TABLE 1.

G protein Δ6-G_qi4-myr-mediated Ca²⁺ release of HEK293 cells stably expressing opioid receptors

Data are mean ± S.E.M. (n = 3–6): one-way ANOVA and Tukey post-test.

	Log EC50				Emax
	Methadone	DAMGO	Morphine	DPDPE	Methadone	DAMGO	Morphine	DPDPE
					RFU
DOR	−5.2 ± 0.5*	−5.7 ± 0.1***	−6.0 ± 0.3	−7.8 ± 0.2	565 ± 32***	582 ± 55***	472 ± 40	741 ± 95
MOR	−6.7 ± 0.3	−7.5 ± 0.1	−7.4 ± 0.3	−4.6 ± 0.6##	1038 ± 88	735 ± 51	598 ± 36	N.D.
DOR/MOR	−6.9 ± 0.2	−7.7 ± 0.2	−7.2 ± 0.5	−7.8 ± 0.1	843 ± 76	956 ± 56	512 ± 45	734 ± 92

N.D., not determined.

^* P < 0.05 and

^*** P < 0.001 DOR compared with DOR/MOR or MOR;

^# P < 0.05 MOR compared with DOR or DOR/MOR.