Table 2. Compound Potency and Intrinsic Activity Derived from the Label-Free Whole-Cell Assay Performed on HEK293-hA_2AR Cells^a.

compound	pEC50	Emax, %
CGS21680	8.85 ± 0.08	100 ± 2
8	8.01 ± 0.22	66 ± 5
1	6.57 ± 0.37	41 ± 5
2	6.09 ± 0.23	–48 ± 5
3	7.35 ± 0.28	–50 ± 5
4	5.78 ± 0.38	37 ± 7
6	N.D.	N.D.

^aData are shown as mean ± S.E.M. of three independent experiments performed in duplicate. Log potency (pEC₅₀) and efficacy (E_max) were calculated from concentration–response curves derived from the peak analysis of CI changes. N.D., not determined.