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Tiligada E, Stefanaki C, Ennis M, Neumann D. Opportunities and challenges in the therapeutic exploitation of histamine and histamine receptor pharmacology in inflammation-driven disorders. Pharmacol Ther 2024; 263:108722. [PMID: 39306197 DOI: 10.1016/j.pharmthera.2024.108722] [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: 05/24/2024] [Revised: 07/31/2024] [Accepted: 09/13/2024] [Indexed: 09/26/2024]
Abstract
Inflammation-driven diseases encompass a wide array of pathological conditions characterised by immune system dysregulation leading to tissue damage and dysfunction. Among the myriad of mediators involved in the regulation of inflammation, histamine has emerged as a key modulatory player. Histamine elicits its actions through four rhodopsin-like G-protein-coupled receptors (GPCRs), named chronologically in order of discovery as histamine H1, H2, H3 and H4 receptors (H1-4R). The relatively low affinity H1R and H2R play pivotal roles in mediating allergic inflammation and gastric acid secretion, respectively, whereas the high affinity H3R and H4R are primarily linked to neurotransmission and immunomodulation, respectively. Importantly, however, besides the H4R, both H1R and H2R are also crucial in driving immune responses, the H2R tending to promote yet ill-defined and unexploited suppressive, protective and/or resolving processes. The modulatory action of histamine via its receptors on inflammatory cells is described in detail. The potential therapeutic value of the most recently discovered H4R in inflammatory disorders is illustrated via a selection of preclinical models. The clinical trials with antagonists of this receptor are discussed and possible reasons for their lack of success described.
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Affiliation(s)
- Ekaterini Tiligada
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
| | - Charikleia Stefanaki
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece; University Research Institute of Maternal and Child Health and Precision Medicine, "Aghia Sophia" Children's Hospital, Athens, Greece
| | - Madeleine Ennis
- The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queens University Belfast, Belfast, UK
| | - Detlef Neumann
- Institute of Pharmacology, Hannover Medical School, Hannover, Germany
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Basophil activation test in interstitial nephritis. Some comments. Nefrologia 2019; 40:480-481. [PMID: 31627972 DOI: 10.1016/j.nefro.2019.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 06/11/2019] [Indexed: 11/21/2022] Open
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Varricchi G, Raap U, Rivellese F, Marone G, Gibbs BF. Human mast cells and basophils-How are they similar how are they different? Immunol Rev 2019; 282:8-34. [PMID: 29431214 DOI: 10.1111/imr.12627] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mast cells and basophils are key contributors to allergies and other inflammatory diseases since they are the most prominent source of histamine as well as numerous additional inflammatory mediators which drive inflammatory responses. However, a closer understanding of their precise roles in allergies and other pathological conditions has been marred by the considerable heterogeneity that these cells display, not only between mast cells and basophils themselves but also across different tissue locations and species. While both cell types share the ability to rapidly degranulate and release histamine following high-affinity IgE receptor cross-linking, they differ markedly in their ability to either react to other stimuli, generate inflammatory eicosanoids or release immunomodulating cytokines and chemokines. Furthermore, these cells display considerable pharmacological heterogeneity which has stifled attempts to develop more effective anti-allergic therapies. Mast cell- and basophil-specific transcriptional profiling, at rest and after activation by innate and adaptive stimuli, may help to unravel the degree to which these cells differ and facilitate a clearer understanding of their biological functions and how these could be targeted by new therapies.
