Figure 3

The effects of morphine , naloxone,and endomorphin - 1 and endomorphin - 2 , on forskolin - induced cAMP levels . Functionality of the MOR expressed in U87 MG cells was determined using a forskolin-induced cAMP accumulation assay. (A) cAMP accumulation levels were determined in basal (untreated) U87 MG cells and in U87 MG cells treated with forskolin alone (75 μM), morphine alone (10 μM), forskolin (75 μM) + morphine (10 μM), or forskolin (75 μM) + morphine (10 μM) + naloxone (10 μM); (B) cAMP accumulation levels were determined in basal (untreated) U87 MG cells and in U87 MG cells treated with forskolin alone (75 μM), endomorphin-1 alone (10 μM), endomorphin-2 alone (10 μM), fosrkolin (75 μM) + endomorphin-1 (10 μM), forskolin (75 μM) + endomorphin-2 (10 μM), forskolin (75 μM) + endomorphin-1 (10 μM) + naloxone (10 μM), or forskolin (75 μM ) + endomorphin-2 (10 μM) + naloxone (10 μM). Data are the mean ± SE. A one-way ANOVA was used to determine significance. *P <0.05 compared to basal treatment; ^P <0.05 compared to forskolin treatment alone.