h at room temperature binding reactions are terminated by rapid filtration onto 96 well unifilter gf c filter plates perkin elmer shelton conn presoaked in 0 5 polyethylenimine sigma harvesting is performed using a 96 well tissue harvester perkin elmer shelton conn followed by three filtration washes with 500 u03bcl ice cold binding buffer filter plates are subsequently dried at 50 u00b0 c for 2 3 hours fifty u03bcl well scintillation cocktail perkin elmer shelton conn is added and plates are counted in a packard top count for 1 min well the data from screening and dose displacement experiments are analyzed using microsoft excel and the curve fitting functions in graphpad prism u2122 v 3 0 or higher respectively or an in house function for one site competition curve fitting certain compounds of the invention have a k i nm of about 5000 or less in one embodiment certain compounds of the invention have a k i nm of about 1000 or less in one embodiment certain compounds of the invention have a k i nm of about 500 or less in other embodiments the compounds of the invention have a k i nm of about 300 or less or of about 100 or less or of about 50 or less or of.