Figure 5.

In vitro model of homologous β₂-adrenoceptor desensitization. (A) Concentration–response curves for salbutamol in human bronchial smooth muscle cells treated with vehicle (Ctrl) or homologously desensitized (Des) with salbutamol 1 µmol·L⁻¹ for 24 h. (B) Effect of homologous β₂-adrenoceptor desensitization on the in vitro responsiveness to 10 µmol·L⁻¹ salbutamol (Sal) or 1 µmol·L⁻¹ forskolin (Fsk). (C) Densitometric analyses of β₂-adrenoceptor. (D) RT-PCR image of peroxisome-proliferator-activated receptor (PPAR)γ gene expression and (E) a representative electrophoretic mobility shift assay gel showing the binding specificity of PPARγ to the DNA probe and a bar graph illustrating the densitometric analyses of PPAR-binding activity. Results are average of five separate experiments. Data are reported as mean ± standard error of the mean (SEM). *P < 0.05; ***P < 0.001.