Miniaturization of whole live cell-based GPCR assays using microdispensing and detection systems

Cell-based beta-lactamase reporter gene assays designed to measure the functional responses of G-protein-coupled receptors (GPCRs) were miniaturized to less than 2 microL total assay volume in a 3456-well microplate. Studies were done to evaluate both receptor agonists and antagonists. The pharmacology of agonists and antagonists for target GPCRs originally developed in a 96-well format was recapitulated in a 3456-well microplate format without compromising data quality or EC(50)/IC(50) precision. These assays were employed in high-throughput screening campaigns, allowing the testing of more than 150,000 compounds in 8 h. The instrumentation used and practical aspects of the assay development are discussed.