. Author manuscript; available in PMC: 2012 Oct 13.

Published in final edited form as: J Med Chem. 2011 Sep 7;54(19):6531–6537. doi: 10.1021/jm2003238

Table 1.

Binding affinities to opioid and NOP receptors.

	Ki (nM) ± SEM^a
	NOP	MU	DELTA	KAPPA
Nociceptin	0.08 ± 0.03	437 ± 13	2846 ± 512	147 ± 3.4
DAMGO	> 10,000	1.59 ± 0.17	300 ± 59	306 ± 46
DPDPE	> 10,000	504 ± 10	1.24 ± 0.09	> 10,000
U69,593	> 10,000	> 10,000	> 10,000	1.6 ± 0.26
1a	77.4 ± 16	1.5 ± 0.8	6.1 ± 0.4	2.5 ± 1.2
1b	8.46 ± 1.3	2.14 ± 0.79	1.59 ± 0.28	5.63 ± 1.3
1c	18.5 ± 0.68	2.95 ± 0.65	1.27 ± 0.21	1.59 ± 0.25
1d	22.0 ± 0.55	2.19 ± 0.65	3.66 ± 0.92	4.15 ± 1.3
1e	133 ± 8.2	5.56 ± 1.3	3.03 ± 0.61	8.92 ± 0.34
1f	16.0 ± 1.5	11.4 ± 0.17	7.13 ± 1.3	9.87 ± 1.3
6a	237 ± 64	14.3 ± 0.88	6.79 ± 0.99	9.93 ± 3.7
6b	67.8 ± 20	13.2 ± 0.97	17.2 ± 0.26	45.6 ± 3.4
7	159 ± 1.4	10.5 ± 3.86	8.67 ± 0.81	35.5 ± 3.9

Binding to cloned human opioid receptors transfected into CHO cells (method in ref 25). Values are the average of two experiments each carried out in duplicate. Tritiated ligands were [³H]DAMGO (MOP), [³H]Cl-DPDPE (DOP), [³H]U69593 (KOP) and [³H] N/OFQ