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Pearson J, Denley T, Blubaugh A, Kim SJ, Fogle JE, Leon R, Goss C, Banovic F. Characterisation of the pruritus responses and pruritic behaviours in an interleukin 31-induced canine model of pruritus. Vet Dermatol 2024; 35:296-304. [PMID: 38149639 DOI: 10.1111/vde.13231] [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: 01/24/2023] [Revised: 10/17/2023] [Accepted: 12/14/2023] [Indexed: 12/28/2023]
Abstract
BACKGROUND Intravenous administration of interleukin (IL)-31 in healthy dogs has been used as a model to assess antipruritic drugs. However, there is no known in-depth characterisation of pruritic behaviours, and the repeatability of the IL-31-induced pruritus in the individual dogs is currently unknown. OBJECTIVES To evaluate the immediate/delayed pruritus responses and the pruritic behaviours observed in the IL-31-induced pruritic model in healthy dogs after repeated IL-31 injections. ANIMALS Fifteen healthy laboratory beagles. METHODS All dogs were video-recorded for 270 min after two intravenous recombinant IL-31 injections (1.75 μg/kg) and vehicle (phosphate-buffered saline, control) injections, respectively; interventions were randomised and performed with a 2 week wash-out period. Two blinded investigators reviewed the pruritic behaviours of all video recordings. RESULTS Both canine IL-31 (IL-31_01, IL-31_02) injections significantly increased pruritic seconds and categorical minutes ('YES'/'NO' behaviour per discrete 1 min interval) in healthy dogs compared with both vehicle groups (Vehicle_01, Vehicle_02). The second intravenous canine IL-31 (IL-31_02) administered 14 days after the first IL-31 injection induced a significant increase in pruritic seconds (p = 0.021) and not pruritic categorical minutes (p = 0.231). An increase in pruritic seconds was observed in both IL-31 groups in the first 30 min post-administration, while there was no significant difference between IL-31 and vehicle groups. CONCLUSIONS AND CLINICAL RELEVANCE In conclusion, intravenous IL-31 reproducibly induces itch responses in dogs. Future evaluations of the canine IL-31 pruritic model should assess total pruritic behaviours in seconds rather than using a biased 'YES/NO' behaviour per 1 min scoring system.
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Affiliation(s)
- Jason Pearson
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Tara Denley
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Amanda Blubaugh
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Sujung Jun Kim
- Boehringer Ingelheim Animal Health, Athens, Georgia, USA
| | | | - Renato Leon
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Caleb Goss
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Frane Banovic
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
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2
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Koga K, Kobayashi K, Tsuda M, Pickering AE, Furue H. Anterior cingulate cross-hemispheric inhibition via the claustrum resolves painful sensory conflict. Commun Biol 2024; 7:330. [PMID: 38491200 PMCID: PMC10943010 DOI: 10.1038/s42003-024-06008-9] [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: 12/08/2022] [Accepted: 03/04/2024] [Indexed: 03/18/2024] Open
Abstract
The anterior cingulate cortex (ACC) responds to noxious and innocuous sensory inputs, and integrates them to coordinate appropriate behavioral reactions. However, the role of the projections of ACC neurons to subcortical areas and their influence on sensory processing are not fully investigated. Here, we identified that ACC neurons projecting to the contralateral claustrum (ACC→contraCLA) preferentially respond to contralateral mechanical sensory stimulation. These sensory responses were enhanced during attending behavior. Optogenetic activation of ACC→contraCLA neurons silenced pyramidal neurons in the contralateral ACC by recruiting local circuit fast-spiking interneuron activation via an excitatory relay in the CLA. This circuit activation suppressed withdrawal behavior to mechanical stimuli ipsilateral to the ACC→contraCLA neurons. Chemogenetic silencing showed that the cross-hemispheric circuit has an important role in the suppression of contralateral nociceptive behavior during sensory-driven attending behavior. Our findings identify a cross-hemispheric cortical-subcortical-cortical arc allowing the brain to give attentional priority to competing innocuous and noxious inputs.
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Affiliation(s)
- Keisuke Koga
- Department of Neurophysiology, Hyogo Medical University, Nishinomiya, Japan.
| | - Kenta Kobayashi
- Section of Viral Vector Development, National Institute for Physiological Sciences, Okazaki, Japan
| | - Makoto Tsuda
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Anthony E Pickering
- Anesthesia, Pain and Critical Care Research, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Hidemasa Furue
- Department of Neurophysiology, Hyogo Medical University, Nishinomiya, Japan.
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3
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Okutani H, Lo Vecchio S, Arendt-Nielsen L. Mechanisms and treatment of opioid-induced pruritus: Peripheral and central pathways. Eur J Pain 2024; 28:214-230. [PMID: 37650457 DOI: 10.1002/ejp.2180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 08/08/2023] [Accepted: 08/22/2023] [Indexed: 09/01/2023]
Abstract
BACKGROUND AND OBJECTIVE Pruritus (also known as itch) is defined as an unpleasant and irritating sensation of the skin that provokes an urge to scratch or rub. It is well known that opioid administration can cause pruritus, which is paradoxical as itch and pain share overlapping sensory pathways. Because opioids inhibit pain but can cause itching. Significant progress has been made to improve our understanding of the fundamental neurobiology of itch; however, much remains unknown about the mechanisms of opioid-induced pruritus. The prevention and treatment of opioid-induced pruritus remains a challenge in the field of pain management. The objective of this narrative review is to present and discuss the current body of literature and summarize the current understanding of the mechanisms underlying opioid-induced pruritus, and its relationship to analgesia, and possible treatment options. RESULTS The incidence of opioid-induced pruritus differs with different opioids and routes of administration, and the various mechanisms can be broadly divided into peripheral and central. Especially central mechanisms are intricate, even at the level of the spinal dorsal horn. There is evidence that opioid receptor antagonists and mixed agonist and antagonists, especially μ-opioid antagonists and κ-opioid agonists, are effective in relieving opioid-induced pruritus. Various treatments have been used for opioid-induced pruritus; however, most of them are controversial and have conflicting results. CONCLUSION The use of a multimodal analgesic treatment regimen combined with a mixed antagonist and κ agonists, especially μ-opioid antagonists, and κ-opioid agonists, seems to be the current best treatment modality for the management of opioid-induced pruritus and pain. SIGNIFICANCE Opioids remain the gold standard for the treatment of moderate to severe acute pain as well as cancer pain. It is well known that opioid-induced pruritus often does not respond to regular antipruritic treatment, thereby posing a challenge to clinicians in the field of pain management. We believe that our review makes a significant contribution to the literature, as studies on the mechanisms of opioid-induced pruritus and effective management strategies are crucial for the management of these patients.
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Affiliation(s)
- Hiroai Okutani
- Center for Neuroplasticity and Pain, SMI, Department of Health Science and Technology, School of Medicine, Aalborg University, Aalborg, Denmark
- Department of Anesthesiology and Pain Medicine, Hyogo Medical University, Nishinomiya, Hyogo, Japan
| | - Silvia Lo Vecchio
- Center for Neuroplasticity and Pain, SMI, Department of Health Science and Technology, School of Medicine, Aalborg University, Aalborg, Denmark
| | - Lars Arendt-Nielsen
- Center for Neuroplasticity and Pain, SMI, Department of Health Science and Technology, School of Medicine, Aalborg University, Aalborg, Denmark
- Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark
- Steno Diabetes Center North Denmark, Clinical Institute, Aalborg University Hospital, Aalborg, Denmark
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4
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Takanami K, Kuroiwa M, Ishikawa R, Imai Y, Oishi A, Hashino M, Shimoda Y, Sakamoto H, Koide T. Function of gastrin-releasing peptide receptors in ocular itch transmission in the mouse trigeminal sensory system. Front Mol Neurosci 2023; 16:1280024. [PMID: 38098939 PMCID: PMC10719851 DOI: 10.3389/fnmol.2023.1280024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Accepted: 11/03/2023] [Indexed: 12/17/2023] Open
Abstract
The prevalence of allergic conjunctivitis in itchy eyes has increased constantly worldwide owing to environmental pollution. Currently, anti-allergic and antihistaminic eye drops are used; however, there are many unknown aspects about the neural circuits that transmit itchy eyes. We focused on the gastrin-releasing peptide (GRP) and GRP receptor (GRPR), which are reportedly involved in itch transmission in the spinal somatosensory system, to determine whether the GRP system is involved in itch neurotransmission of the eyes in the trigeminal sensory system. First, the instillation of itch mediators, such as histamine (His) and non-histaminergic itch mediator chloroquine (CQ), exhibited concentration-dependent high levels of eye scratching behavior, with a significant sex differences observed in the case of His. Histological analysis revealed that His and CQ significantly increased the neural activity of GRPR-expressing neurons in the caudal part of the spinal trigeminal nucleus of the medulla oblongata in GRPR transgenic mice. We administered a GRPR antagonist or bombesin-saporin to ablate GRPR-expressing neurons, followed by His or CQ instillation, and observed a decrease in CQ-induced eye-scratching behavior in the toxin experiments. Intracisternal administration of neuromedin C (NMC), a GRPR agonist, resulted in dose-dependent excessive facial scratching behavior, despite the absence of an itch stimulus on the face. To our knowledge, this is the first study to demonstrate that non-histaminergic itchy eyes were transmitted centrally via GRPR-expressing neurons in the trigeminal sensory system, and that NMC in the medulla oblongata evoked facial itching.
