Label-free versus conventional cellular assays: Functional investigations on the human histamine H receptor.

A set of histamine H receptor (HR) agonists and antagonists was characterized in functional assays, using dynamic mass redistribution (DMR), electric cell-substrate impedance sensing (ECIS) and various signaling pathway specific readouts (Fura-2 and aequorin calcium assays, arrestin recruitment (luciferase fragment complementation) assay, luciferase gene reporter assay). Data were gained from genetically engineered HEK293T cells and compared with reference data from GTPase assays and radioligand binding. Histamine and the other HR agonists gave different assay-related pEC values, however, the order of potency was maintained.