Table 1

In vitro opioid activity profiles of MOR, DALDA, and [Dmt¹]DALDA (Schiller et al., 2000)

Compound	Opioid Receptor Binding^1-a		GPI^1-bIC₅₀	MVD^1-b IC₅₀
Compound	K_i^μ	K_i^δ	GPI^1-bIC₅₀	MVD^1-b IC₅₀	K_i^κ	K_i^δ/ K_i^μ	K_i^κ/ K_i^μ
	nM	nM	nM			nM	nM
MOR	1.00 ± 0.04	32.6 ± 3.7	217 ± 49	32.6	217	29.3 ± 2.2	155 ± 31
DALDA	1.69 ± 0.25	19,200 ± 2,000	4,230 ± 360	11,400	2,500	254 ± 27	781 ± 146
[Dmt¹]DALDA	0.143 ± 0.015	2,100 ± 310	22.3 ± 4.2	14,700	156	1.41 ± 0.29	23.1 ± 2.0

↵1-a Binding affinities for μ-, δ-, and κ-receptors were determined by displacing, respectively, [³H]DAMGO (H-Tyr-d-Ala-Gly-N-Me-Phe-Gly-ol), [³H]DSLET (H-Tyr-d-Ser-Gly-Phe-Leu-Thr-OH), and [³H]U69,593 from rat or guinea pig brain membrane binding sites, as reported elsewhere (Schiller et al., 1978,2000).
↵1-b The agonist potencies of the three compounds were determined in the guinea pig ileum assay and in the mouse vas deferens assay as reported elsewhere (Schiller et al., 1978; DiMaio et al., 1982).