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Affiliation(s)
- Keiko Takanami
- Mouse Genomics Resource Laboratory, National Institute of Genetics (NIG), Mishima, Japan
- Genetics, Research Organization of Information and Systems, Graduate University for Advanced Studies (SOKENDAI), Mishima, Japan
- Department of Environmental Health, Faculty of Human Life and Environmental Sciences, Nara Women’s University, Nara, Japan
| | - Masaya Kuroiwa
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Japan
| | - Ren Ishikawa
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Japan
| | - Yuji Imai
- Mouse Genomics Resource Laboratory, National Institute of Genetics (NIG), Mishima, Japan
- Technical Section, National Institute of Genetics, Mishima, Japan
| | - Akane Oishi
- Mouse Genomics Resource Laboratory, National Institute of Genetics (NIG), Mishima, Japan
- Technical Section, National Institute of Genetics, Mishima, Japan
| | - Midori Hashino
- Department of Environmental Health, Faculty of Human Life and Environmental Sciences, Nara Women’s University, Nara, Japan
| | - Yasushi Shimoda
- Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Japan
| | - Hirotaka Sakamoto
- Faculty of Environmental, Life, Natural Science and Technology, Ushimado Marine Institute (UMI), Okayama University, Okayama, Japan
- Department of Biology, Faculty of Environmental, Life, Natural Science, and Technology, Okayama University, Okayama, Japan
| | - Tsuyoshi Koide
- Mouse Genomics Resource Laboratory, National Institute of Genetics (NIG), Mishima, Japan
- Genetics, Research Organization of Information and Systems, Graduate University for Advanced Studies (SOKENDAI), Mishima, Japan
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5
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Pavlenko D, Todurga Seven Z, Bystrom L, Markan A, Verpile R, Ishida H, Akiyama T. Crisaborole Inhibits Itch and Pain by Preventing Neutrophil Infiltration in a Mouse Model of Atopic Dermatitis. Acta Derm Venereol 2023; 103:adv13382. [PMID: 37605895 PMCID: PMC10461178 DOI: 10.2340/actadv.v103.13382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 06/19/2023] [Indexed: 08/23/2023] Open
Abstract
Crisaborole, a phosphodiesterase 4 (PDE4) inhibitor, has been approved for the treatment of mild to moderate atopic dermatitis. Atopic dermatitis is often associated with increased pain. Using a mouse model, this study investigated whether crisaborole suppresses pain associated with atopic dermatitis and the potential mechanisms underlying it. The mouse model for atopic dermatitis was developed by repeatedly applying MC903. MC903-treated mice had increased spontaneous scratching (itch-related behaviour) and wiping behaviour (pain-related behaviour). Crisaborole was topically applied to the cheek skin of MC903-treated mice, and it reduced both itch- and pain-related behaviours in these mice. Immunofluorescence staining revealed that crisaborole reduced neutrophil infiltration and interaction of neutrophils with sensory neurones. Intradermal injection of S100A8/A9, proinflammatory neutrophil mediator, enhanced not only itch-related behaviours evoked by histamine or chloroquine, but also pain-related behaviours evoked by capsaicin. Calcium imaging of mouse dorsal root ganglion neurones revealed that pretreatment with S100A8/A9 significantly increased calcium responses to histamine and capsaicin, and the proportion of chloroquine-sensitive neurones. These findings suggest that the PDE4 inhibitor reduces itch and pain, in part by inhibiting infiltration of S100A8/A9-containing neutrophils in a mouse model of MC903-induced atopic dermatitis.
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Affiliation(s)
- Darya Pavlenko
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miami Itch Center, University of Miami Miller School of Medicine, Miami, USA
| | - Zeynep Todurga Seven
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miami Itch Center, University of Miami Miller School of Medicine, Miami, USA
- Department of Medical Pharmacology, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Lauren Bystrom
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miami Itch Center, University of Miami Miller School of Medicine, Miami, USA
| | - Anika Markan
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miami Itch Center, University of Miami Miller School of Medicine, Miami, USA
| | - Rebecca Verpile
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miami Itch Center, University of Miami Miller School of Medicine, Miami, USA
| | - Hirotake Ishida
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miami Itch Center, University of Miami Miller School of Medicine, Miami, USA
| | - Tasuku Akiyama
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, Miami Itch Center, University of Miami Miller School of Medicine, Miami, USA
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6
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Pearson J, Leon R, Starr H, Kim SJ, Fogle JE, Banovic F. Establishment of an Intradermal Canine IL-31-Induced Pruritus Model to Evaluate Therapeutic Candidates in Atopic Dermatitis. Vet Sci 2023; 10:vetsci10050329. [PMID: 37235412 DOI: 10.3390/vetsci10050329] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/07/2023] [Accepted: 04/11/2023] [Indexed: 05/28/2023] Open
Abstract
Pruritic models in healthy dogs utilizing intravenous administration of interleukin 31 (IL-31) bypass the "natural" itch sensation in AD, which is initiated by pruriceptive primary afferent neurons in the skin. This study aimed to evaluate the immediate/delayed pruritus responses and the pruritic behaviors observed in an intradermal IL-31-induced pruritic model of healthy dogs and the anti-pruritic effect of oclacitinib on said model. In Phase 1, all the dogs were randomized and video-recorded for 300 min after intradermal canine recombinant IL-31 injections (1.75 µg/kg) and vehicle (phosphate-buffered saline) injections. In Phase 2, all the dogs received oral oclacitinib (0.4-0.6 mg/kg, twice daily for 4 consecutive days and once daily on day 5), with the intradermal IL-31 injection performed on day 5. Two blinded investigators reviewed the pruritic behaviors in all the video recordings. Intradermal IL-31 administration to healthy dogs caused a significant increase in the total (p = 0.0052) and local (p = 0.0003) seconds of pruritic behavior compared to the vehicle control. Oral oclacitinib administration significantly reduced the total (p = 0.0011) and local (p = 0.0156) intradermal IL-31-induced pruritic seconds; there was no significant difference in pruritic seconds between the vehicle and oclacitinib within the IL-31 groups. Significant delayed pruritic responses at 150-300 min after IL-31 injections were observed, and intradermal IL-31 failed to induce acute itch (first 30 min). Intradermal injection of IL-31 induces delayed itch responses in dogs that are diminished by the effect of oclacitinib, an oral JAK inhibitor.
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Affiliation(s)
- Jason Pearson
- College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Renato Leon
- College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Haley Starr
- College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Sujung Jun Kim
- Boehringer Ingelheim Animal Health, Athens, GA 30601, USA
| | | | - Frane Banovic
- College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
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7
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Abstract
Transient receptor potential vanilloid type 1 (TRPV1) is a nonselective cation channel that is intensively expressed in the peripheral nerve system and involved in a variety of physiological and pathophysiological processes in mammals. Its activity is of great significance in transmitting pain or itch signals from peripheral sensory neurons to the central nervous system. The alteration or hypersensitivity of TRPV1 channel is well evidenced under various pathological conditions. Moreover, accumulative studies have revealed that TRPV1-expressing (TRPV1+) sensory neurons mediate the neuroimmune crosstalk by releasing neuropeptides to innervated tissues as well as immune cells. In the central projection, TRPV1+ terminals synapse with the secondary neurons for the transmission of pain and itch signalling. The intense involvement of TRPV1 and TRPV1+ neurons in pain and itch makes it a potential pharmaceutical target. Over decades, the basis of TRPV1 channel structure, the nature of its activity, and its modulation in pathological processes have been broadly studied and well documented. Herein, we highlight the role of TRPV1 and its associated neurons in sensing pain and itch. The fundamental understandings of TRPV1-involved nociception, pruriception, neurogenic inflammation, and cell-specific modulation will help bring out more effective strategies of TRPV1 modulation in treating pain- and itch-related diseases.
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8
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Qiao Z, Luo J, Tang YQ, Zhou Q, Qi H, Yin Z, Tang X, Zhu W, Zhang Y, Wei N, Wang K. Photosensitive and Photoswitchable TRPA1 Agonists Optically Control Pain through Channel Desensitization. J Med Chem 2021; 64:16282-16292. [PMID: 34662118 DOI: 10.1021/acs.jmedchem.1c01579] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Transient receptor potential ankyrin 1 (TRPA1) channel, as a nonselective ligand-gated cation channel robustly in dorsal root ganglion sensory neurons, is implicated in sensing noxious stimuli and nociceptive signaling. However, small-molecule tools targeting TRPA1 lack temporal and spatial resolution, limiting their use for validation of TRPA1 as a therapeutic target for pain. In our previous work, we found that 4,4'-(diazene-1,2-diyl)dianiline (AB1) is a photoswitchable TRPA1 agonist, but the poor water solubility and activity hinder its further development. Here, we report a series of specific and potent azobenzene-derived photoswitchable TRPA1 agonists (series 1 and 2) that enable optical control of the TRPA1 channel. Two representative compounds 1g and 2c can alleviate capsaicin-induced pain in the cheek model of mice through channel desensitization but not in TRPA1 knockout mice. Taken together, our findings demonstrate that photoswitchable TRPA1 agonists can be used as pharmacological tools for study of pain signaling.
