TABLE 3

Binding parameters obtain from [³H]DAMGO, [³H]U69593, and [³H]diprenorphine saturation binding curves performed in MOR, KOR single expressing-, and MOR-KOR-coexpressing cell membranes

Data are presented as mean ± S.E.M.; n = 3.

Receptor	[³H]DAMGO		[³H]U69593		[³H]Diprenorphine
Receptor	B_max	K_d	B_max	K_d	B_max	K_d
	fmol/mg	nM	fmol/mg	nM	fmol/mg	nM
MOR	263 ± 16	2.9 ± 0.5	N.D.	N.D.	1035 ± 130	0.3 ± 0.1
KOR	N.D.	N.D.	1023 ± 140	6.8 ± 1.8	1465 ± 177	0.3 ± 0.1
MOR-KOR	774 ± 181	17 ± 6^**	1235 ± 81	3.0 ± 0.5	2915 ± 230	0.5 ± 0.1

N.D., not determined.
↵** P < 0.01, t test; compared with MOR.