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Affiliation(s)
- Gilda Varricchi
- Department of Translational Medical Sciences and Center for Basic and Clinical Immunology Research, University of Naples Federico II, Naples, Italy.,WAO Center of Excellence, Naples, Italy
| | - Ulrike Raap
- Department of Dermatology and Allergology, University of Oldenburg, Oldenburg, Germany
| | - Felice Rivellese
- Department of Translational Medical Sciences and Center for Basic and Clinical Immunology Research, University of Naples Federico II, Naples, Italy.,WAO Center of Excellence, Naples, Italy.,Centre for Experimental Medicine and Rheumatology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Gianni Marone
- Department of Translational Medical Sciences and Center for Basic and Clinical Immunology Research, University of Naples Federico II, Naples, Italy.,WAO Center of Excellence, Naples, Italy.,Institute of Experimental Endocrinology and Oncology "Gaetano Salvatore" (IEOS), National Research Council (CNR), Naples, Italy
| | - Bernhard F Gibbs
- Department of Dermatology and Allergology, University of Oldenburg, Oldenburg, Germany
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Molecular targets on mast cells and basophils for novel therapies. J Allergy Clin Immunol 2014; 134:530-44. [DOI: 10.1016/j.jaci.2014.03.007] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/24/2014] [Accepted: 03/07/2014] [Indexed: 01/14/2023]
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Satti MZ, Cahen P, Skov PS, Joseph S, Jones FM, Fitzsimmons C, Hoffmann KF, Reimert C, Curtis Kariuki H, Kazibwe F, Mwatha JK, Kimani G, Vennervald BJ, Ouma JH, Kabatereine NB, Dunne DW. Changes in IgE- and antigen-dependent histamine-release in peripheral blood of Schistosoma mansoni-infected Ugandan fishermen after treatment with praziquantel. BMC Immunol 2004; 5:6. [PMID: 15102330 PMCID: PMC419341 DOI: 10.1186/1471-2172-5-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2004] [Accepted: 04/21/2004] [Indexed: 11/16/2022] Open
Abstract
Background Parasite-specific IgE levels correlate with human resistance to reinfection with Schistosoma spp. after chemotherapy. Although the role of eosinophils in schistosomiasis has been the focus of a great deal of important research, the involvement of other Fcε receptor-bearing cells, such as mast cells and basophils, has not been investigated in relation to human immunity to schistosomes. Chemotherapy with praziquantel (PZQ) kills schistosomes living in an in vivo blood environment rich in IgE, eosinophils and basophils. This releases parasite Ags that have the potential to cross-link cell-bound IgE. However, systemic hypersensitivity reactions are not induced by treatment. Here, we describe the effects of schistosomiasis, and its treatment, on human basophil function by following changes in total cellular histamine and in vitro histamine-release induced by schistosome Ags or anti-IgE, in blood samples from infected Ugandan fishermen, who are continuously exposed to S. mansoni infection, before and 1-day and 21-days after PZQ treatment. Results There was a significant increase in the total cellular histamine in blood samples at 1-day post-treatment, followed by a very significant further increase by 21-days post-treatment. In vitro histamine-release induced by S. mansoni egg (SEA) or worm (SWA) Ags or anti-IgE antibody, was significantly reduced 1-day post-treatment. The degree of this reduction correlated with pre-treatment infection intensity. Twenty-1-days post-treatment, SEA-induced histamine-release was still significantly lower than at pretreatment. Histamine-release was not correlated to plasma concentrations of total or parasite-specific IgE, nor to specific IgG4 plasma concentrations. Conclusion The biology of human blood basophils is modulated by S. mansoni infection and praziquantel treatment. Infection intensity-dependent suppression of basophil histamine-release, histamine-dependent resistance to infection, and similarities with allergen desensitisation are discussed as possible explanations of these observations.
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Affiliation(s)
- Mohamed Z Satti
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
- Present Address: Department of Microbiology and Clinical Parasitology, College of Medicine and Medical Sciences, King Khalid University, P.O. Box 641 ABHA Saudi Arabia
| | - Pierre Cahen
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Per S Skov
- Reference Laboratory ApS, P.O. Box 590, Tagensvej 20 7512, DK 2200 Copenhagen N, Denmark
| | - Sarah Joseph
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Frances M Jones
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Colin Fitzsimmons
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Karl F Hoffmann
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Claus Reimert
- Danish Bilharziasis Laboratory, Jaegersborg Alle 1D, DK 2920 Charlottenlund, Denmark
| | - H Curtis Kariuki
- Division of Vector Borne Diseases, Kenyan Ministry of Health, P.O. Box 20750, Nairobi, Kenya
| | - Francis Kazibwe
- Vector Control Division, Ugandan Ministry of Health, P.O. Box 1661, Kampala, Uganda
| | - Joseph K Mwatha
- Kenya Medical Research Institute, P.O. Box 54840, Nairobi, Kenya
| | - Gachuhi Kimani
- Kenya Medical Research Institute, P.O. Box 54840, Nairobi, Kenya
