Table 2.

Correlation of KOR affinity and KOR activity of 4 and U‐50,488.

Compd.	KOR[a] [3H]U‐69,593	cAMP[b]		β‐Arrestin‐2[c]
	K i±SEM [nM]	EC50 [nM]	E max [%][d]	EC50 [nM]	E max [%][d]
4	0.81±0.32	0.029	103	1.09	64
U‐50,488	0.34±0.07	0.16	100	7.85	100

[a] Guinea pig brain membrane preparations. [b] Human HEK 293T cells. [c] Human HTLA cells. [d] The E _max values refer to U‐50,488 (100 %).