{"title":"Histamine H<sub>1</sub>-receptor-mediated modulation of NMDA receptors signaling responses.","authors":"J-M Arrang, V Armand","doi":"10.1002/prp2.1216","DOIUrl":null,"url":null,"abstract":"<p><p>This study attempted to clarify the role of histamine H<sub>1</sub> receptors in epilepsy by exploring the effects of agonists and inverse agonists on the rundown of the current induced by iterative applications of NMDA or GABA in primary neuronal culture. Mepyramine, a classical H<sub>1</sub>-receptor antagonist/inverse agonist, increased the NMDA current by about 40% during the first minutes of recording. This effect was concentration-dependent, maximal at 10 nM, and mimicked by triprolidine, another antagonist/inverse agonist. No endogenous histamine was detected in the cultures by a selective immunoassay; both compounds were acting as inverse agonists. Indicating a high constitutive activity of the H<sub>1</sub> receptor in this system, histamine did not affect the NMDA rundown, including its settlement, but significantly reversed the effect of mepyramine. A similar pattern was obtained with 2,3 bromophenyl histamine, a selective H<sub>1</sub>-receptor agonist. The initial increase induced by the two inverse agonists was followed by the same rundown as in controls. H<sub>1</sub>- and NMDA receptors are colocalized in most cultured neuronal cells. Mepyramine and histamine did not affect the GABA rundown. Our findings suggest an interaction between H<sub>1</sub>- and NMDA receptors. Inactivation of the H<sub>1</sub>-receptor by its inverse agonists delays the settlement of the NMDA rundown, which may underlie their proconvulsant effect reported in clinics. Therefore, H<sub>1</sub>-receptor constitutive activity and the effect of histamine revealed in its absence, tend to facilitate the initiation of the rundown, which is consistent with the anticonvulsant properties of histamine via activation of H<sub>1</sub>-receptors reported in many studies.</p>","PeriodicalId":19948,"journal":{"name":"Pharmacology Research & Perspectives","volume":null,"pages":null},"PeriodicalIF":2.9000,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11458884/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Pharmacology Research & Perspectives","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1002/prp2.1216","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"PHARMACOLOGY & PHARMACY","Score":null,"Total":0}
引用次数: 0
Abstract
This study attempted to clarify the role of histamine H1 receptors in epilepsy by exploring the effects of agonists and inverse agonists on the rundown of the current induced by iterative applications of NMDA or GABA in primary neuronal culture. Mepyramine, a classical H1-receptor antagonist/inverse agonist, increased the NMDA current by about 40% during the first minutes of recording. This effect was concentration-dependent, maximal at 10 nM, and mimicked by triprolidine, another antagonist/inverse agonist. No endogenous histamine was detected in the cultures by a selective immunoassay; both compounds were acting as inverse agonists. Indicating a high constitutive activity of the H1 receptor in this system, histamine did not affect the NMDA rundown, including its settlement, but significantly reversed the effect of mepyramine. A similar pattern was obtained with 2,3 bromophenyl histamine, a selective H1-receptor agonist. The initial increase induced by the two inverse agonists was followed by the same rundown as in controls. H1- and NMDA receptors are colocalized in most cultured neuronal cells. Mepyramine and histamine did not affect the GABA rundown. Our findings suggest an interaction between H1- and NMDA receptors. Inactivation of the H1-receptor by its inverse agonists delays the settlement of the NMDA rundown, which may underlie their proconvulsant effect reported in clinics. Therefore, H1-receptor constitutive activity and the effect of histamine revealed in its absence, tend to facilitate the initiation of the rundown, which is consistent with the anticonvulsant properties of histamine via activation of H1-receptors reported in many studies.
期刊介绍:
PR&P is jointly published by the American Society for Pharmacology and Experimental Therapeutics (ASPET), the British Pharmacological Society (BPS), and Wiley. PR&P is a bi-monthly open access journal that publishes a range of article types, including: target validation (preclinical papers that show a hypothesis is incorrect or papers on drugs that have failed in early clinical development); drug discovery reviews (strategy, hypotheses, and data resulting in a successful therapeutic drug); frontiers in translational medicine (drug and target validation for an unmet therapeutic need); pharmacological hypotheses (reviews that are oriented to inform a novel hypothesis); and replication studies (work that refutes key findings [failed replication] and work that validates key findings). PR&P publishes papers submitted directly to the journal and those referred from the journals of ASPET and the BPS