. Author manuscript; available in PMC: 2008 May 2.

Published in final edited form as: J Med Chem. 2007 May 22;50(12):2779–2786. doi: 10.1021/jm061369n

Table 3.

Opioid Agonist Functional Activities in [³⁵S]GTPγS Binding Assays

	hDOR^a			rMOR^a
no.	log EC₅₀^b	EC₅₀ (nM)^c	E_max (%)^d	log EC₅₀^b	EC₅₀ (nM)^c	E_max (%)^d	EC₅₀(μ)/EC₅₀(δ)
1	−7.68 ± 0.20	21.	39 ± 2	−7.23 ± 0.18	59.	36 ± 2	2.8
2	−7.78 ± 0.36	17.	23 ± 2	−6.46 ± 0.38	350	24 ± 3	20
3	−7.30 ± 0.24	50.	34 ± 3	−7.38 ± 0.20	42.	36 ± 3	0.8
4	−8.09 ± 0.18	9.6	43 ± 2	−7.48 ± 0.16	33.	45 ± 3	3.4
5	−8.54 ± 0.21	2.9	45 ± 3	−7.50 ± 0.09	32.	42 ± 2	11
6	−8.73 ± 0.20	1.8	52 ± 3	−7.47 ± 0.12	34.	49 ± 2	19
7	−8.40 ± 0.11	4.0	130 ± 4	−7.56 ± 0.06	28.	120 ± 2	6.9
8	−6.44 ± 0.27	360	290 ± 28	−6.82 ± 0.08	150	114 ± 3	0.4
biphalin	−8.95 ± 0.17	1.1	83	—	—	—	—
DPDPE	−8.80 ± 0.25	1.6	69	—	—	—	—
DAMGO	—	—	—	−7.44 ± 0.19	37.	150	—

[³⁵S]GTP-γ-S binding analyses were carried out using membrane preparations from transfected cells that constitutively expressed the respective opioid receptor type.

The log EC₅₀ ± standard error are logarithmic values determined from the nonlinear regression analysis of data collected from two independent experiments.

The EC₅₀ value is converted from the respective log EC₅₀.

The E_max value is the saturable, maximum level of [³⁵S]GTP-γ-S binding in the cell membranes upon incubation with the peptide, expressed as [Net [³⁵S]GTP-γ-S bound/basal [³⁵S]GTP-γ-S bound] × 100 ± standard error.