Characterization of interactions between local anesthetics and histamine H 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 H receptor (HR). Hence, an effective and practical method for investigating the interaction characteristics between local anesthetics and HR is needed. In this work, the competition binding assay and the relative standard method based on HR-HEK293/cell membrane chromatography (CMC) were developed to analyze the equilibrium dissociation constant (K) values of local anesthetics with HR. The activity of drugs toward HR was evaluated by intracellular Ca imaging assay. Molecular docking was used to verify the interaction modes that occurred at the activate pocket of HR protein. Results showed that the local anesthetics can directly occupy histamine binding sites on HR, and the K values obtained from different CMC methods exhibited positive correlations with each other (p < 0.01). The K 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 Ca responses in activating HR, but also consistent with the same amino acid residues shared with histamine in the HR active site. In conclusion, this study provided new insight into the interactions between local anesthetics and HR. The HR-HEK293/CMC methods developed in this study could be used to evaluate the interaction characteristics of those compounds acting on HR.