2. Academic Validation
  3. Investigation of the Binding Characteristics of Agonists and Various Antagonists Targeting Histamine 1 Receptor

Investigation of the Binding Characteristics of Agonists and Various Antagonists Targeting Histamine 1 Receptor

  • Pharm Res. 2025 Aug;42(8):1315-1329. doi: 10.1007/s11095-025-03899-z.
Panpan Lei 1 2,  Yuxiu Zhang 1 2,  Xiaoyu Ma 1 2,  Sifan Xie 1 2,  Jiapan Gao 1 2,  Bingxi Ren 1 2,  Yuanji Wang 3,  Weina Ma 4 5
Affiliations

Affiliations

  • 1 School of Pharmacy, Health Science Center, Xi'an Jiaotong University, No.76, Yanta West Street, #54, Xi'an, Shaanxi Province, 710061, People's Republic of China.
  • 2 State Key Laboratory of Shaanxi for Natural Medicines Research and Engineering, Xi'an, 710061, People's Republic of China.
  • 3 Department of Pharmacy, The First Affiliated Hospital of Northwest University, Xi'an, 710002, People's Republic of China.
  • 4 School of Pharmacy, Health Science Center, Xi'an Jiaotong University, No.76, Yanta West Street, #54, Xi'an, Shaanxi Province, 710061, People's Republic of China. maweina2015@xjtu.edu.cn.
  • 5 State Key Laboratory of Shaanxi for Natural Medicines Research and Engineering, Xi'an, 710061, People's Republic of China. maweina2015@xjtu.edu.cn.
PMID: 40760405 DOI: 10.1007/s11095-025-03899-z
Abstract

Objective: The histamine H1 receptor (H1R) plays a central role in mediating allergic responses, making it a critical target for therapeutic intervention. However, the molecular mechanisms underlying drug binding to H1R remain incompletely elucidated.

Methods: We employed an integrated approach combining site-directed mutagenesis, cell membrane chromatography (CMC) and pharmacological activity assays to systematically characterize the binding mechanisms of H1R agonists and antagonists. We constructed various H1R/CMC systems using high-expression H1R cells (wild type, TM3, TM5, TM6, and ECL2 mutants) and evaluated the binding affinities of three agonists (histamine, HTMT, betahistine) and three classes of antagonists (ethylenediamine/propanamine, tricyclic, piperidine derivatives).

Results: Our findings reveal distinct agonist binding preferences: histamine primarily targets TM3, HTMT interacts with TM5, and betahistine shows a strong preference for TM6. Among antagonists, ethylenediamine/propanamine and piperidine classes predominantly block TM3 and TM6 regions, while tricyclic antagonists additionally depend on TM5 region for their inhibitory effects. Pharmacological validation through Phospholipase C (PLC) activity assays corroborated these results, demonstrating that mutations in specific transmembrane domains significantly alter agonist-induced signaling and antagonist-mediated efficacy.

Conclusion: These mechanistic insights into H1R ligand binding provide a structural foundation for the rational design of targeted therapies with improved selectivity and efficacy against allergic disorders.

Keywords

binding characteristics; cell membrane chromatography; equilibrium dissociation constant; histamine 1 receptor; phospholipase C.

Figures
Products