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Shen Q, Tang X, Wen X, Cheng S, Xiao P, Zang SK, Shen DD, Jiang L, Zheng Y, Zhang H, Xu H, Mao C, Zhang M, Hu W, Sun JP, Zhang Y, Chen Z. Molecular Determinant Underlying Selective Coupling of Primary G-Protein by Class A GPCRs. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2310120. [PMID: 38647423 DOI: 10.1002/advs.202310120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/02/2024] [Indexed: 04/25/2024]
Abstract
G-protein-coupled receptors (GPCRs) transmit downstream signals predominantly via G-protein pathways. However, the conformational basis of selective coupling of primary G-protein remains elusive. Histamine receptors H2R and H3R couple with Gs- or Gi-proteins respectively. Here, three cryo-EM structures of H2R-Gs and H3R-Gi complexes are presented at a global resolution of 2.6-2.7 Å. These structures reveal the unique binding pose for endogenous histamine in H3R, wherein the amino group interacts with E2065.46 of H3R instead of the conserved D1143.32 of other aminergic receptors. Furthermore, comparative analysis of the H2R-Gs and H3R-Gi complexes reveals that the structural geometry of TM5/TM6 determines the primary G-protein selectivity in histamine receptors. Machine learning (ML)-based structuromic profiling and functional analysis of class A GPCR-G-protein complexes illustrate that TM5 length, TM5 tilt, and TM6 outward movement are key determinants of the Gs and Gi/o selectivity among the whole Class A family. Collectively, the findings uncover the common structural geometry within class A GPCRs that determines the primary Gs- and Gi/o-coupling selectivity.
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Affiliation(s)
- Qingya Shen
- Department of Pharmacology and Department of Pathology of Sir Run Run Shaw Hospital & Liangzhu Laboratory, Hangzhou, 310058, China
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Xinyan Tang
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Xin Wen
- Advanced Medical Research Institute, Meili Lake Translational Research Park, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China
- Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, 250012, China
| | - Shizhuo Cheng
- Department of Pharmacology and Department of Pathology of Sir Run Run Shaw Hospital & Liangzhu Laboratory, Hangzhou, 310058, China
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Medicine, Hangzhou, 310058, China
- College of Computer Science and Technology, Zhejiang University, Hangzhou, 310027, China
| | - Peng Xiao
- Advanced Medical Research Institute, Meili Lake Translational Research Park, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China
- Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, 250012, China
| | - Shao-Kun Zang
- Department of Pharmacology and Department of Pathology of Sir Run Run Shaw Hospital & Liangzhu Laboratory, Hangzhou, 310058, China
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Dan-Dan Shen
- Department of Pharmacology and Department of Pathology of Sir Run Run Shaw Hospital & Liangzhu Laboratory, Hangzhou, 310058, China
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Lei Jiang
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Yanrong Zheng
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, 310053, China
| | - Huibing Zhang
- Department of Pharmacology and Department of Pathology of Sir Run Run Shaw Hospital & Liangzhu Laboratory, Hangzhou, 310058, China
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Haomang Xu
- Department of Pharmacology and Department of Pathology of Sir Run Run Shaw Hospital & Liangzhu Laboratory, Hangzhou, 310058, China
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Chunyou Mao
- Department of Pharmacology and Department of Pathology of Sir Run Run Shaw Hospital & Liangzhu Laboratory, Hangzhou, 310058, China
- Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310016, China
- Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Zhejiang University, Hangzhou, 310016, China
| | - Min Zhang
- College of Computer Science and Technology, Zhejiang University, Hangzhou, 310027, China
| | - Weiwei Hu
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jin-Peng Sun
- Advanced Medical Research Institute, Meili Lake Translational Research Park, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China
- Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, 250012, China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, 100191, China
| | - Yan Zhang
- Department of Pharmacology and Department of Pathology of Sir Run Run Shaw Hospital & Liangzhu Laboratory, Hangzhou, 310058, China
- MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Zhong Chen
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, 310058, China
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, 310053, China
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Chu C, Liu S, Nie L, Hu H, Liu Y, Yang J. The interactions and biological pathways among metabolomics products of patients with coronary heart disease. Biomed Pharmacother 2024; 173:116305. [PMID: 38422653 DOI: 10.1016/j.biopha.2024.116305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 02/06/2024] [Accepted: 02/17/2024] [Indexed: 03/02/2024] Open
Abstract