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Affiliation(s)
- Zhen Qiao
- Departments of Pharmacology and Pharmaceutical Analysis, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China
| | - Jiajie Luo
- Departments of Pharmacology and Pharmaceutical Analysis, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China
| | - Yi-Quan Tang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200032, China
| | - Qiqi Zhou
- Department of Pharmacology, Qilu Medical University School of Pharmacy, Zibo 255300, China
| | - Hang Qi
- Departments of Pharmacology and Pharmaceutical Analysis, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China
| | - Zhengji Yin
- Departments of Pharmacology and Pharmaceutical Analysis, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China
| | - Xiaowen Tang
- Departments of Pharmacology and Pharmaceutical Analysis, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China
| | - Wei Zhu
- Departments of Pharmacology and Pharmaceutical Analysis, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China
| | - Yanru Zhang
- Departments of Pharmacology and Pharmaceutical Analysis, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China.,Institute of Innovative Drug, Qingdao University, Qingdao 266021, China
| | - Ningning Wei
- Departments of Pharmacology and Pharmaceutical Analysis, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China.,Institute of Innovative Drug, Qingdao University, Qingdao 266021, China
| | - KeWei Wang
- Departments of Pharmacology and Pharmaceutical Analysis, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China.,Institute of Innovative Drug, Qingdao University, Qingdao 266021, China
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9
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Abstract
Introduction: Cinnamaldehyde (CA) elicits itch sensation in humans. We investigated
if CA elicits scratching behavior in mice and determined the roles for
TRPV1, TRPA1, and TRPV4. Materials and Methods: Scratching behavior elicited by intradermal injection of CA was
assessed in wildtype (WT) mice and knockout (KO) mice lacking TRPV1, TRPA1,
TRPV4, or deficient in mast cells. We also assessed scratching and wet dog
shakes elicited by low-threshold mechanical stimulation of skin treated
topically with CA or vehicle. Using calcium imaging we tested if CA
activates dorsal root ganglion (DRG) neurons of each genotype. Results: Intradermal cheek injection of CA elicited dose-dependent hindlimb
scratch bouts, with fewer forelimb wipes and facial groom bouts that were
not dose-dependent. CA elicited significantly fewer scratch bouts in TRPV1
and TRPV4 KO mice, but not TRPA1KOs, compared with WTs. There were no sex
differences across genotypes. The histamine H1 antagonist cetirizine did not
affect CA-evoked scratching, which was normal in mast cell deficient mice,
indicating lack of histamine involvement. Scores for alloknesis were
significantly greater following topical application of CA compared with
vehicle. Post-CA alloknesis scores were significantly higher in TRPV4KOs of
both sexes and in female TRPV1 and TRPA1KOs, compared with WTs. Low
threshold mechanical stimuli also elicited significantly more wet dog shakes
in mice treated topically with 20% CA, with significantly fewer in TRPV1,
TRPA1, and TRPV4KOs compared with WTs. In calcium imaging studies, CA
excited 24% of WT DRG cells, significantly fewer (11.5%) in cells from
TRPV4KOs, and none in TRPA1KOs. Responses of cells of all genotypes
exhibited significant sensitization to repeated CA stimulation.
Sensitization was significantly enhanced by IL-4, which itself excited 16%
of WT DRG cells and none from TRPA1KOs. Discussion: The results indicate that TRPA1 is dispensable for CA-evoked
scratching, which depends partly on TRPV1 and TRPV4.
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10
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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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11
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Li HP, Wang XY, Chen C, Li JJ, Yu C, Lin LX, Yu ZE, Jin ZY, Zhu H, Xiang HC, Hu XF, Cao J, Jing XH, Li M. 100 Hz Electroacupuncture Alleviated Chronic Itch and GRPR Expression Through Activation of Kappa Opioid Receptors in Spinal Dorsal Horn. Front Neurosci 2021; 15:625471. [PMID: 33664646 PMCID: PMC7921323 DOI: 10.3389/fnins.2021.625471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/20/2021] [Indexed: 11/19/2022] Open
Abstract
Background Clinical studies have shown that electroacupuncture (EA) alleviates chronic itch. Gastrin-releasing peptide receptor (GRPR) and dynorphin (DYN) in the spinal dorsal horn positively or negatively regulate itch, respectively. However, which frequency of EA is effective on relieving chronic itch and reducing the expression of GRPR, whether DYN-A in the spinal cord is involved in the underlying mechanism of the antipruritus effect of EA remains unknown. Methods The mixture of acetone and diethyl ether (1:1) [designated as AEW (acetone/diethyl ether and water) treatment] was used to induce the dry skin model of chronic itch. EA was applied to Quchi (LI11) and Hegu (LI4). Western blot was used to detect the expression of GRPR and DYN-A. Immunofluorescence was used to detect the expression of DYN-A. Results The AEW administration induced remarkable spontaneous scratching, enhanced the expression of GRPR, and reduced the expression of DYN-A. Compared with the sham EA, 2 Hz EA, or 15 Hz EA group, 100 Hz EA was the most effective frequency for relieving chronic itch, reducing the expression of GRPR, and increasing the expression of DYN-A in the cervical dorsal horn. Furthermore, intraperitoneal injection of kappa opioid receptors (KORs) antagonist nor-Binaltorphimine dihydrochloride (nor-BNI) significantly reversed the effect of 100 Hz EA on the inhibition of both itching behavior and GRPR expression. Conclusion EA at 100 Hz is the most effective frequency that inhibits chronic itch and GRPR expression through activation of KORs in the spinal dorsal horn, which can effectively guide the clinical treatment and improve the antipruritic effect of acupuncture.
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Affiliation(s)
- Hong-Ping Li
- Department of Neurobiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiao-Yu Wang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Chao Chen
- Department of Neurobiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jing-Jing Li
- Department of Neurobiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chi Yu
- Department of Neurobiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Li-Xue Lin
- Department of Neurobiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zi-E Yu
- Department of Neurobiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhi-Yuan Jin
- Department of Neurobiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - He Zhu
- Department of Neurobiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hong-Chun Xiang
- Department of Neurobiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xue-Fei Hu
- Department of Neurobiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jie Cao
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiang-Hong Jing
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Man Li
- Department of Neurobiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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12
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Andoh T, Suzuki K, Konno M, Tsuneyama K, Kuraishi Y. Pharmacological Characterization of a Novel Mouse Model of Cholestatic Pruritus. Biol Pharm Bull 2020; 43:1111-1117. [PMID: 32612073 DOI: 10.1248/bpb.b20-00097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Patients with cholestatic liver diseases, such as primary biliary cirrhosis, usually suffer from pruritus. However, the pathogenesis of cholestatic pruritus is unclear, and there is no current effective treatment for it. In order to find a treatment for the condition, an appropriate mouse model should be developed. Therefore, here, we established a surgically-induced mouse model of cholestatic pruritus. The bile duct was ligated in order to block bile secretion from the anterior, right, and left lobes, with the exception of the caudate lobe. Serum levels of total bile acid increased after bile duct ligation (BDL). The spontaneous hind paw scratching was also increased in BDL mice. Spontaneous scratching was reduced in BDL mice by naloxone (µ-opioid receptor antagonist), U-50,488H (κ-opioid receptor agonist), and clonidine (α2-adrenoceptor agonist). Azelastine (H1 receptor antagonist with membrane-stabilizing activity) slightly reduced scratching. However, terfenadine (H1 receptor antagonist), methysergide (serotonin (5-HT)2 receptor antagonist), ondansetron (5-HT3 receptor antagonist), proteinase-activated receptor 2-neutralizing antibody, fluvoxamine (selective serotonin reuptake inhibitor), milnacipran (serotonin-noradrenalin reuptake inhibitor), and cyproheptadine (H1 and 5-HT2 receptor antagonist) did not affect scratching. These results suggested that partial obstruction of bile secretion in mice induced anti-histamine-resistant itching and that central opioid system is involved in cholestatic itching.
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Affiliation(s)
- Tsugunobu Andoh
- Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama.,Department of Pathological Pharmacology, College of Pharmacy, Kinjo Gakuin University
| | - Kazunari Suzuki
- Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
| | - Mitsuhiro Konno
- Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
| | - Koichi Tsuneyama
- Department of Pathology and Laboratory Medicine, Institute of Health Biosciences, Tokushima University Graduate School
| | - Yasushi Kuraishi
- Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
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13
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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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14
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Abstract
Itch is a topic to which everyone can relate. The physiological roles of itch are increasingly understood and appreciated. The pathophysiological consequences of itch impact quality of life as much as pain. These dynamics have led to increasingly deep dives into the mechanisms that underlie and contribute to the sensation of itch. When the prior review on the physiology of itching was published in this journal in 1941, itch was a black box of interest to a small number of neuroscientists and dermatologists. Itch is now appreciated as a complex and colorful Rubik's cube. Acute and chronic itch are being carefully scratched apart and reassembled by puzzle solvers across the biomedical spectrum. New mediators are being identified. Mechanisms blur boundaries of the circuitry that blend neuroscience and immunology. Measures involve psychophysics and behavioral psychology. The efforts associated with these approaches are positively impacting the care of itchy patients. There is now the potential to markedly alleviate chronic itch, a condition that does not end life, but often ruins it. We review the itch field and provide a current understanding of the pathophysiology of itch. Itch is a disease, not only a symptom of disease.
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Affiliation(s)
- Ferda Cevikbas
- Dermira, Inc., Menlo Park, California; and Harvard Medical School and the Cutaneous Biology Research Center at Massachusetts General Hospital, Charlestown, Massachusetts
| | - Ethan A Lerner
- Dermira, Inc., Menlo Park, California; and Harvard Medical School and the Cutaneous Biology Research Center at Massachusetts General Hospital, Charlestown, Massachusetts
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15
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Blubaugh A, Denley T, Banovic F. Characterization of a chloroquine-induced canine model of pruritus and skin inflammation. Vet Dermatol 2019; 31:128-133. [PMID: 31774226 DOI: 10.1111/vde.12818] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/03/2019] [Accepted: 10/14/2019] [Indexed: 11/30/2022]
Abstract
BACKGROUND Chloroquine (CQ) is a prototypical systemic and intradermal pruritogen for histamine-independent (nonhistaminergic) itch in mice and humans. The predictive validity of this model is poorly documented in dogs. HYPOTHESIS/OBJECTIVE To determine pruritogenic and inflammatory effects of systemic and i.d. CQ injections in healthy dogs. ANIMALS Ten healthy purpose-bred laboratory beagles. METHODS AND MATERIALS All dogs were randomized to receive i.d. (200 and 400 µg/site), intravenous (2 mg/kg) and subcutaneous (3 mg/kg) CQ injections. Dogs were video-recorded for 30 min after i.d. injections and for 300 min after i.v. and s.c. injections. Buffered saline injections served as controls for each route. Global wheal scores were evaluated at 30 min post-i.d. injection by a blinded investigator. RESULTS All dogs showed wheal and erythema at the CQ i.d. injection sites; global wheal scores of each CQ concentration were significantly increased compared to placebo (P ≤ 0.05). Blinded evaluation revealed no significant increase in generalized pruritic behaviour (pruritic seconds) after i.v. or s.c. administration of CQ. Intradermal injections induced mild localized acute pruritic behaviours at the site of injections at 200 µg (P = 0.06) and 400 µg (P = 0.27) CQ in dogs. CONCLUSION AND CLINICAL SIGNIFICANCE To the best of the authors' knowledge, this is the first report which shows that i.d. CQ injections may induce acute inflammation in healthy dogs. By contrast to the systemic CQ-induced pruritus reported previously in healthy mice and dogs, no significant pruritic behaviours were observed after CQ injection, regardless of the route of administration.
