Figure 4.

Transactivation of EGFR after stimulation of α₁-adrenoceptor in endothelium-denuded rat thoracic aorta segments. Phosphorylation of EGFR (pEGFR) after phenylephrine (PE; 5 and 10 min) or EGF (10 min) stimulation in the absence and in the presence of EGFR tyrosine kinase inhibitor AG1478 (20 min pre-incubation) was determined by immunoblotting (A). The results from all of the experiments shown are representative of four independent experiments in isolated endothelium-denuded thoracic aorta segments from different rats. pEGFR was normalized to β-actin, quantified as the percentage of EGF (10 min)-induced pEGFR and expressed as mean ± SEM (B). *P < 0.05 versus phenylephrine alone at 5 min (Mann–Whitney U-test). pEGFR, phosphorylated epidermal growth factor receptor.