| | - Birgitte J Vennervald
- Danish Bilharziasis Laboratory, Jaegersborg Alle 1D, DK 2920 Charlottenlund, Denmark
| | - John H Ouma
- Division of Vector Borne Diseases, Kenyan Ministry of Health, P.O. Box 20750, Nairobi, Kenya
| | - Narcis B Kabatereine
- Vector Control Division, Ugandan Ministry of Health, P.O. Box 1661, Kampala, Uganda
| | - David W Dunne
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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Lorenz I, Schneider EM, Stolz P, Brack A, Strube J. Influence of the diluent on the effect of highly diluted histamine on basophil activation. HOMEOPATHY 2003; 92:11-8. [PMID: 12587990 DOI: 10.1054/homp.2002.0082] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND In modern pharmaceutical practice, it is common to use purified ethanol and purified water for the preparation of homeopathic dilutions. Hahnemann in 1827 recommended good brandy as a diluent. Brandy contains a lot of accompanying substances in addition to ethanol. PURPOSE OF THE STUDY The research question was whether different diluents influence the effectiveness of high dilutions, especially above Avogadro's number. We compared two dilution media to investigate the diluent's influence. Within the limitations of the test-system, the dilution media were as similar to good brandy as possible and like purified ethanol. Dilutions of histamine were prepared with both media. As test-system, we used modified basophil activation in an in vitro cell system. Basophils are activated by anti-immunoglobulin E (anti-IgE). The activation of basophils is inhibited by prior incubation with histamine. The reduction in activation was measured with different dilutions of histamine. The test system used a 3-colour flow cytometric method. The interleukin-3 (IL-3) receptor CD123 was used to identify basophils in the leukocyte mixture. The CD63 surface marker was used for quantification of activated basophils. RESULTS With higher concentrations of histamine, we observed inhibition on optimally anti-IgE-stimulated basophil activation with a clear concentration dependency. With low concentrations of histamine (up to 10(-31)), we also observed inhibition of IgE-mediated basophil activation. Differences were observed between the dilution media. CONCLUSION The preliminary results support the hypothesis that the dilution medium may influence the effects of high dilutions. This could be of importance for homeopathic pharmaceutical practice as well as for ultra-high dilution experiments. The refined basophil test system proved to be highly sensitive and reliable. Further studies are needed.
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Affiliation(s)
- I Lorenz
- Forschungsinstitut KWALIS gGmbH, Dipperz, Germany.
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Affiliation(s)
- C Bachert
- Department of Oto-Rhino-Laryngolgoy, Ghent University Hospital, Belgium
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Ezeamuzie CI, Philips E. Histamine H(2) receptors mediate the inhibitory effect of histamine on human eosinophil degranulation. Br J Pharmacol 2000; 131:482-8. [PMID: 11015298 PMCID: PMC1572337 DOI: 10.1038/sj.bjp.0703556] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The effect of histamine on human eosinophil degranulation and the receptor mediating such effect were studied in vitro using the complement C5a-mediated eosinophil peroxidase (EPO) release model. Following pre-treatment with 5 microg ml(-1) cytochalasin B(CB), C5a induced a concentration-dependent release of EPO from eosinophils isolated from healthy donors. Histamine (0.1-50 microM), but not L-histidine, inhibited concentration-dependently C5a-induced EPO release with IC(50) (95% CI) of 0.6 microM (0.3-1.2 microM) and maximal inhibition of approximately 60%. A similar effect was seen with the selective H(2) agonists dimaprit (IC(50) (95% CI)=6.9 microM (3.2-10.6 microM)) and amthamine (IC(50) (95% CI)=0.4 microM (0.2-0.7 microM)). Neither the selective H(1) agonist 6-(2-(4-imidazolyl)ethylamino)-N-(4-trifluoromethylphenyl) heptanecarboxamide(HTMT), nor the selective H(3) agonists imetit (up to 100 microM) had any significant effect. The inhibition by histamine was reversed by cimetidine (0.1-30 microM) and other H(2) antagonists, but not the H(1) antagonist mepyramine (1.0- 100 microM), nor the H(3) antagonist thioperamide (1.0-100 microM). Cimetidine (1-30 microM) shifted to the right the dimaprit log dose-response curve, producing a pA(2) value of 5.9 and Schild's plot slope of 0.98, thus confirming simple competitive antagonism. Histamine (10-100 microM) increased intracellular level of adenosine 3',5'-cyclic monophosphate, which was completely abolished by cimetidine (30 microM), but not mepyramine or thioperamide. The cyclic AMP analogue - dibutyryl cyclic AMP - also inhibited degranulation (IC(50) approximately 300 microM). The cyclic AMP phosphodiesterase(PDE) IV inhibitor rolipram (10 microM) synergistically enhanced the inhibition of EPO release by histamine. These results suggest that histamine, via stimulation of H(2) receptors and a consequent elevation of intracellular levels of cyclic AMP, inhibits human eosinophil degranulation.
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Affiliation(s)
- C I Ezeamuzie
- Department of Pharmacology and Toxicology, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat, Kuwait.