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Affiliation(s)
- Amanda Blubaugh
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 2200 College Station Road, Athens, GA, 30602, USA
| | - Tara Denley
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 2200 College Station Road, Athens, GA, 30602, USA
| | - Frane Banovic
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 2200 College Station Road, Athens, GA, 30602, USA
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16
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TRESK K + Channel Activity Regulates Trigeminal Nociception and Headache. eNeuro 2019; 6:ENEURO.0236-19.2019. [PMID: 31308053 PMCID: PMC6664143 DOI: 10.1523/eneuro.0236-19.2019] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 06/23/2019] [Indexed: 02/07/2023] Open
Abstract
Although TWIK-related spinal cord K+ (TRESK) channel is expressed in all primary afferent neurons in trigeminal ganglia (TG) and dorsal root ganglia (DRG), whether TRESK activity regulates trigeminal pain processing is still not established. Dominant-negative TRESK mutations are associated with migraine but not with other types of pain in humans, suggesting that genetic TRESK dysfunction preferentially affects the generation of trigeminal pain, especially headache. Using TRESK global knock-out mice as a model system, we found that loss of TRESK in all TG neurons selectively increased the intrinsic excitability of small-diameter nociceptors, especially those that do not bind to isolectin B4 (IB4-). Similarly, loss of TRESK resulted in hyper-excitation of the small IB4- dural afferent neurons but not those that bind to IB4 (IB4+). Compared with wild-type littermates, both male and female TRESK knock-out mice exhibited more robust trigeminal nociceptive behaviors, including headache-related behaviors, whereas their body and visceral pain responses were normal. Interestingly, neither the total persistent outward current nor the intrinsic excitability was altered in adult TRESK knock-out DRG neurons, which may explain why genetic TRESK dysfunction is not associated with body and/or visceral pain in humans. We reveal for the first time that, among all primary afferent neurons, TG nociceptors are the most vulnerable to the genetic loss of TRESK. Our findings indicate that endogenous TRESK activity regulates trigeminal nociception, likely through controlling the intrinsic excitability of TG nociceptors. Importantly, we provide evidence that genetic loss of TRESK significantly increases the likelihood of developing headache.
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17
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Nakahara T, Kido-Nakahara M, Furue M. Potential Role of Endothelin-1 in Atopic Dermatitis. CURRENT TREATMENT OPTIONS IN ALLERGY 2019. [DOI: 10.1007/s40521-019-00206-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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Banovic F, Denley T, Blubaugh A. Dose-dependent pruritogenic and inflammatory effects of intradermal injections of histamine, compound 48/80 and anti-canine IgE in healthy dogs. Vet Dermatol 2019; 30:325-e91. [PMID: 31038263 DOI: 10.1111/vde.12754] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND Scratching behaviours associated with intradermal (i.d.) injection of pruritogens such as histamine and compound 48/80 into the skin of mice and humans is the commonly used model to advance itch research and drug development. The predictive validity of this model is poorly documented in dogs. OBJECTIVES To evaluate the dose-dependent effects of pruritogenic substances, each with a different mechanism of action, in healthy dogs. ANIMALS Ten healthy laboratory beagles. METHODS AND MATERIALS All dogs were video-recorded for 30 min post-injection (mpi) of i.d. goat anti-canine IgE (4 and 25 μg/site), histamine and compound 48/80 (50, 100, 200, 400 μg/site); two buffered saline injections served as controls. Two blinded investigators reviewed the pruritic behaviours of all video recordings. Global wheal scores were evaluated at 30 min by a blinded investigator. RESULTS All dogs showed wheal and erythema at the pruritogen injection site; global wheal scores at 30 min of each substance significantly increased at all concentrations compared to control (P ≤ 0.05). A blinded evaluation revealed that all pruritogens induced mild acute pruritic behaviours at the site of injection. There was no injection site pain seen in any dog. Compared to controls, injections of pruritogens did not significantly affect the pruritic seconds or occurrence of pruritic episodes for any of the substances. CONCLUSIONS AND CLINICAL SIGNIFICANCE These preliminary results suggest that i.d. injections of the studied pruritogens can induce cutaneous wheal and flare response in healthy dogs; but inconsistencies occur in the induction of itch, even with the different concentrations of pruritogens.
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Affiliation(s)
- Frane Banovic
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 2200 College Station Road, Athens, GA, 30602, USA
| | - Tara Denley
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 2200 College Station Road, Athens, GA, 30602, USA
| | - Amanda Blubaugh
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 2200 College Station Road, Athens, GA, 30602, USA
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19
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Li S, Andoh T, Zhang Q, Uta D, Kuraishi Y. β2-Microglobulin, interleukin-31, and arachidonic acid metabolites (leukotriene B4 and thromboxane A2) are involved in chronic renal failure-associated itch-associated responses in mice. Eur J Pharmacol 2019; 847:19-25. [DOI: 10.1016/j.ejphar.2019.01.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 12/26/2018] [Accepted: 01/14/2019] [Indexed: 12/20/2022]
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20
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A Subpopulation of Amygdala Neurons Mediates the Affective Component of Itch. J Neurosci 2019; 39:3345-3356. [PMID: 30819800 DOI: 10.1523/jneurosci.2759-18.2019] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 02/19/2019] [Accepted: 02/21/2019] [Indexed: 01/01/2023] Open
Abstract
Itch consists of both sensory and affective components. For chronic itch patients, the affective component of itch affects both quality of life (leading to psychological comorbidities) and disease prognosis (by promoting scratching of itchy skin). We found that acute itch stimuli, such as histamine, induced anxiety-like behavior and increased activity (c-Fos expression) in the amygdala in adult male C57BL/6 mice. Itch stimuli also increased activity in projection areas to the amygdala, suggesting that these regions form a circuit for affective itch processing. Electrophysiological characterization of histamine-responsive amygdala neurons showed that this population was active on a behaviorally relevant timescale and partially overlapped with pain signaling. Selective optogenetic activation of histamine-responsive amygdala neurons in adult male and female Fos:CreERT2;R26Ai14 mice using the Targeted Recombination in Active Populations system enhanced both scratching and anxiety-like behavior. These results highlight the importance of itch-responsive amygdala neurons in modulating itch-related affect and behavior.SIGNIFICANCE STATEMENT The sensation of itch includes an affective component that leads to stress and anxiety in chronic itch patients. We investigated the neuronal basis of affective itch in mice, with a focus on the amygdala, the key brain region for the generation of anxiety. A subpopulation of amygdala neurons responded to itch stimuli such as histamine. Optogenetic activation of histamine-responsive amygdala neurons affected both scratching and anxiety-like behavior. Therefore, this population appears to be important for mediating the affective component of itch.
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21
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Shiratori-Hayashi M, Hasegawa A, Toyonaga H, Andoh T, Nakahara T, Kido-Nakahara M, Furue M, Kuraishi Y, Inoue K, Dong X, Tsuda M. Role of P2X3 receptors in scratching behavior in mouse models. J Allergy Clin Immunol 2018; 143:1252-1254.e8. [PMID: 30452925 DOI: 10.1016/j.jaci.2018.10.053] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 10/11/2018] [Accepted: 10/19/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Miho Shiratori-Hayashi
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Ayumi Hasegawa
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Honami Toyonaga
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Tsugunobu Andoh
- Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Takeshi Nakahara
- Department of Dermatology, Graduate School of Medicine, Kyushu University, Fukuoka, Japan
| | - Makiko Kido-Nakahara
- Department of Dermatology, Graduate School of Medicine, Kyushu University, Fukuoka, Japan
| | - Masutaka Furue
- Department of Dermatology, Graduate School of Medicine, Kyushu University, Fukuoka, Japan
| | - Yasushi Kuraishi
- Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Kazuhide Inoue
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience and the Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Md
| | - Makoto Tsuda
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
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22
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Itch induced by peripheral mu opioid receptors is dependent on TRPV1-expressing neurons and alleviated by channel activation. Sci Rep 2018; 8:15551. [PMID: 30341332 PMCID: PMC6195532 DOI: 10.1038/s41598-018-33620-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 09/28/2018] [Indexed: 12/16/2022] Open
Abstract
Opioids remain the gold standard for the treatment of moderate to severe pain. However, their analgesic properties come with important side effects, including pruritus, which occurs frequently after systemic or neuraxial administration. Although part of the opioid-induced itch is mediated centrally, recent evidence shows that the opioid receptor system in the skin also modulates itch. The goal of our study was to identify the peripherally located transducer mechanisms involved in opioid-induced pruritus. Scratching behaviors in response to an intradermal injection of the mu-opioid receptor (MOR) agonist [D-Ala2, N-MePhe4, Gly-ol]-enkephalin (DAMGO) was quantified in mast cell-, PAR2- and TRPV1-deficient mice or following ablation of TRPV1+ sensory neurons. We found that mast cells−/−, PAR-2−/−, or TRPV1−/− mice still exhibit DAMGO-induced itch responses. However, we show that ablation of TRPV1+ neurons or acute TRPV1 activation by capsaicin abolishes DAMGO-induced itch. Overall, our work shows that peripheral DAMGO-induced itch is dependent on the presence of TRPV1-expressing pruriceptors, but not the TRPV1 channel itself. Activation of these fibers by capsaicin prevents the opioid-induced itch.
