A method of identifying a compound capable of interacting with a G-Protein Coupled Receptor (GPCR) comprising: a) providing a device capable of measuring cell-substrate impedance; wherein said device is in the format of a multi-well plate, each well comprising a nonconductive substrate over which is fabricated a conductive electrode array, further wherein said device is operably connected to an impedance analyzer; b) adding test cells to at least two wells for attachment to said electrode array, wherein said test cells express a GPCR; c) determining first cell indices from first impedances, wherein said first impedances are cell-substrate impedances measured from said at least two wells immediately preceding step d), wherein the cell indices positively correlate with the number of viable cells in the wells, how well they are attached to the electrode surfaces, and the cell/electrode contact area due to the cell morphology status; d) adding a compound to at least one well containing said test cells to form at least one compound well and adding a vehicle control to at least another well containing test cells to form at least one control well; e) determining second cell indices from said second impedances, wherein said second impedances are cell-substrate impedances measured from said at least one compound well and said at least one control well after step d), wherein the cell indices positively correlate with the number of viable cells in the wells, how well they are attached to the electrode surfaces, and the cell/electrode contact area due to the cell morphology status; f) determining the change in cell index for said at least one compound well by comparing said second cell index of said at least one compound well to said first cell index of said at least one compound well, and determining the change in the impedance or cell index of said at least one control well by comparing said second cell index of said at least one control well to said first cell index of said at least one control well, g) comparing said change in cell index between said at least one compound well and said at least one control well; and h) identifying said compound interacts with said GPCR if said comparison demonstrates a significant difference between said change in cell index of said at least one compound well and said change in cell index of said at least one control well. a) providing a device capable of measuring cell-substrate impedance; wherein said device is in the format of a multi-well plate, each well comprising a nonconductive substrate over which is fabricated a conductive electrode array, further wherein said device is operably connected to an impedance analyzer; b) adding test cells to at least two wells for attachment to said electrode array, wherein said test cells express a GPCR; c) determining first cell indices from first impedances, wherein said first impedances are cell-substrate impedances measured from said at least two wells immediately preceding step d), wherein the cell indices positively correlate with the number of viable cells in the wells, how well they are attached to the electrode surfaces, and the cell/electrode contact area due to the cell morphology status; d) adding a compound to at least one well containing said test cells to form at least one compound well and adding a vehicle control to at least another well containing test cells to form at least one control well; e) determining second cell indices from said second impedances, wherein said second impedances are cell-substrate impedances measured from said at least one compound well and said at least one control well after step d), wherein the cell indices positively correlate with the number of viable cells in the wells, how well they are attached to the electrode surfaces, and the cell/electrode contact area due to the cell morphology status; f) determining the change in cell index for said at least one compound well by comparing said second cell index of said at least one compound well to said first cell index of said at least one compound well, and determining the change in the impedance or cell index of said at least one control well by comparing said second cell index of said at least one control well to said first cell index of said at least one control well, g) comparing said change in cell index between said at least one compound well and said at least one control well; and h) identifying said compound interacts with said GPCR if said comparison demonstrates a significant difference between said change in cell index of said at least one compound well and said change in cell index of said at least one control well.