat itch arising from the lower body, but caution that such treatment may not relieve, and may even exacerbate, itch and pain arising from trigeminally-innervated skin of the face or scalp.
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Affiliation(s)
- Jessica Marie Spradley
- Department of Neurobiology, Physiology & Behavior, University of California, One Shields Avenue, Davis, CA 95616-8519, USA
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