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23
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Esancy K, Condon L, Feng J, Kimball C, Curtright A, Dhaka A. A zebrafish and mouse model for selective pruritus via direct activation of TRPA1. eLife 2018; 7:32036. [PMID: 29561265 PMCID: PMC5912907 DOI: 10.7554/elife.32036] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 03/19/2018] [Indexed: 11/13/2022] Open
Abstract
Little is known about the capacity of lower vertebrates to experience itch. A screen of itch-inducing compounds (pruritogens) in zebrafish larvae yielded a single pruritogen, the TLR7 agonist imiquimod, that elicited a somatosensory neuron response. Imiquimod induced itch-like behaviors in zebrafish distinct from those induced by the noxious TRPA1 agonist, allyl isothiocyanate. In the zebrafish, imiquimod-evoked somatosensory neuronal responses and behaviors were entirely dependent upon TRPA1, while in the mouse TRPA1 was required for the direct activation of somatosensory neurons and partially responsible for behaviors elicited by this pruritogen. Imiquimod was found to be a direct but weak TRPA1 agonist that activated a subset of TRPA1 expressing neurons. Imiquimod-responsive TRPA1 expressing neurons were significantly more sensitive to noxious stimuli than other TRPA1 expressing neurons. Together, these results suggest a model for selective itch via activation of a specialized subpopulation of somatosensory neurons with a heightened sensitivity to noxious stimuli. Itch is a common and uncomfortable sensation that creates a strong desire to scratch. This mechanism may have evolved so animals can remove harmful parasites or substances from themselves. Feelings like touch, pain, and itch arise when stimuli such as mechanical pressure, temperature, or chemicals activate groups of specialized neurons in the skin. This response takes place when certain proteins – or receptors – at the surface of the neurons are stimulated. For instance, TRP ion channels such as TRPA1 play an important role in both the itch and pain responses. In mammals, directly activating these channels elicits pain. Itch is felt when itch responsive receptors are activated on a distinct set of neurons, which in turn activate TRP receptors. Although these processes have been well-studied in mammals, little is known about the existence of itch sensation in other animals. To explore this, Esancy, Condon, Feng et al. exposed zebrafish to chemicals that induce itch in mammals, and found that imiquimod, a medicine used to treat certain skin conditions, can elicit itch in fish. When this chemical was injected into the lips of a fish, the animal rubbed them against the walls of its tank, akin to scratching an itch. Further experiments showed that imiquimod directly activated the pain-sensing ion channel TRPA1. In fact, this receptor was essential to the ‘scratching’ behavior: fish genetically engineered to lack TRPA1 did not react to the drug. Fluorescent proteins were then used to track when the neurons that carry TRPA1 were activated.This revealed that, in the skin of zebrafish, there are at least two functionally distinct populations neurons that express TRPA1. One population, whose activation is associated with the animal ‘scratching’, responds even when TRPA1 receives a low level of stimulation. The other population is less sensitive: it responds only to high-intensity stimuli and is associated with a pain response such as freezing and slower movements. Further experiments in the mouse suggest that this mechanism is present in mammals as well. This coding strategy explains how pain and itch can be experienced when the same receptors are being activated. Studying how animals like fish experience itch gives an insight into how detecting these sensations could have evolved. In turn, understanding this mechanism at the molecular and cellular levels may help find new ways to design better treatments for itch and pain disorders.
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Affiliation(s)
- Kali Esancy
- Department of Biological Structure, University of Washington, Seattle, United States.,Graduate Program in Neuroscience, University of Washington, Seattle, United States
| | - Logan Condon
- Department of Biological Structure, University of Washington, Seattle, United States
| | - Jing Feng
- Center for the Study of Itch, Washington University, St. Louis, United States
| | - Corinna Kimball
- Department of Biological Structure, University of Washington, Seattle, United States
| | - Andrew Curtright
- Department of Biological Structure, University of Washington, Seattle, United States
| | - Ajay Dhaka
- Department of Biological Structure, University of Washington, Seattle, United States.,Graduate Program in Neuroscience, University of Washington, Seattle, United States
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24
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Abstract
Itch is an unpleasant sensation that initiates scratching behavior. The itch-scratch reaction is a complex phenomenon that implicates supraspinal structures required for regulation of sensory, emotional, cognitive, and motivational aspects. However, the central mechanisms underlying the processing of itch and the interplay of the supraspinal regions and spinal cord in regulating itch-scratch processes are poorly understood. Here, we have shown that the neural projections from anterior cingulate cortex (ACC) to dorsal medial striatum (DMS) constitute a critical circuit element for regulating itch-related behaviors in the brains of male C57BL/6J mice. Moreover, we demonstrate that ACC-DMS projections selectively modulate histaminergic, but not nonhistaminergic, itch-related behavior. Furthermore, photoactivation of ACC-DMS projections has also no significant effects on pain behavior induced by thermal, mechanical, and chemical stimuli except for a relief on inflammatory pain evoked by formalin and complete Freund's adjuvant. We further demonstrate that the dorsal spinal cord exerts an inhibitory effect on itch signal from ACC-DMS projections through B5-I neurons, which represent a population of spinal inhibitory interneurons that mediate the inhibition of itch. Therefore, this study presents the first evidence that the ACC-DMS projections modulate histaminergic itch-related behavior and reveals an interplay between the supraspinal and spinal levels in histaminergic itch regulation.SIGNIFICANCE STATEMENT This study reveals that the projections from anterior cingulate cortex (ACC) to dorsal medial striatum (DMS) constitute a supraspinal circuit for modulation of histaminergic, but not nonhistaminergic, itch. Manipulation of ACC-DMS projections has no effect on acute pain sensation. Furthermore, the dorsal spinal cord exerts an inhibitory effect on itch signal from ACC-DMS projections through B5-I neurons. Understanding the supraspinal itch circuits is of great significance in the development of new therapies for chronic itch-related intractable diseases.
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25
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Elliott P, G’Sell M, Snyder LM, Ross SE, Ventura V. Automated acoustic detection of mouse scratching. PLoS One 2017; 12:e0179662. [PMID: 28678797 PMCID: PMC5497976 DOI: 10.1371/journal.pone.0179662] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 06/01/2017] [Indexed: 11/19/2022] Open
Abstract
Itch is an aversive somatic sense that elicits the desire to scratch. In animal models of itch, scratching behavior is frequently used as a proxy for itch, and this behavior is typically assessed through visual quantification. However, manual scoring of videos has numerous limitations, underscoring the need for an automated approach. Here, we propose a novel automated method for acoustic detection of mouse scratching. Using this approach, we show that chloroquine-induced scratching behavior in C57BL/6 mice can be quantified with reasonable accuracy (85% sensitivity, 75% positive predictive value). This report is the first method to apply supervised learning techniques to automate acoustic scratch detection.
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Affiliation(s)
- Peter Elliott
- Department of Statistics, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Max G’Sell
- Department of Statistics, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Lindsey M. Snyder
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States of America
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Sarah E. Ross
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States of America
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Valérie Ventura
- Department of Statistics, Carnegie Mellon University, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States of America
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Mueller SM, Hogg S, Mueller JM, McKie S, Itin P, Reinhardt J, Griffiths CE, Kleyn CE. Functional magnetic resonance imaging in dermatology: The skin, the brain and the invisible. Exp Dermatol 2017; 26:845-853. [DOI: 10.1111/exd.13305] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2017] [Indexed: 01/05/2023]
Affiliation(s)
- Simon M. Mueller
- Department of Dermatology; University Hospital Basel; Basel Switzerland
- Dermatology Centre; The Manchester Academic Health Science Centre; The University of Manchester; Manchester UK
| | - Samuel Hogg
- Department of Dermatology; University Hospital Basel; Basel Switzerland
| | - Jannis M. Mueller
- Department of Neurology; Kantonsspital Muensterlingen; Muensterlingen Switzerland
| | - Shane McKie
- Neuroscience and Psychiatry Unit; The Manchester Academic Health Science Centre; The University of Manchester; Manchester UK
| | - Peter Itin
- Dermatology Centre; The Manchester Academic Health Science Centre; The University of Manchester; Manchester UK
| | - Julia Reinhardt
- Division of Diagnostic & Interventional Neuroradiology; University Hospital Basel; Basel Switzerland
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Abstract
Migraine and other primary headache disorders affect a large population and cause debilitating pain. Establishing animal models that display behavioral correlates of long-lasting and ongoing headache, the most common and disabling symptom of migraine, is vital for the elucidation of disease mechanisms and identification of drug targets. We have developed a mouse model of headache, using dural application of capsaicin along with a mixture of inflammatory mediators (IScap) to simulate the induction of a headache episode. This elicited intermittent head-directed wiping and scratching as well as the phosphorylation of c-Jun N-terminal kinase in trigeminal ganglion neurons. Interestingly, dural application of IScap preferentially induced FOS protein expression in the excitatory but not inhibitory cervical/medullary dorsal horn neurons. The duration of IScap-induced behavior and the number of FOS-positive neurons correlated positively in individual mice; both were reduced to the control level by the pretreatment of antimigraine drug sumatriptan. Dural application of CGRP(8-37), the calcitonin gene-related peptide (CGRP) receptor antagonist, also effectively blocked IScap-induced behavior, which suggests that the release of endogenous CGRP in the dura is necessary for IScap-induced nociception. These data suggest that dural IScap-induced nocifensive behavior in mice may be mechanistically related to the ongoing headache in humans. In addition, dural application of IScap increased resting time in female mice. Taken together, we present the first detailed study using dural application of IScap in mice. This headache model can be applied to genetically modified mice to facilitate research on the mechanisms and therapeutic targets for migraine headache.
