Figure 4.
Changes in intracellular cAMP levels induced by rubiscolin-5, rubiscolin-6, and opioid compounds. Cells expressing MOR (A), DOR (B), or KOR (C) were treated with the listed compounds (10−11–10−5 M), and intracellular cAMP levels were measured with the cADDis® cAMP assay. Concentration–response curves were prepared by calculating cAMP levels relative to the data obtained with 10−5 M DAMGO for MOR (A), 10−5 M SNC-80 for DOR (B), and 10−5 M U-50488H for KOR (C). Data are presented as means ± S.E.M. for three independent experiments (n = 3–5).