Effect of ODQ and milrinone on NE-stimulated cAMP accumulation of RBC from 6- to 18-day-old chick embryos. RBC were stimulated for 15 minutes with 10 μmol/L NE in the absence and presence of ODQ (30 μmol/L) and milrinone (20 μmol/L), respectively. Data are the mean values and SD from 3 to 5 experiments in each case.