Figure 6.

Dose-Dependent Binding of Prop-BY630 to β₂-Adrenoceptors and Subsequent Ligand Dissociation In Vivo

To monitor fluorescent ligand dissociation over time in the primary tumors, mice were administered with 3 different doses of propranolol-(β-Ala-β-Ala)-X-BY630/650 (0.01, 0.03, or 0.1 mg/kg; IT). At 1, 24, 48, and 72 hr after fluorescent ligand injection, mice were injected with furimazine substrate (IV, 100 μL in PBS, circa 0.37 mg/kg) and imaged 5 min later using the IVIS Lumina II camera system. Imaging was performed by capturing sequential luminescence (open channel, 30 s exposure time) and fluorescence (Cy5.5 channel, 5 min exposure times) images. All mice were also imaged on the day before fluorescent ligand injection following an IV injection of furimazine to determine luminescence (and BRET) baseline (t = 0). Data represent mean ± SE of 6 mice in each group. *p < 0.05. **p < 0.01 or ^#p < 0.001 compared with corresponding time 0 controls. Two-way ANOVA with repeated measures and Dunnett multiple comparisons.