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Hoeck EA, Marker JB, Gazerani P, H. Andersen H, Arendt-Nielsen L. Preclinical and human surrogate models of itch. Exp Dermatol 2016; 25:750-7. [DOI: 10.1111/exd.13078] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Emil A. Hoeck
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
| | - Jens B. Marker
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
| | - Parisa Gazerani
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
| | - Hjalte H. Andersen
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
| | - Lars Arendt-Nielsen
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
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Andersen HH, Imai Y, Petersen KK, Koenig J, Elberling J, Arendt-Nielsen L. Conditioning pain stimulation does not affect itch induced by intra-epidermal histamine pricks but aggravates neurogenic inflammation in healthy volunteers. Somatosens Mot Res 2016; 33:49-60. [DOI: 10.3109/08990220.2016.1173535] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- H. H. Andersen
- SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Y. Imai
- SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
- Clinical Development Department, Clinical Department Center, Asahi Kasei Pharma Corporation, Tokyo, Japan
| | - K. K. Petersen
- SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - J. Koenig
- Department of Psychology, The Ohio State University, Columbus, Ohio, USA
- Section for Translational Psychobiology in Child and Adolescent Psychiatry, Department of Child and Adolescent Psychiatry, Centre for Psychosocial Medicine, University of Heidelberg, Heidelberg, Germany
| | - J. Elberling
- The Allergy Clinic, Copenhagen University Hospital, Gentofte, Copenhagen, Denmark
| | - L. Arendt-Nielsen
- SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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GABAA Receptors in the Central Nucleus of the Amygdala Are Involved in Pain- and Itch-Related Responses. THE JOURNAL OF PAIN 2016; 17:181-9. [DOI: 10.1016/j.jpain.2015.10.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 10/09/2015] [Accepted: 10/17/2015] [Indexed: 11/20/2022]
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Assessment of Itch and Pain in Animal Models and Human Subjects. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 904:1-22. [PMID: 26900059 DOI: 10.1007/978-94-017-7537-3_1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
For the past century, scientists have developed a variety of methods to evaluate itch and pain in both animal models and human subjects to throw light on some of the most important pathways mediating these unpleasant sensations. Discoveries in the mechanisms underlying itch and pain in both physiological and pathological conditions relied greatly upon these studies and may eventually lead to the discovery of new therapeutics. However, it was a much more complicated job to access itch and pain in animal models than in human subjects due to the subjective nature of these sensations. The results could be contradictory or even misleading when applying different methodologies in animal models, especially under pathological conditions with a mixed sensation of itch and pain. This chapter introduces and evaluates some of the classical and newly designed methodologies to access the sensation of itch and pain in animal models as well as human subjects.
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Shimizu K, Andoh T, Yoshihisa Y, Shimizu T. Histamine Released from Epidermal Keratinocytes Plays a Role in α-Melanocyte–Stimulating Hormone-Induced Itching in Mice. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:3003-10. [DOI: 10.1016/j.ajpath.2015.07.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 07/01/2015] [Accepted: 07/14/2015] [Indexed: 10/23/2022]
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Patricio ES, Costa R, Figueiredo CP, Gers-Barlag K, Bicca MA, Manjavachi MN, Segat GC, Gentry C, Luiz AP, Fernandes ES, Cunha TM, Bevan S, Calixto JB. Mechanisms Underlying the Scratching Behavior Induced by the Activation of Proteinase-Activated Receptor-4 in Mice. J Invest Dermatol 2015; 135:2484-2491. [DOI: 10.1038/jid.2015.183] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 04/20/2015] [Accepted: 04/27/2015] [Indexed: 02/08/2023]
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Peng Z, Li WG, Huang C, Jiang YM, Wang X, Zhu MX, Cheng X, Xu TL. ASIC3 Mediates Itch Sensation in Response to Coincident Stimulation by Acid and Nonproton Ligand. Cell Rep 2015; 13:387-98. [PMID: 26440887 DOI: 10.1016/j.celrep.2015.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 07/20/2015] [Accepted: 08/31/2015] [Indexed: 11/25/2022] Open
Abstract
The regulation and mechanisms underlying itch sensation are complex. Here, we report a role for acid-sensing ion channel 3 (ASIC3) in mediating itch evoked by certain pruritogens during tissue acidosis. Co-administration of acid with Ser-Leu-Ile-Gly-Arg-Leu-NH2 (SL-NH2) increased scratching behavior in wild-type, but not ASIC3-null, mice, implicating the channel in coincident detection of acidosis and pruritogens. Mechanistically, SL-NH2 slowed desensitization of proton-evoked currents by targeting the previously identified nonproton ligand-sensing domain located in the extracellular region of ASIC3 channels in primary sensory neurons. Ablation of the ASIC3 gene reduced dry-skin-induced scratching behavior and pathological changes under conditions with concomitant inflammation. Taken together, our data suggest that ASIC3 mediates itch sensation via coincident detection of acidosis and nonproton ligands that act at the nonproton ligand-sensing domain of the channel.
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Affiliation(s)
- Zhong Peng
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Wei-Guang Li
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Chen Huang
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yi-Ming Jiang
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xiang Wang
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Michael Xi Zhu
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Xiaoyang Cheng
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
| | - Tian-Le Xu
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
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Akiyama T, Nagamine M, Davoodi A, Iodi Carstens M, Cevikbas F, Steinhoff M, Carstens E. Intradermal endothelin-1 excites bombesin-responsive superficial dorsal horn neurons in the mouse. J Neurophysiol 2015; 114:2528-34. [PMID: 26311187 DOI: 10.1152/jn.00723.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 08/24/2015] [Indexed: 01/21/2023] Open
Abstract
Endothelin-1 (ET-1) has been implicated in nonhistaminergic itch. Here we used electrophysiological methods to investigate whether mouse superficial dorsal horn neurons respond to intradermal (id) injection of ET-1 and whether ET-1-sensitive neurons additionally respond to other pruritic and algesic stimuli or spinal superfusion of bombesin, a homolog of gastrin-releasing peptide (GRP) that excites spinal itch-signaling neurons. Single-unit recordings were made from lumbar dorsal horn neurons in pentobarbital-anesthetized C57BL/6 mice. We searched for units that exhibited elevated firing after id injection of ET-1 (1 μg/μl). Responsive units were further tested with mechanical stimuli, bombesin (spinal superfusion, 200 μg·ml(-1)·min(-1)), heating, cooling, and additional chemicals [histamine, chloroquine, allyl isothiocyanate (AITC), capsaicin]. Of 40 ET-1-responsive units, 48% responded to brush and pinch [wide dynamic range (WDR)] and 52% to pinch only [high threshold (HT)]. Ninety-three percent responded to noxious heat, 50% to cooling, and >70% to histamine, chloroquine, AITC, and capsaicin. Fifty-seven percent responded to bombesin, suggesting that they participate in spinal itch transmission. That most ET-1-sensitive spinal neurons also responded to pruritic and algesic stimuli is consistent with previous studies of pruritogen-responsive dorsal horn neurons. We previously hypothesized that pruritogen-sensitive neurons signal itch. The observation that ET-1 activates nociceptive neurons suggests that both itch and pain signals may be generated by ET-1 to result in simultaneous sensations of itch and pain, consistent with observations that ET-1 elicits both itch- and pain-related behaviors in animals and burning itch sensations in humans.
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Affiliation(s)
- T Akiyama
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California
| | - M Nagamine
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California
| | - A Davoodi
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California
| | - M Iodi Carstens
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California
| | - F Cevikbas
- Departments of Dermatology and Surgery, University of California, San Francisco, California; and
| | - M Steinhoff
- Department of Dermatology and Charles Institute for Translational Dermatology, University College Dublin, Dublin, Ireland
| | - E Carstens
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California;
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Protease-Activated Receptor 2 Antagonist Potentiates Analgesic Effects of Systemic Morphine in a Rat Model of Bone Cancer Pain. Reg Anesth Pain Med 2015; 40:158-65. [DOI: 10.1097/aap.0000000000000211] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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37
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Involvement of leukotriene B4 in dermatophyte-related itch in mice. Pharmacol Rep 2014; 66:699-703. [PMID: 24948074 DOI: 10.1016/j.pharep.2014.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 12/27/2013] [Accepted: 01/03/2014] [Indexed: 11/20/2022]
Abstract
BACKGROUND Proteinase-activated receptor-2 (PAR2) is involved in dermatophyte-induced scratching and leukotriene B4 (LTB4) release from keratinocytes. We investigated whether PAR2-mediated LTB4 production is involved in dermatophyte-induced scratching. METHODS Dermatophyte extract was injected intradermally and scratching was observed in mice. LTB4 was determined by enzyme immunoassay. RESULTS Dermatophyte extract-induced scratching was inhibited by zileuton (5-lipoxygenase inhibitor), ONO-4057 (LTB4 antagonist), FSLLRY-NH2 (PAR2 antagonist), and anti-PAR2 antibody. Dermatophyte extract injection increased the cutaneous content of LTB4, which was inhibited by zileuton and FSLLRY-NH2. CONCLUSION These results suggest the involvement of LTB4 in dermatophyte-associated itch. LTB4 production might be due to PAR2 stimulation in the skin.
