Table 1.

Binding Affinity and In Vitro Activity for Compounds 8, 9, 11, and 13 and Reference Compounds

	bioassay IC50a(nM)		binding Kia,b (nM)
cmpds	MVD	GPI/LMMP	hDOR	hMOR	KOR
cDADAE (8)	0.59 ± 0.19	5.3 ± 0.21	0.43 ± 0.16	1.35 ± 0.45	576 ± 23
tDADAE (9)	0.76 ± 0.070	5.2 ± 0.61	0.57 ± 0.21	1.30 ± 1.2	74.8 ± 5.1
rDADAE (11)	3.4 ± 0.60	59 ± 24	7.9 ± 0.61	56.9 ± 3.5	3960 ± 210
lDADAE (13)	5.7 ± 1.1	34 ± 11	8.1 ± 0.22	64.5 ± 4.1	3870 ± 185
H-Tyr-c[D-Cys-Gly-Phe-D-Cys]-Xc	0.12	1.48	0.822	0.550	44.9
DPDPEd	4.1 ± 0.46	7300 ± 1700	1.6 ± 0.2	609 ± 70

^aDisplacement of [³H]DAMGO (μ -selective) and [³H]DPDPE (δ-selective) from rat brain membrane binding sites; displacement of [³H]U69593 (κ-selective) from guinea pig brain membrane binding sites.

^b±S.E.M.

^cMVD and GPI data refers to H-Tyr-c[D-Cys-Gly-Phe-D-Cys]-X^c (X = OH) according to ref 4a and hDor, hMor, and Kor data refers to H-Tyr-c[D-Cys-Gly-Phe-D-Cys]-X^c (X = NH₂) according to ref 12a.

^dData according to ref 19b.