Fig. 5: siRNAβ₂-AR or PTX blocked the endocytosis-promoting effect of β₂-AR/Gi-signaling pathway for β₁-AR.

A The effect of ICI118551 on β₁-AA-induced Ca²⁺ change in HL-1 cells after interfering with β₂-AR (siRNA β₂-AR). n = 3/group. Because the experiments in Fig. 4C and Fig. 5A were done at the same time, the same β₁-AA (WT) group in Fig. 4C were re-used as control here. B and C The effect of ICI118551 on β₁-AA restricting β₁-AR endocytosis in HL-1 cells which were transfected with siRNA β₂-AR. Scale bar = 10 μm. n = 3–6/group. C the β₁-AA (WT) group represented that β₁-AA stimulated β₁-AR overexpressed HL-1 cells. Because the experiments in Fig. 4E and Fig. 5C were done at the same time, the same β₁-AA (WT) group in Fig. 4E were re-used as control here. D The effect of ICI118551 on β₁-AA-induced Ca²⁺ change in HL-1 cells pretreated with PTX (1.5 μg/ml, 13 hours). n = 3/group. E, F The effect of ICI118551 on β₁-AA restricting β₁-AR endocytosis in HL-1 cells, which were pretreated with PTX. Scale bar = 10 μm. n = 3/group. G The effects of β₁-AA on intracellular Ca²⁺ when the HL-1 cells overexpressed β₂-AR-EYFP (β₂-AR OE) and pretreated with PTX. n = 3/group. H, I, The change of β₁-AR endocytosis caused by β₁-AA after the HL-1 cells overexpressing β₂-AR-EYFP (β₂-AR OE) and pretreated with PTX. Scale bar = 10 μm. n = 3/group. *P vs β₁-AA + PTX, P < 0.05. Data of C, F, and I were analyzed by two-way ANOVA with Bonferroni test. B, E and H were the representative images. C, F and I were the quantitative graphs, respectively.