Table 1.

Antagonist potency (fpKi values) for the antagonists at opioid receptors

	MOPr	DOPr	KOPr	NOPr
GSK1521498	9.64 ± 0.06	8.50 ± 0.03	8.48 ± 0.14	6.59 ± 0.13
Naloxone	8.68 ± 0.14	7.51 ± 0.16	7.50 ± 0.16	<5
Naltrexone	9.15 ± 0.13	8.26 ± 0.10	8.78 ± 0.07	<5
6β-Naltrexol	8.72 ± 0.11	7.71 ± 0.10	8.52 ± 0.05	<5
Nalmefene	9.62 ± 0.12	8.08 ± 0.06	–	<5

Data are presented as mean ± SEM of three experiments