Table 2. Functional Potencies and Efficacies of Ligands: Agonism and inactivation of Human α4β2-nAChRs.^a.

	agonism				inactivation
compd	EC50 (nM)	pEC50	HS-α4β2 efficacy (%)	LS-α4β2 efficacy (%)	IC50 (nM)	pIC50	efficacy (%)
1b	5.8		100		4.8		63
2c	18		60		5.6		71
9	14	7.9 ± 0.10	76 ± 14	0.40 ± 5.1	11	8.0 ± 0.04	77 ± 1.0
10	>1000	<6.0	NDd	ND	>103	<6.0	ND
13	18	7.8 ± 0.10	100 ± 7.0	1.7 ± 4.0	15	7.8 ± 0.04	73 ± 2.0
15	25	7.6 ± 0.10	110 ± 7.0	–9.4 ± 4.0	20	7.7 ± 0.04	74 ± 2.0
18	20	7.7 ± 0.10	88 ± 4.0	–7.0 ± 4.0	12	7.9 ± 0.10	76 ± 4.0
nicotine	300	6.5 ± 0.10	120 ± 9.0	70 ± 6.0	430	6.4 ± 0.10	92 ± 2.0

^aSee Supporting Information for details. The term “inactivation” is used because compounds may be acting to desensitize receptors or as competitive or noncompetitive antagonists, and further work is needed to make such a distinction. Potencies (EC₅₀ or IC₅₀ values) and efficacies were measured for actions at a mixture of high-sensitivity (HS) and low-sensitivity (LS) α4β2-nAChRs. Reported errors are the standard error of the mean (SEM) for all values.

^bResults for compound 1 were obtained from ref (18).

^cResults for compound 2 were obtained from ref (20).

^dND: Not determined. The efficacy was not determined if the EC₅₀ or the IC₅₀ value was greater than 1000 nM.