Fig. 7. Dose-dependent effects of dibucaine of tetracaine on the expression of c-Fos induced with KCl. The cells were stimulated with 50 mM KCl for 60 min at 37°C after pretreatment with dibucaine or tetracaine for 10 min. c-Fos was detected as described in Materials and Methods. ( A, B ) Protein blots were probed with anti–c-Fos antibody. Typical results of three independent experiments are shown. ( C ) A densitmetric analysis of the phosphorylation of mitogen-activated protein kinase. Phosphorylation is expressed as a percentage of that caused by 50 mM KCl without pretreatment (positive control). Values are mean ± SEM of three independent experiments. The lower values at negative control (nc) represent the percentage of activity of nonstimulated cells.