BACKGROUND Through bioinformatics analysis, this study explores the interactions and biological pathways involving metabolomic products in patients diagnosed with coronary heart disease (CHD). METHODS A comprehensive search for relevant studies focusing on metabolomics analysis in CHD patients was conducted across databases including CNKI, Wanfang, VIP, CBM, PubMed, Cochrane Library, Nature, Web of Science, Springer, and Science Direct. Metabolites reported in the literature underwent statistical analysis and summarization, with the identification of differential metabolites. The pathways associated with these metabolites were examined using the Kyoto Encyclopedia of Genes and Genomes (KEGG). Molecular annotation of metabolites and their relationships with enzymes or transporters were elucidated through analysis with the Human Metabolome Database (HMDB). Visual representation of the properties related to these metabolites was achieved using Metabolomics Pathway Analysis (metPA). RESULTS A total of 13 literatures satisfying the criteria for enrollment were included. A total of 91 metabolites related to CHD were preliminarily screened, and 87 effective metabolites were obtained after the unrecognized metabolites were excluded. A total of 45 pathways were involved. Through the topology analysis (TPA) of pathways, their influence values were calculated, and 13 major metabolic pathways were selected. The pathways such as Phenylalanine, tyrosine, and tryptophan biosynthesis, Citrate cycle (TCA cycle), Glyoxylate and dicarboxylate metabolism, and Glycine, serine, and threonine metabolism primarily involved the regulation of processes and metabolites related to inflammation, oxidative stress, one-carbon metabolism, energy metabolism, lipid metabolism, immune regulation, and nitric oxide expression. CONCLUSION Multiple pathways, including Phenylalanine, tyrosine, and tryptophan biosynthesis, Citrate cycle (TCA cycle), Glyoxylate and dicarboxylate metabolism, and Glycine, serine, and threonine metabolism, were involved in the occurrence of CHD. The occurrence of CHD is primarily associated with the regulation of processes and metabolites related to inflammation, oxidative stress, one-carbon metabolism, energy metabolism, lipid metabolism, immune regulation, and nitric oxide expression.
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Affiliation(s)
- Chun Chu
- Department of Pharmacy, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan Province 421001, China
| | - Shengquan Liu
- Department of Cardiology, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan Province 421001, China
| | - Liangui Nie
- Department of Cardiology, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan Province 421001, China
| | - Hongming Hu
- Department of Cardiology, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan Province 421001, China
| | - Yi Liu
- Department of Pharmacy, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan Province 421001, China.
| | - Jun Yang
- Department of Cardiology, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan Province 421001, China.
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Kong L, Domarecka E, Szczepek AJ. Histamine and Its Receptors in the Mammalian Inner Ear: A Scoping Review. Brain Sci 2023; 13:1101. [PMID: 37509031 PMCID: PMC10376984 DOI: 10.3390/brainsci13071101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/14/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023] Open
Abstract
BACKGROUND Histamine is a widely distributed biogenic amine with multiple biological functions mediated by specific receptors that determine the local effects of histamine. This review aims to summarize the published findings on the expression and functional roles of histamine receptors in the inner ear and to identify potential research hotspots and gaps. METHODS A search of the electronic databases PubMed, Web of Science, and OVID EMBASE was performed using the keywords histamine, cochlea*, and inner ear. Of the 181 studies identified, 18 eligible publications were included in the full-text analysis. RESULTS All four types of histamine receptors were identified in the mammalian inner ear. The functional studies of histamine in the inner ear were mainly in vitro. Clinical evidence suggests that histamine and its receptors may play a role in Ménière's disease, but the exact mechanism is not fully understood. The effects of histamine on hearing development remain unclear. CONCLUSIONS Existing studies have successfully determined the expression of all four histamine receptors in the mammalian inner ear. However, further functional studies are needed to explore the potential of histamine receptors as targets for the treatment of hearing and balance disorders.
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Affiliation(s)
- Lingyi Kong
- Department of Otorhinolaryngology, Head and Neck Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Ewa Domarecka
- Department of Otorhinolaryngology, Head and Neck Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Agnieszka J Szczepek
- Department of Otorhinolaryngology, Head and Neck Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany
- Faculty of Medicine and Health Sciences, University of Zielona Gora, 65-046 Zielona Gora, Poland
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Sanz-Vicente I, Rivero I, Marcuello L, Montano MP, de Marcos S, Galbán J. Portable colorimetric enzymatic disposable biosensor for histamine and simultaneous histamine/tyramine determination using a smartphone. Anal Bioanal Chem 2023; 415:1777-1786. [PMID: 36790459 PMCID: PMC9992026 DOI: 10.1007/s00216-023-04583-0] [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: 10/18/2022] [Revised: 01/27/2023] [Accepted: 02/01/2023] [Indexed: 02/16/2023]
Abstract
Tyramine oxidase (TAO), peroxidase (HRP), and Amplex Red (AR) have been immobilized on cellulose to obtain disposable biosensors for the determination of histamine. During the enzymatic reaction, AR is oxidized and a pink spot is obtained. Using a smartphone and measuring the G (green) color coordinate, histamine can be determined in the presence of other biogenic amines (putrescine and cadaverine) in concentrations ranging from 2·10-5 M to 5·10-4 M with a 7.5·10-6 M limit of detection (LoD). Despite tyramine interference, experimental conditions are provided which allow rapid and simple histamine and simultaneous histamine/tyramine (semi)quantitative determination in mixtures. Finally, tyramine and histamine were determined in a tuna extract with good results (compared to the reference HPLC-MS method). The methodology can also be applied in solution allowing histamine (and simultaneous histamine/tyramine) determination with a lower LoD (1.8·10-7 M) and a similar selectivity.