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Kardon AP, Polgár E, Hachisuka J, Snyder LM, Cameron D, Savage S, Cai X, Karnup S, Fan CR, Hemenway GM, Bernard CS, Schwartz ES, Nagase H, Schwarzer C, Watanabe M, Furuta T, Kaneko T, Koerber HR, Todd AJ, Ross SE. Dynorphin acts as a neuromodulator to inhibit itch in the dorsal horn of the spinal cord. Neuron 2014; 82:573-86. [PMID: 24726382 PMCID: PMC4022838 DOI: 10.1016/j.neuron.2014.02.046] [Citation(s) in RCA: 240] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2014] [Indexed: 12/15/2022]
Abstract
Menthol and other counterstimuli relieve itch, resulting in an antipruritic state that persists for minutes to hours. However, the neural basis for this effect is unclear, and the underlying neuromodulatory mechanisms are unknown. Previous studies revealed that Bhlhb5−/− mice, which lack a specific population of spinal inhibitory interneurons (B5-I neurons), develop pathological itch. Here we characterize B5-I neurons and show that they belong to a neurochemically distinct subset. We provide cause-and-effect evidence that B5-I neurons inhibit itch and show that dynorphin, which is released from B5-I neurons, is a key neuromodulator of pruritus. Finally, we show that B5-I neurons are innervated by menthol-, capsaicin-, and mustard oil-responsive sensory neurons and are required for the inhibition of itch by menthol. These findings provide a cellular basis for the inhibition of itch by chemical counterstimuli and suggest that kappa opioids may be a broadly effective therapy for pathological itch. Spinal B5-I interneurons function to inhibit itch B5-I neurons release the kappa opioid dynorphin Kappa opioid signaling bidirectionally modulates itch within the spinal cord Spinal B5-I interneurons mediate the inhibition of itch by menthol
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Affiliation(s)
- Adam P Kardon
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA; University of Pittsburgh Pain Center, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA
| | - Erika Polgár
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Junichi Hachisuka
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA; University of Pittsburgh Pain Center, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA
| | - Lindsey M Snyder
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA; University of Pittsburgh Pain Center, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA
| | - Darren Cameron
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Sinead Savage
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Xiaoyun Cai
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA; University of Pittsburgh Pain Center, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA
| | - Sergei Karnup
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA; University of Pittsburgh Pain Center, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA
| | - Christopher R Fan
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA
| | - Gregory M Hemenway
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA
| | - Carcha S Bernard
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA
| | - Erica S Schwartz
- University of Pittsburgh Pain Center, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA; Department of Anesthesiology, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15213, USA
| | - Hiroshi Nagase
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Life Science Center of Tsukuba Advanced Research Alliance C-1F, 1-1-1 Tenoudai Tsukuba Ibaraki, Tsukuba 305-8577, Japan
| | - Christoph Schwarzer
- Department of Pharmacology, Innsbruck Medical University, A-6020 Innsbruck, Austria
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo 060-8638, Japan
| | - Takahiro Furuta
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Takeshi Kaneko
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - H Richard Koerber
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA; University of Pittsburgh Pain Center, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA
| | - Andrew J Todd
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
| | - Sarah E Ross
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA; University of Pittsburgh Pain Center, University of Pittsburgh, 200 Lothrop St. Pittsburgh, PA 15213, USA; Department of Anesthesiology, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15213, USA.
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Fu K, Qu L, Shimada SG, Nie H, LaMotte RH. Enhanced scratching elicited by a pruritogen and an algogen in a mouse model of contact hypersensitivity. Neurosci Lett 2014; 579:190-4. [PMID: 24704378 DOI: 10.1016/j.neulet.2014.03.062] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 03/24/2014] [Accepted: 03/26/2014] [Indexed: 02/08/2023]
Abstract
Chemical pruritogens and algogens evoke primarily itch and pain, respectively, when administered to the skin of healthy human subjects. However, the dominant sensory quality elicited by an algesic chemical stimulus may change in patients with chronic itch where bradykinin, elicits itch in addition to pain. Here we tested whether normally pruritic and algesic chemicals evoked abnormal itch- or pain-like behaviors in the mouse after the development of contact hypersensitivity (CHS), an animal model of allergic contact dermatitis. Mice previously sensitized to a hapten (squaric acid dibutylester) applied to the abdomen, exhibited spontaneous itch-like scratching and pain-like wiping directed to the site on the cheek of the CHS elicited by a subsequent challenge with the same hapten. In comparison with responses of control mice, CHS mice exhibited a significant increase in the scratching evoked by bovine adrenal medulla 8-22, a peptide that elicits a histamine-independent itch, but did not alter the scratching to histamine. Bradykinin, an algogen that elicited only wiping in control mice, additionally evoked significant scratching in CHS mice. Thus, within an area of CHS, histamine-independent itch is enhanced and chemically evoked pain is accompanied by itch.
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Affiliation(s)
- Kai Fu
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT 06520, USA; Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou 510632, Guangdong, China
| | - Lintao Qu
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Steven G Shimada
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Hong Nie
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of Pharmacy, Jinan University, Guangzhou 510632, Guangdong, China.
| | - Robert H LaMotte
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT 06520, USA.
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Qu L, Fan N, Ma C, Wang T, Han L, Fu K, Wang Y, Shimada SG, Dong X, LaMotte RH. Enhanced excitability of MRGPRA3- and MRGPRD-positive nociceptors in a model of inflammatory itch and pain. Brain 2014; 137:1039-50. [PMID: 24549959 PMCID: PMC3959553 DOI: 10.1093/brain/awu007] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 11/11/2013] [Accepted: 12/01/2013] [Indexed: 11/13/2022] Open
Abstract
Itch is a common symptom of diseases of the skin but can also accompany diseases of other tissues including the nervous system. Acute itch from chemicals experimentally applied to the skin is initiated and maintained by action potential activity in a subset of nociceptive neurons. But whether these pruriceptive neurons are active or might become intrinsically more excitable under the pathological conditions that produce persistent itch and nociceptive sensations in humans is largely unexplored. Recently, two distinct types of cutaneous nociceptive dorsal root ganglion neurons were identified as responding to pruritic chemicals and playing a role in itch sensation. One expressed the mas-related G-coupled protein receptor MRGPRA3 and the other MRGPRD (MRGPRA3+ and MRGPRD+ neurons, respectively). Here we tested whether these two distinct pruriceptive nociceptors exhibited an enhanced excitability after the development of contact hypersensitivity, an animal model of allergic contact dermatitis, a common pruritic disorder in humans. The characteristics of increased excitability of pruriceptive neurons during this disorder may also pertain to the same types of neurons active in other pruritic diseases or pathologies that affect the nervous system and other tissues or organs. We found that challenging the skin of the calf of the hind paw or the cheek of previously sensitized mice with the hapten, squaric acid dibutyl ester, produced symptoms of contact hypersensitivity including an increase in skin thickness and site-directed spontaneous pain-like (licking or wiping) and itch-like (biting or scratching) behaviours. Ablation of MRGPRA3+ neurons led to a significant reduction in spontaneous scratching of the hapten-challenged nape of the neck of previously sensitized mice. In vivo, electrophysiological recordings revealed that MRGPRA3+ and MRGPRD+ neurons innervating the hapten-challenged skin exhibited a greater incidence of spontaneous activity and/or abnormal after-discharges in response to mechanical and heat stimuli applied to their receptive fields compared with neurons from the vehicle-treated control animals. Whole-cell recordings in vitro showed that both MRGPRA3+ and MRGPRD+ neurons from hapten-challenged mice displayed a significantly more depolarized resting membrane potential, decreased rheobase, and greater number of action potentials at twice rheobase compared with neurons from vehicle controls. These signs of neuronal hyperexcitability were associated with a significant increase in the peak amplitude of tetrodotoxin-sensitive and resistant sodium currents. Thus, the hyperexcitability of MRGPRA3+ and MRGPRD+ neurons, brought about in part by enhanced sodium currents, may contribute to the spontaneous itch- and pain-related behaviours accompanying contact hypersensitivity and/or other inflammatory diseases in humans.
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Affiliation(s)
- Lintao Qu
- 1 Department of Anaesthesiology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Ni Fan
- 1 Department of Anaesthesiology, Yale University School of Medicine, New Haven, CT, 06520, USA
- 2 Guangzhou Brain Hospital, the Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China 510370
| | - Chao Ma
- 1 Department of Anaesthesiology, Yale University School of Medicine, New Haven, CT, 06520, USA
- 3 Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Department of Anatomy, Histology and Embryology, Beijing, China
| | - Tao Wang
- 1 Department of Anaesthesiology, Yale University School of Medicine, New Haven, CT, 06520, USA
- 3 Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Department of Anatomy, Histology and Embryology, Beijing, China
| | - Liang Han
- 4 Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Kai Fu
- 1 Department of Anaesthesiology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Yingdi Wang
- 5 Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Steven G. Shimada
- 1 Department of Anaesthesiology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Xinzhong Dong
- 4 Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Robert H. LaMotte
- 1 Department of Anaesthesiology, Yale University School of Medicine, New Haven, CT, 06520, USA
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Liu X, Zhang J, Zhao H, Mei H, Lian Q, Shangguan W. The effect of propofol on intrathecal morphine-induced pruritus and its mechanism. Anesth Analg 2014; 118:303-309. [PMID: 24445631 DOI: 10.1213/ane.0000000000000086] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Previous studies have shown that a low dose of propofol IV bolus had a beneficial effect on intrathecal morphine-induced pruritus in humans. However, its exact mechanism has not been fully understood. In this study, we hypothesized that propofol relieved intrathecal morphine-induced pruritus in rats by upregulating the expression of cannabinoid-1 (CB[1]) receptors in anterior cingulate cortex (ACC). METHODS Twenty-four Sprague-Dawley rats were divided into a control group and 20, 40, 80 μg/kg morphine groups to create an intrathecal morphine-induced scratching model. The effects of propofol on intrathecal 40 μg/kg morphine-induced scratching responses were then evaluated. Sixty rats were randomly assigned to control, normal saline, intralipid, and propofol groups, with pruritus behavior observation or killed 8 minutes after venous injection of normal saline, intralipid, or propofol, and brain tissues were then collected for assay. Immunohistochemistry was then performed to identify the expression of CB (1) receptor in ACC, and the concentration of CB(1) receptor in ACC was determined by Western blot analysis. RESULTS Compared with the control group, rats in the 20, 40, 80 μg/kg morphine groups had higher mean scratching response rates after intrathecal morphine injection (P =0.020, 0.005, and 0.002, respectively). There was a statistical difference between 20 and 40 μg/kg morphine groups at 10 to 15 and 15 to 20 timepoints after intrathecal morphine injection (P = 0.049 and 0.017, respectively). Propofol almost abolished the scratching response that was induced by 40 μg/kg intrathecal morphine injection (F[2, 15] = 46.87, P < 0.001; F[22, 165] = 2.37, P = 0.001). Compared with the intralipid and normal saline groups, the scratching behavior was significantly attenuated in the propofol group (P < 0.001). Compared with control, normal saline, and intralipid groups, the protein expression of CB(1) receptor in ACC (Western blot) in the propofol group increased (0.86 ± 0.21, 0.94 ± 0.18, 0.86 ± 0.13, and 1.34 ± 0.32, respectively, P < 0.001). There was no significant difference among control, normal saline, and intralipid groups. Compared with the control, normal saline, and intralipid groups, the average number of neurons of CB(1) receptor in the ACC area were higher in the propofol group (21.0 ± 1.4, 19.3 ± 1.8, 24.8 ± 7.7, and 37.2 ± 3.3, respectively, P < 0.001). CONCLUSIONS Morphine elicits dose-independent scratching responses after intrathecal injection in rats. Morphine 40 μg/kg intrathecal injection-induced scratching responses can be prevented by propofol. Increased protein expression of CB(1) receptors in ACC may contribute to the reversal of intrathecal morphine-induced scratching.
