Fig. 3. Levels of tyrosine phosphorylation of epidermal growth factor receptor (EGFR) in the human corneal epithelial cell with or without lidocaine (4 μm –40 μM). The cells were incubated for 5 min with epidermal growth factor (EGF), lidocaine, or both. Equal amounts of human corneal epithelial cell protein were immunoprecipitated (IP) and immunoblotted (IB) with antiphosphotyrosine (pY) or anti-EGFR antibody. Solid bars  represent basal and EGF-stimulated levels of tyrosine phosphorylation as a percent of EGF-stimulated phosphorylation without lidocaine (100%). EGF-stimulated tyrosine phosphorylation of EGFR (IP: EGFR; IB: pY) was attenuated by lidocaine (expressed as percent phosphorylation normalized to EGFR protein level). EGFR protein content (IP: EGFR; IB: EGFR) was not altered by the addition of lidocaine. Results displayed in the upper panels  represent typical immunoblots of autophosphorylation of EGFR and immunoblots of protein content. *P < 0.05 and **P < 0.01 versus  EGF-stimulated tyrosine phosphorylation without lidocaine; n = 4 for each lane.