TABLE 1

Potencies and efficacies of agonists at inducing βarr1 or βarr2 recruitment

When concentration-response curves did not reach saturation, the activation at the highest measured concentration is given as E_max. To analyze the data for preferred activation of βarr1 versus βarr2, two-way analysis of variance and the Bonferroni post-test were performed. *P < 0.05; **P < 0.01; ***P < 0.001; data ± S.D.; N ≥ 4.

Ligand	Stereo-Configuration	pEC₅₀βarr1	pEC₅₀βarr2	Statistical Significance	E_maxβarr1	E_maxβarr2	Statistical Significance
					%	%
ISO	(R)	7.38 ± 0.05	7.24 ± 0.03	ns	100	100	ns
	(S)	5.92 ± 0.07	5.66 ± 0.05	*	96.07 ± 2.54	94.22 ± 1.96	ns
EPI	(R)	6.66 ± 0.05	6.81 ± 0.05	ns	93.10 ± 1.78	94.42 ± 1.82	ns
NOR	(R)	4.64 ± 0.08	4.68 ± 0.10	ns	67.79 ± 2.08	76.20 ± 3.13	***
	(S)	No saturation	No saturation		56.01 ± 4.35	60.36 ± 7.21	*
DCI	Racemic	No signal	No signal		No signal	No signal
ALB	Racemic	6.32 ± 0.05	6.71 ± 0.07	***	16.58 ± 0.42	19.79 ± 0.51	ns
	(R)	6.55 ± 0.05	6.82 ± 0.09	***	19.59 ± 3.32	19.82 ± 1.92	ns
	(S)	4.77 ± 0.34	4.65 ± 0.10	ns	0.36 ± 0.05	3.45 ± 0.13	ns
FEN	Racemic	7.02 ± 0.06	7.04 ± 0.06	ns	63.94 ± 1.45	61.48 ± 1.51	ns
	(R,R′)	7.28 ± 0.07	7.20 ± 0.06	ns	70.56 ± 1.63	64.69 ± 1.48	***
	(R,S′)	5.78 ± 0.09	5.85 ± 0.05	ns	31.69 ± 1.17	29.27 ± 0.61	ns
	(S,R′)	4.48 ± 0.07	4.76 ± 0.07	***	11.20 ± 0.34	17.32 ± 0.48	***
	(S,S′)	4.49 ± 0.09	4.62 ± 0.06	ns	25.69 ± 1.02	28.71 ± 0.79	ns
SAL	Racemic	7.76 ± 0.09	7.83 ± 0.08	ns	10.35 ± 0.39	14.69 ± 0.46	**
	(R)	7.44 ± 0.07	7.42 ± 0.11	ns	10.90 ± 0.36	14.26 ± 0.69	ns
	(S)	6.79 ± 0.14	6.99 ± 0.11	***	3.90 ± 1.24	7.39 ± 1.88	***
FOR	Racemic	7.69 ± 0.06	7.63 ± 0.05	ns	76.80 ± 1.77	84.86 ± 1.78	***
	(R,R′)	7.95 ± 0.03	8.03 ± 0.08	ns	73.29 ± 0.96	80.33 ± 2.45	***
	(S,S′)	5.91 ± 0.07	5.82 ± 0.07	ns	65.13 ± 1.79	73.12 ± 2.03	***
OLO	(R)	8.11 ± 0.04	8.11 ± 0.08	ns	34.43 ± 0.58	34.49 ± 1.11	ns
	(S)	6.06 ± 0.07	6.00 ± 0.08	ns	31.15 ± 0.81	32.11 ± 1.08	ns
MDF	(R)	5.47 ± 0.08	5.89 ± 0.10	***	26.51 ± 0.94	26.35 ± 1.02	ns
	(S)	No saturation	No saturation		7.02 ± 0.23	14.52 ± 2.00	***
MEF	(R,R′)	7.00 ± 0.05	7.10 ± 0.05	ns	63.14 ± 1.31	61.18 ± 1.23	ns
	(R,S′)	6.03 ± 0.07	5.91 ± 0.06	ns	39.45 ± 1.02	42.48 ± 0.97	ns
	(S,R′)	No saturation	4.92 ± 0.07		3.17 ± 0.53	10.09 ± 0.32	***
	(S,S′)	No saturation	4.76 ± 0.08		3.64 ± 1.25	9.43 ± 0.39	***
MEtF	(R,R′)	6.36 ± 0.08	6.47 ± 0.05	ns	47.24 ± 1.67	40.37 ± 0.83	***
	(R,S′)	No saturation	No saturation		−0.04 ± 0.14	2.69 ± 0.21	ns
MnF	(R,R′)	No saturation	No saturation		5.75 ± 1.34	12.83 ± 0.98	***
	(R,S′)	No saturation	No saturation		−0.14 ± 0.13	3.15 ± 0.36	ns
MiF	(R,R′)	No signal	No signal		No signal	No signal
	(R,S′)	No saturation	No saturation		−0.01 ± 0.19	3.61 ± 0.26	ns
MNF	(R,R′)	6.6 ± 0.12	6.84 ± 0.06	**	34.04 ± 1.67	35.96 ± 0.88	ns
	(R,S′)	No saturation	6.39 ± 0.11		0.07 ± 0.17	2.17 ± 0.11	ns
	(S,R′)	No saturation	5.71 ± 0.07		9.42 ± 1.47	17.15 ± 0.47	***
	(S,S′)	No saturation	6.02 ± 0.39		−0.06 ± 0.11	0.75 ± 0.16	ns
ZIN	Racemic	7.62 ± 0.10	7.65 ± 0.07	ns	26.38 ± 1.07	28.22 ± 0.77	ns
BRL	Racemic	No saturation	6.26 ± 0.19		0.02 ± 0.23	1.52 ± 0.13	ns

BRL, BRL 37344; DCI, sodium dichloroisoproterenol; MDF, 4′-Methoxy-desmethylfenoterol; MEF, 4′-methoxyfenoterol; MEtF, 4′-methoxy-ethylfenoterol; MiF, 4′-methoxy-i-propylfenoterol; MnF, 4′-methoxy-n-propylfenoterol; NOR, norepinephrine; ns, not significant; OLO, olodaterol; ZIN, zinterol.