. Author manuscript; available in PMC: 2009 Dec 3.

Published in final edited form as: Eur J Pharmacol. 2008 Oct 9;599(1-3):36–43. doi: 10.1016/j.ejphar.2008.09.043

Table 3.

Comparison of type-selectivity of opioid ligands for hMOR in present study with previously reported type-selectivities for hMOR in Toll et al. 1998 study. The degree of type-selectivity was determined by calculating the ratios of opioid K_i values for delta- vs. mu-selective and kappa- vs. mu-selective ligands.

Type-Selective Opioids	Present Study^a		Toll et al. 1998 ^b
Type-Selective Opioids	K_i (nM)	Ratio	K_i (nM)	Ratio
*Agonists*
DPDPE/DAMGO (delta/mu)	11,690/268	44	504/0.5	1,008
U-50,488/DAMGO (kappa/mu)	5,561/268	21	290/0.5	580
*Antagonists*
NTI/β-FNA (delta/mu)	6.10/1.85	3.2	6.3/0.3	21
Nor-BNI/β-FNA (kappa/mu)	67.4/1.85	35	21/0.3	70

Opioid ligand binding was conducted in intact cells in Hank's balanced salts buffer at pH 7.4

Opioid ligand binding was conducted using cell membrane homogenates in 50mM Tris-HCl pH 7.5.