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Affiliation(s)
- Xiulan Liu
- From the Department of Anesthesiology, the 2nd Affiliated Hospital of WenZhou Medical College, Wenzhou, China
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Abstract
Chemicals that are used experimentally to evoke itch elicit activity in diverse subpopulations of cutaneous pruriceptive neurons, all of which also respond to painful stimuli. However, itch is distinct from pain: it evokes different behaviours, such as scratching, and originates from the skin or certain mucosae but not from muscle, joints or viscera. New insights regarding the neurons that mediate the sensation of itch have been gained from experiments in which gene expression has been manipulated in different types of pruriceptive neurons as well as from comparisons between psychophysical measurements of itch and the neuronal discharges and other properties of peripheral and central pruriceptive neurons.
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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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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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Abstract
INTRODUCTION Chronic pruritus (CP), defined as itch lasting for > 6 weeks, is a burdensome symptom of several different diseases, dermatological and systemic, with a high negative impact on the quality of life of patients. Given the manifold aetiologies of CP, therapy is often difficult. In recent years, however, novel substances have been developed for treatment of certain CP entities and identified targets. AREAS COVERED In this review, the authors present a survey of targets currently believed to be promising (H4R, IL-31, MOR, KOR, GRPR, NGF, NK-1R, TRP channels) and related investigational drugs that are in the preclinical or clinical stage of development. Some substances have already undergone clinical testing, but only one of them (nalfurafine) has been licensed so far. Many of them are most likely to exert their effects on the skin and interfere there with the cutaneous neurobiology of CP. EXPERT OPINION Currently, the most promising candidates for new therapeutic agents in CP are neurokinin-1 receptor antagonists and substances targeting the kappa- or mu-opioid receptor, or both. They have the potential to target the neuronal pathway of CP and are thus of interest for several CP entities. The goal for the coming years is to validate these concepts and move forward in developing new drugs for the therapy of CP.
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Affiliation(s)
- Heike Benecke
- University Medicine Göttingen, Center Nanoscale Microscopy and Molecular Physiology of the Brain, Humboldtallee 23, 37073 Göttingen, Germany
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Olivry T, Bizikova P, Paps JS, Dunston S, Lerner EA, Yosipovitch G. Cowhage can induce itch in the atopic dog. Exp Dermatol 2013; 22:435-7. [PMID: 23711071 PMCID: PMC3758897 DOI: 10.1111/exd.12158] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2013] [Indexed: 11/29/2022]
Abstract
Itch is a cardinal symptom of atopic dermatitis in humans and dogs. Until now, experimental induction of itch in dogs has proven difficult. The objectives of this study were to determine whether protease-rich spicules, protein extracts and the protease mucunain of the tropical legume cowhage provoked itch and inflammation when rubbed onto canine skin. Native spicules variably induced itch manifestations in about half of the dogs, while challenges with protease-deactivated spicules remained negative. The epicutaneous application of cowhage extract and mucunain after microneedle roller usage also induced pruritus and inflammation. Importantly, there was an interindividual inconsistency in pruritus and inflammation induction and also marked differences in pruritus intensity after challenge. In conclusion, cowhage spicules, protein-rich extracts and mucunain can all induce pruritus and inflammation in dogs as in other species, but the inconsistency of provocation is currently a limitation of this challenge type for future studies of pruritus in dogs.
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Affiliation(s)
- Thierry Olivry
- Department of Clinical Sciences, College of Veterinary Medicine, NC State University, Raleigh, NC, USA
- Center for Comparative Medicine and Translational Research, NC State University, Raleigh, NC, USA
| | - Petra Bizikova
- Department of Clinical Sciences, College of Veterinary Medicine, NC State University, Raleigh, NC, USA
- Center for Comparative Medicine and Translational Research, NC State University, Raleigh, NC, USA
| | - Judy S. Paps
- Department of Clinical Sciences, College of Veterinary Medicine, NC State University, Raleigh, NC, USA
| | - Stan Dunston
- Department of Clinical Sciences, College of Veterinary Medicine, NC State University, Raleigh, NC, USA
| | - Ethan A. Lerner
- Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, MA, USA
| | - Gil Yosipovitch
- Department of Dermatology, Wake Forest University Medical Center, Medical Center Boulevard, Winston-Salem, NC, USA
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Activity-dependent silencing reveals functionally distinct itch-generating sensory neurons. Nat Neurosci 2013; 16:910-8. [PMID: 23685721 PMCID: PMC3695070 DOI: 10.1038/nn.3404] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 04/18/2013] [Indexed: 02/06/2023]
Abstract
The peripheral terminals of primary sensory neurons detect histamine and non-histamine itch-provoking ligands through molecularly distinct transduction mechanisms. It remains unclear, however, whether these distinct pruritogens activate the same or different afferent fibers. We utilized a strategy of reversibly silencing specific subsets of murine pruritogen-sensitive sensory axons by targeted delivery of a charged sodium-channel blocker and found that functional blockade of histamine itch did not affect the itch evoked by chloroquine or SLIGRL-NH2, and vice versa. Notably, blocking itch-generating fibers did not reduce pain-associated behavior. However, silencing TRPV1+ or TRPA1+ neurons allowed AITC or capsaicin respectively to evoke itch, implying that certain peripheral afferents may normally indirectly inhibit algogens from eliciting itch. These findings support the presence of functionally distinct sets of itch-generating neurons and suggest that targeted silencing of activated sensory fibers may represent a clinically useful anti-pruritic therapeutic approach for histaminergic and non-histaminergic pruritus.
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Gomes LO, Hara DB, Rae GA. Endothelin-1 induces itch and pain in the mouse cheek model. Life Sci 2012; 91:628-33. [DOI: 10.1016/j.lfs.2012.03.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 03/05/2012] [Accepted: 03/08/2012] [Indexed: 11/29/2022]
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Spradley JM, Davoodi A, Carstens MI, Carstens E. Effects of acute stressors on itch- and pain-related behaviors in rats. Pain 2012; 153:1890-1897. [PMID: 22770638 DOI: 10.1016/j.pain.2012.05.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 05/26/2012] [Accepted: 05/29/2012] [Indexed: 11/18/2022]
Abstract
Many acute stressors reduce pain, a phenomenon called stress-induced antinociception (SIA). Stress also is associated with increased scratching in chronic itch conditions. We investigated effects of acute stressors on facial itch and pain using a recently introduced rat model. Under baseline (no-swim) conditions, intradermal (id) cheek microinjection of the pruritogen serotonin (5-HT) selectively elicited hindlimb scratch bouts, whereas the algogen mustard oil (allyl isothiocyanate [AITC]) selectively elicited ipsilateral forepaw swipes, directed to the cheek injection site. To test effects of swim stress, rats received id cheek microinjection of 5-HT (1%), AITC (10%), or vehicle, and were then subjected to one of the following swim conditions: (1) weak SIA (W-SIA), (2) naltrexone-sensitive SIA (intermediate or I-SIA), or (3) naltrexone-insensitive SIA (strong or S-SIA). After the swim, we recorded the number of hindlimb scratch bouts and forelimb swipes directed to the cheek injection site, as well as facial grooming by both forepaws. Under S-SIA, AITC-evoked swiping and 5-HT-evoked scratching were both reduced. I-SIA reduced AITC-evoked swiping with no effect on 5-HT-evoked scratching. Facial grooming immediately post-swim was suppressed by S-SIA, but not I- or W-SIA. W-SIA tended to equalize scratching and swiping elicited by 5-HT and AITC compared with no-swim controls, suggesting altered itch and pain processing. Exercise (wheel-running), novelty, cold exposure, and fear (shaker table), key components of swim stress, differentially affected tail-flick latencies and 5-HT-evoked swiping and scratching behavior. Thus, itch and pain can be simultaneously suppressed by a combination of acute stress-related factors via an opioid-independent mechanism.
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Affiliation(s)
- Jessica Marie Spradley
- Department of Neurobiology, Physiology and Behavior, University of California-Davis, Davis, CA, USA
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Andoh T, Takayama Y, Yamakoshi T, Lee JB, Sano A, Shimizu T, Kuraishi Y. Involvement of serine protease and proteinase-activated receptor 2 in dermatophyte-associated itch in mice. J Pharmacol Exp Ther 2012; 343:91-6. [PMID: 22761302 DOI: 10.1124/jpet.112.195222] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We investigated the involvement of serine protease and proteinase-activated receptor 2 (PAR(2)) in dermatophyte-induced itch in mice. An intradermal injection of an extract of the dermatophyte Arthroderma vanbreuseghemii (ADV) induced hind-paw scratching, an itch-related behavior. ADV extract-induced scratching was inhibited by the opioid receptor antagonists naloxone and naltrexone, the serine protease inhibitor nafamostat mesylate, and the PAR(2) receptor antagonist FSLLRY-NH(2). ADV extract-induced scratching was not inhibited by the H(1) histamine receptor antagonist terfenadine or by mast cell deficiency. Heat pretreatment of the ADV extract markedly reduced the scratch-inducing and serine protease activities. Proteolytic cleavage within the extracellular N terminus of the PAR(2) receptor exposes a sequence that serves as a tethered ligand for the receptor. The ADV extract as well as tryptase and trypsin cleaved a synthetic N-terminal peptide of the PAR(2) receptor. The present results suggest that serine protease secreted by dermatophytes causes itching through activation of the PAR(2) receptors, which may be a causal mechanism of dernatophytosis itch.
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Affiliation(s)
- Tsugunobu Andoh
- Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
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