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Abstract
Low-dose histamine therapy has been prescribed by otolaryngologists primarily to treat Bell's palsy, vestibular disorders, vascular headache, Ménière's attacks, and urticaria vasculitis. The scientific explanations for the usefulness of this once-empiric treatment are becoming more apparent. Two methods of establishing the appropriate dosages have emerged: the empiric, optimum-dosage approach and the objective, endpoint-titration approach. In this article, the author describes and recommends the latter approach. The author also reports on a 100-patient retrospective clinical study that revealed that the objective, endpoint-titration approach was effective in treating 80% of patients. In light of such success and the ease and economy of this treatment, low-dose histamine therapy appears to be a valuable clinical tool.
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Bertaccini G, Coruzzi G, Poli E. Functional role of histamine H3 receptors in peripheral tissues. PHARMACOCHEMISTRY LIBRARY 1998. [DOI: 10.1016/s0165-7208(98)80025-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Garrelds IM, de Graaf-in't Veld T, van Toorenenbergen AW, van Wijk RG, Boegheim JP, Saxena PR, Zijlstra FJ. Selective effect of levocabastine on histamine receptor and histamine release from human leukocytes and guinea pig isolated tissue. Ann Allergy Asthma Immunol 1996; 76:327-34. [PMID: 8612114 DOI: 10.1016/s1081-1206(10)60033-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Levocabastine is a potent histamine H1 receptor antagonist used topically in the treatment of patients with allergic rhinitis. It has been suggested that antihistamines also have anti-inflammatory properties. OBJECTIVE The present study was performed to investigate whether levocabastine, in addition to the anti-H1 receptor activity, has anti-inflammatory properties and thus is able to modulate the release of histamine and cytokines, such as interleukin 5 from human leukocytes and isolated tissues. METHODS Leukocytes suspensions were prepared by dextran sedimentation of peripheral venous blood drawn from allergic and healthy volunteers. Leukocytes obtained from allergic volunteers were preincubated for 30 minutes with levocabastine (doses 10(-8) M to 10(-6) M) and thereafter incubated with allergen. Leukocytes obtained from healthy volunteers were incubated for zero to three hours with levocabastine (doses 10(-14) M to 10(-3) M). Histamine release was measured by an automated fluorometric method. Interleukin-5 release was measured by enzyme linked immunoassay. Contractile responses to histamine on guinea pig trachea and lung parenchyma as well as the release of histamine and interleukin-5 by the tissues were investigated in the absence or presence of levocabastine and/or the histamine H2 receptor antagonist cimetidine. RESULTS Levocabastine did not influence allergen-induced histamine release from leukocytes obtained from allergic volunteers. High concentrations (10(-4)and 10(-3) M) of levocabastine, however, caused release of histamine from leukocytes obtained from healthy volunteers as well as guinea pig airway smooth muscle tissues. Pretreatment with levocabastine dose-dependently decreased the contractile response to histamine, showing an irreversible competitive mechanism. Interleukin 5 release from human leukocytes and by guinea pig airway smooth muscle was not detectable. CONCLUSIONS These findings indicate that the H1 receptor blocker, levocabastine, has probably no anti-inflammatory properties, measured as histamine release, and that the histamine release from both human leukocytes and guinea pig trachea and lung parenchyma is significantly increased by the drug only at high concentrations.
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Affiliation(s)
- I M Garrelds
- Department of Pharmacology, Faculty of Medicine, Erasmus University Rotterdam, The Netherlands
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Zuberbier T, Schwarz S, Hartmann K, Pfrommer C, Czarnetzki BM. Histamine releasability of basophils and skin mast cells in chronic urticaria. Allergy 1996; 51:24-8. [PMID: 8721524 DOI: 10.1111/j.1398-9995.1996.tb04545.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In order to clarify the pathogenetic role of basophils and mast cells in chronic urticaria, histamine and leukotriene (LT)C4 release was examined in washed mixed leukocytes (n = 8) and skin mast cells (n = 5) from patients with chronic urticaria and compared with the same cells from normal controls (n = 9). Anti-IgE-stimulated basophil histamine release was significantly reduced in urticaria patients (median 2.9% vs 15.1% in normal controls), whereas histamine release to A23187, FMLP, and PAF, as well as anti-IgE-induced LTC4 release, showed no differences in both groups. In contrast, anti-IgE-stimulated skin mast cells from urticaria patients reacted similarly to those of controls (median histamine release 11.4% vs 14.2% in normal controls). Pretreatment of the cells with interleukin (IL)-3 upregulated responsiveness of basophil histamine release to anti-IgE in urticaria patients (median histamine release 14.3%), but pretreatment with the H2-antagonist cimetidine showed no effect. These data show that reduced basophil histamine releasability in chronic urticaria is not H2 mediated. It is a stimulus-, mediator-, and cell type-restricted phenomenon that can, at least partially, be reversed in the presence of the cytokine IL-3.