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Affiliation(s)
- Isabel Sanz-Vicente
- Nanosensors and Bioanalytical Systems (N&SB), Analytical Chemistry Department, Faculty of Sciences, Aragon Institute of Nanoscience, University of Zaragoza, 50009, Saragossa, Spain.
| | - Irina Rivero
- Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, 50009, Saragossa, Spain
| | - Lucía Marcuello
- Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, 50009, Saragossa, Spain
| | - María Pilar Montano
- Analytical Chemistry Department, Faculty of Sciences, University of Zaragoza, 50009, Saragossa, Spain
| | - Susana de Marcos
- Nanosensors and Bioanalytical Systems (N&SB), Analytical Chemistry Department, Faculty of Sciences, Aragon Institute of Nanoscience, University of Zaragoza, 50009, Saragossa, Spain
| | - Javier Galbán
- Nanosensors and Bioanalytical Systems (N&SB), Analytical Chemistry Department, Faculty of Sciences, Aragon Institute of Nanoscience, University of Zaragoza, 50009, Saragossa, Spain
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Mast Cell Activation Syndrome in COVID-19 and Female Reproductive Function: Theoretical Background vs. Accumulating Clinical Evidence. J Immunol Res 2022; 2022:9534163. [PMID: 35785029 PMCID: PMC9242765 DOI: 10.1155/2022/9534163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 05/19/2022] [Accepted: 06/01/2022] [Indexed: 12/14/2022] Open
Abstract
Coronavirus disease 2019 (COVID-19), a pandemic disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, can affect almost all systems and organs of the human body, including those responsible for reproductive function in women. The multisystem inflammatory response in COVID-19 shows many analogies with mast cell activation syndrome (MCAS), and MCAS may be an important component in the course of COVID-19. Of note, the female sex hormones estradiol (E2) and progesterone (P4) significantly influence mast cell (MC) behavior. This review presents the importance of MCs and the mediators from their granules in the female reproductive system, including pregnancy, and discusses the mechanism of potential disorders related to MCAS. Then, the available data on COVID-19 in the context of hormonal disorders, the course of endometriosis, female fertility, and the course of pregnancy were compiled to verify intuitively predicted threats. Surprisingly, although COVID-19 hyperinflammation and post-COVID-19 illness may be rooted in MCAS, the available clinical data do not provide grounds for treating this mechanism as significantly increasing the risk of abnormal female reproductive function, including pregnancy. Further studies in the context of post COVID-19 condition (long COVID), where inflammation and a procoagulative state resemble many aspects of MCAS, are needed.
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Neumann J, Kirchhefer U, Dhein S, Hofmann B, Gergs U. The Roles of Cardiovascular H 2-Histamine Receptors Under Normal and Pathophysiological Conditions. Front Pharmacol 2022; 12:732842. [PMID: 34987383 PMCID: PMC8720924 DOI: 10.3389/fphar.2021.732842] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 11/02/2021] [Indexed: 12/11/2022] Open
Abstract
This review addresses pharmacological, structural and functional relationships among H2-histamine receptors and H1-histamine receptors in the mammalian heart. The role of both receptors in the regulation of force and rhythm, including their electrophysiological effects on the mammalian heart, will then be discussed in context. The potential clinical role of cardiac H2-histamine-receptors in cardiac diseases will be examined. The use of H2-histamine receptor agonists to acutely increase the force of contraction will be discussed. Special attention will be paid to the potential role of cardiac H2-histamine receptors in the genesis of cardiac arrhythmias. Moreover, novel findings on the putative role of H2-histamine receptor antagonists in treating chronic heart failure in animal models and patients will be reviewed. Some limitations in our biochemical understanding of the cardiac role of H2-histamine receptors will be discussed. Recommendations for further basic and translational research on cardiac H2-histamine receptors will be offered. We will speculate whether new knowledge might lead to novel roles of H2-histamine receptors in cardiac disease and whether cardiomyocyte specific H2-histamine receptor agonists and antagonists should be developed.
