Skip to main content
. Author manuscript; available in PMC: 2010 Dec 10.
Published in final edited form as: J Med Chem. 2009 Dec 10;52(23):7389–7396. doi: 10.1021/jm900379p

Table 3.

[35S]GTPγS Binding by uni- and bivalent ligands mediated by the kappa opioid receptor

Kappa Agonist Effects EC50 (nM) ± S.E.M. Emax (% stimulation) ± S.E.M. Functional activity
Butorphan 1.3 ± 0.44 80 ± 6.8 Agonist
9 2.8 ± 0.43 75 ± 1.1 Agonist
7a 4.9 ± 0.82 58 ± 7.4 Agonist
10 0.85 ± 0.053 65 ± 0.68 Agonist
4a 7.3 ± 1.6 54 ± 3.5 Agonist
4b 6.4 ± 0.87 60 ± 8.0 Agonist
11 1.6 ± 0.23 86 ± 7.3 Agonist
Kappa Antagonist Effects IC50 (nM) ± S.E.M. Imax (% inhibition) ± S.E.M.
Butorphan NT NT
9 No inhibition No inhibition
7a No inhibition No inhibition
10 No inhibition No inhibition
4a No inhibition No inhibition
4b No inhibition No inhibition
11 No inhibition No inhibition

To determine agonist effects, 12 different concentrations of the compounds were incubated with CHO cells that expressed the κ opioid receptor. Antagonist activity was determined by measuring the inhibition of [35S]GTPγS binding by the compounds. For antagonist studies, [35S]GTPγS binding was stimulated with 100 nM U50,488. The stimulation observed with U50,488 was set at 100% control binding.