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Affiliation(s)
- T Zuberbier
- Department of Dermatology, Virchow-Klinikum, Humboldt Universität zu Berlin, Germany
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Kohno S, Nakao S, Ogawa K, Yamamura H, Nabe T, Ohata K. Possible participation of histamine H3-receptors in the regulation of anaphylactic histamine release from isolated rat peritoneal mast cells. JAPANESE JOURNAL OF PHARMACOLOGY 1994; 66:173-80. [PMID: 7532731 DOI: 10.1254/jjp.66.173] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Anaphylactic histamine release from isolated rat peritoneal mast cells was concentration-dependently blocked by a 5-min treatment with exogenous histamine at 0.9 and 9 microM and enhanced by a 20- to 30-min treatment with thioperamide (H3-antagonist) at 3 microM with significance, but little affected by mepyramine (H1-antagonist) and cimetidine (H2-antagonist) at the cell concentration of 10(6) mast cells/ml. At a low concentration of mast cells (10(4) mast cells/ml), (R)-alpha-methylhistamine (alpha-MH), an H3-agonist, at 0.9-90 microM also inhibited the release in a concentration-dependent fashion. Thioperamide, but neither mepyramine nor cimetidine, significantly restored the decreased release by alpha-MH. However, the complete restoration by thioperamide could not be achieved because the drug itself slightly but concentration-dependently inhibited anaphylactic histamine release. On the other hand, not only betahistine and dimaprit but also alpha-MH did not suppress histamine release from the mast cells induced by compound 48/80. In rat plasma, considerable levels of histamine were detected. From these results, it is strongly suggested that histamine H3-like receptors are largely responsible for the negative feedback regulation of the anaphylactic histamine release from rat peritoneal mast cells.
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Affiliation(s)
- S Kohno
- Department of Pharmacology, Kyoto Pharmaceutical University, Japan
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Kleine-Tebbe J, Josties C, Frank G, Stalleicken D, Buschauer A, Schunack W, Kunkel G, Czarnetzki B. Inhibition of IgE- and non-IgE-mediated histamine release from human basophil leukocytes in vitro by a histamine H1-antagonist, desethoxycarbonyl-loratadine. J Allergy Clin Immunol 1994; 93:494-500. [PMID: 7509820 DOI: 10.1016/0091-6749(94)90359-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Loratadine, a new nonsedating histamine H1-antagonist, has been shown to inhibit immunologic release of inflammatory mediators in addition to its H1-receptor blocking properties. After oral administration, the agent is metabolized primarily to desethoxycarbonyl-loratadine (DCL). The basic piperidine, DCL, is readily soluble in water, whereas the nonbasic urethane, loratadine, is insufficiently soluble in water for some in vitro investigations. Therefore we used the metabolite, DCL, to study its influence on in vitro leukocyte histamine release (LHR) in 24 allergic and 22 nonallergic subjects. IgE-mediated and calcium ionophore A23187-induced LHR were inhibited by DCL in a dose-dependent fashion (values of drug concentration to induce 30% inhibition after stimulation with inhalant antigen, anti-IgE, concanavalin A, and calcium ionophore A23187 were 6, 8, 5, and 11 mumol/L, respectively). Higher concentrations of DCL caused mediator release in all subjects (n = 45, 30 mumol/L DC: 11% +/- 2% LHR, 100 mumol/L DCL: 35% +/- 1% LHR), abolishing any inhibitory effect of the drug. Rapid onset of inhibition by 10 mumol/L DCL was found in kinetic studies (n = 10). The inhibition of anti-IgE-induced histamine secretion was synergistically increased by simultaneous preincubation of DCL with the potent histamine H2-agonist, FRA-19. Additional data indicate that the inhibition of LHR by DCL might involve biochemical events that occur after cellular Ca++ influx because LHR induced by N-formyl-methionyl-leucyl-phenylalanine or the phorbol ester, 12-O-tetradecanoyl phorbol-12-acetate, was not significantly affected by DCL.
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Affiliation(s)
- J Kleine-Tebbe
- Clinic of Dermatology, University Hospital Rudolf Virchow, Freie Universität Berlin, Germany
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