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Affiliation(s)
- Joachim Neumann
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Uwe Kirchhefer
- Institut für Pharmakologie und Toxikologie, Westfälische Wilhelms-Universität, Münster, Germany
| | - Stefan Dhein
- Landratsamt Altenburger Land, Altenburg, Germany
| | - Britt Hofmann
- Herzchirurgie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Ulrich Gergs
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
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Drosophila SLC22 Orthologs Related to OATs, OCTs, and OCTNs Regulate Development and Responsiveness to Oxidative Stress. Int J Mol Sci 2020; 21:ijms21062002. [PMID: 32183456 PMCID: PMC7139749 DOI: 10.3390/ijms21062002] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/11/2020] [Accepted: 03/13/2020] [Indexed: 12/14/2022] Open
Abstract
The SLC22 family of transporters is widely expressed, evolutionarily conserved, and plays a major role in regulating homeostasis by transporting small organic molecules such as metabolites, signaling molecules, and antioxidants. Analysis of transporters in fruit flies provides a simple yet orthologous platform to study the endogenous function of drug transporters in vivo. Evolutionary analysis of Drosophila melanogaster putative SLC22 orthologs reveals that, while many of the 25 SLC22 fruit fly orthologs do not fall within previously established SLC22 subclades, at least four members appear orthologous to mammalian SLC22 members (SLC22A16:CG6356, SLC22A15:CG7458, CG7442 and SLC22A18:CG3168). We functionally evaluated the role of SLC22 transporters in Drosophila melanogaster by knocking down 14 of these genes. Three putative SLC22 ortholog knockdowns-CG3168, CG6356, and CG7442/SLC22A-did not undergo eclosion and were lethal at the pupa stage, indicating the developmental importance of these genes. Additionally, knocking down four SLC22 members increased resistance to oxidative stress via paraquat testing (CG4630: p < 0.05, CG6006: p < 0.05, CG6126: p < 0.01 and CG16727: p < 0.05). Consistent with recent evidence that SLC22 is central to a Remote Sensing and Signaling Network (RSSN) involved in signaling and metabolism, these phenotypes support a key role for SLC22 in handling reactive oxygen species.
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MacDonald EA, Rose RA, Quinn TA. Neurohumoral Control of Sinoatrial Node Activity and Heart Rate: Insight From Experimental Models and Findings From Humans. Front Physiol 2020; 11:170. [PMID: 32194439 PMCID: PMC7063087 DOI: 10.3389/fphys.2020.00170] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 02/13/2020] [Indexed: 12/22/2022] Open
Abstract
The sinoatrial node is perhaps one of the most important tissues in the entire body: it is the natural pacemaker of the heart, making it responsible for initiating each-and-every normal heartbeat. As such, its activity is heavily controlled, allowing heart rate to rapidly adapt to changes in physiological demand. Control of sinoatrial node activity, however, is complex, occurring through the autonomic nervous system and various circulating and locally released factors. In this review we discuss the coupled-clock pacemaker system and how its manipulation by neurohumoral signaling alters heart rate, considering the multitude of canonical and non-canonical agents that are known to modulate sinoatrial node activity. For each, we discuss the principal receptors involved and known intracellular signaling and protein targets, highlighting gaps in our knowledge and understanding from experimental models and human studies that represent areas for future research.
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Affiliation(s)
- Eilidh A MacDonald
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
| | - Robert A Rose
- Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada.,School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
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Drummond PD, Lester B. Loratadine augments emotional blushing. Eur Neuropsychopharmacol 2018; 28:1284-1288. [PMID: 30153954 DOI: 10.1016/j.euroneuro.2018.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/30/2018] [Accepted: 08/07/2018] [Indexed: 11/25/2022]
Abstract
The aim of this study was to determine whether loratadine, a selective inverse agonist of peripheral histamine H1 receptors, would reduce emotional blushing. Loratadine (10 mg) or placebo was administered orally one hour before 31 healthy participants sang a children's nursery rhyme to evoke embarrassment and blushing. Skin blood flow was monitored via a laser Doppler probe attached to the cheek. Increases in facial blood flow while participants sang were greater in the loratadine than the placebo group (mean increase ± standard deviation 71 ± 52% in the loratadine group versus 35 ± 37%, p = .036). However, perceptions of blushing were similar in both groups. These findings suggest that loratadine augmented blushing rather than inhibiting it. Thus, histamine released during blushing may inhibit acute increases in facial blood flow by evoking H1 receptor-mediated vasoconstriction.
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Affiliation(s)
- Peter D Drummond
- School of Psychology and Exercise Science, Murdoch University, Perth, Western Australia, Australia.
| | - Bronwyn Lester
- School of Psychology and Exercise Science, Murdoch University, Perth, Western Australia, Australia
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