Table 1.

Affinities of opioid competitors in rpMOR- and hMOR-transfected CHO cells. The K_i for each competitor is reported in nM, and, for each competition curve, Hill slopes were determined using the sigmoidal dose-response (variable slope) curve-fitting program, GraphPad Prism (v.4.0).

rpMOR	Ki (nM)	S.E.M. (nM)	Hill Slope	S.E.M. (nM)	hMOR	Ki (nM)	S.E.M. (nM)	Hill Slope	S.E.M. (nM)	Ratioa
Agonists					Agonists
Morphine	390	± 67.0	−1.20	± 0.18	Morphine	611	± 48.0	−1.12	± 0.09	1.6#
DAMGO	2,914	± 615	−0.85	± 0.13	DAMGO	268	± 65.0	−0.85	± 0.15	0.1#
DPDPE	19,130	± 8,242	−0.93	± 0.24	DPDPE	11,690	± 2,886	−0.97	± 0.20	0.6
U-50488	8,421	± 1,509	−1.00	± 0.15	U-50488	5,561	± 1,985	−0.97	± 0.28	0.7
Antagonists					Antagonists
Naloxone	0.25	± 0.06	−1.19	± 0.13	Naloxone	0.76	± 0.21	−1.40	± 0.15	3.0#
β-FNA	0.63	± 0.15	−0.67	± 0.11	β-FNA	1.85	± 0.15	−1.01	± 0.09	2.9#
Naltrindole	2.96	± 0.56	−0.96	± 0.15	Naltrindole	6.10	± 1.00	−0.99	± 0.14	2.1
nor-BNI	14.4	± 3.35	−1.02	± 0.20	nor-BNI	67.4	± 19.6	−0.99	± 0.23	4.7#

^aThe ratio of the competitor K_i hMOR-transfected CHOs over that in rpMOR-transfected CHOs was determined

^#annotated where p<0.05 (unpaired, two-tailed Student's t-test).