Characterization of interactions between local anesthetics and histamine H1 receptor by cell membrane chromatography model.

Local anesthetic has a wide application in clinical practice. However, angioedema, an adverse reaction caused by local anesthetics, has been reported to be related to histamine H1 receptor (H1R). Hence, an effective and practical method for investigating the interaction characteristics between local anesthetics and H1R is needed. In this work, the competition binding assay and the relative standard method based on H1R-HEK293/cell membrane chromatography (CMC) were developed to analyze the equilibrium dissociation constant (KD) values of local anesthetics with H1R. The activity of drugs toward H1R was evaluated by intracellular Ca2+ imaging assay. Molecular docking was used to verify the interaction modes that occurred at the activate pocket of H1R protein. Results showed that the local anesthetics can directly occupy histamine binding sites on H1R, and the KD values obtained from different CMC methods exhibited positive correlations with each other (p < 0.01). The KD values of tetracaine, procaine, and lidocaine were much closer to that of histamine than bupivacaine and ropivacaine. This was not only in line with the Ca2+ responses in activating H1R, but also consistent with the same amino acid residues shared with histamine in the H1R active site. In conclusion, this study provided new insight into the interactions between local anesthetics and H1R. The H1R-HEK293/CMC methods developed in this study could be used to evaluate the interaction characteristics of those compounds acting on H1R.