Table 1.

K_i values Inhibition of μ, δ, and κ Opioid Binding to CHO Membranes

		Ki (nM) ± SE			Selectivity
Compound	Structure	[3H]DAMGO (μ)	[3H]Naltrindole (δ)	[3H]U69,593 (κ)	Kiδ/Kiμ	Kiδ/Kiκ	Kiμ/Kiκ
MCL 101a		0.23	5.9	0.079	26	75	2.9
Dmt-Ticb		894	1.6	37500	559c	23438d	42e
MCL 450		0.69±0.04	1.5±0.03	0.28±0.03	2.2	5.4	2.5
MCL 451		1100±33	4.2±0.58	62±0.82%*	262c	-	-

^*Maximum inhibition of [³H]U69,593 binding in the presence of 10 μM MCL 451.

^aData from Peng, X. et al. J. Med. Chem. 2006, 49, 256-262.

^bData from Pagé, D. et al. J. Med. Chem. 2001, 41, 2387-2390.

^cSelectivity K_i^μ/K_i^δ.

^dSelectivity K_i^κ/K_i^δ.

^eSelectivity K_ik/K_iμ.