Table 1 Activation Profile of Opioid ligands in HEK-δ Cells

Butorphanol

61 ± 12

64 ± 4^$

Cyclazocine

6 ± 3

53 ± 2**

Dezocine

477 ± 152

39 + 8

Etorphine

0.2 ± 0.1

67 ± 3^$$

Fentanyl

2039 ± 554

71 ± 7^{$$ #}

Hydromorphone

54 ± 31

65 ± 5^$

Lofentanil

0.8 ± 0.4

62 ± 7^$

Metazocine

159 ± 70

77 ± 4^$$

Met-enkephalin

22 ± 17

49 ± 6^##

Morphine

1101 ± 614

39 ± 4**

Nalbuphine

545 ± 378

55 ± 7*

Nalorphine

Antagonist

Naltrexone

Antagonist

SKF 10047

184 ± 121

68 ± 9^$$

WIN 44,441

40 ± 25

54 ± 6*

Xorphanol

8 ± 2

76 ± 4^{$$ ##}