Table 2

Functional Parameters of WT, R3, B2, B3, and R3B3 coupling to G_i and G_s

	G_iCoupling		G_S Coupling
	Max Inhibition	EC₅₀	Max Stimulation	EC₅₀
	%	nM	% over control	nM
WT	85	0.15	160	41
R3	87	0.2	100	240
B2	82	3.0	180	39
B3	71	7.4	80	240
R3B3	64	28	20	190

[³H]cAMP accumulation assays were performed on whole cells that had been pretreated with (G_S coupling) or without (G_i coupling) PTX. Cells were incubated with increasing concentrations of UK 14,304 for 30 minutes at 37° in the presence of 1 mM IBMX and 30 μM forskolin. Maximum responses and EC₅₀values were determined from dose response curves. Data are from three or four separate experiments performed in duplicate.