HIGH-THROUGHPUT ASSAYS OF CLONED ADRENERGIC, MUSCARINIC, NEUROKININ, AND NEUROTROPHIN RECEPTORS IN LIVING MAMMALIAN-CELLS

Many receptors stimulate proliferation of NIH 3T3 cells in a ligand de pendent fashion. Based on this observation, we developed a high throug hput assay of cloned receptor pharmacology. In this assay, receptors a re transiently co-expressed with the marker enzyme beta-galactosidase. Receptors that induce cellular proliferation select and amplify the c ells that also express the marker, thus the ability of ligands to alte r receptor activity are reported as changes in enzyme activity In the present study, we used this assay to evaluate the ability of agonist l igands to stimulate four cloned receptors. The agonists phenylephrine, carbachol, substance P and nerve growth Factor selectively stimulated cells transfected with the alpha-1b adrenergic, m4 muscarinic, NK1 ne urokinin and trkA neurotrophin receptors, respectively. These data dem onstrate that a high throughput colorimetric assay performed in 96 wel l plates can be used to evaluate the pharmacology of ligands for clone d receptors belonging to a wide range of functional and pharmacologica l classes.