Table 1.

Pharmacology of opioid receptor subtype for 130 pS channel activation

Drugs tested	Cells tested	Cells with channel (%)
Endomorphin-1 (0.5 μM)	51	25 (49)
Endomorphin-1 (0.5 μM) + CTOP (0.1 μM)	42	3 (7)*
Endomorphin-1 (0.5 μM) + ICI-174864 (0.5 μM)	20	10 (50)
Endomorphin-1 (0.5 μM) + nor-binaltorphimine (0.1 μM)	21	10 (48)
DPDPEV (1 μM)	16	1 (6)
U-50,488 (5 μM)	19	0 (0)

CTOP, d-phe-cys-tyr-d-trp-orn-thr-pen-thr-NH₂; DPDPE, [d-pen², d-pen⁵]-enkephalin. Pen, penicillamine; Orn, ornithine. 

^*P < 0.001 vs. endomorphin-1 alone.