Effect of the activation of the dopamine D1 receptor and adrenergic α1A receptor on ERK and PEBP phosphorylation in HEK293 cells. (A) HEK293/D1 cells were treated with 1 μM dopamine for the indicated time intervals. (B) HEK293/α1A cells were treated with 1 μM PE for the indicated time intervals. One-way analysis of variance was used followed by Dunnett’s post hoc test. For pERK, *P<0.05, **P<0.01 and ***P<0.001, compared with the Con; for pPEBP, #P<0.05 and ##P<0.01, compared with the Con. (C and D) HEK293/α1A cells were pretreated with 1 μM Gö6983 or vehicle (dimethyl sulfoxide) for 30 min and were then stimulated with 1 μM PE for 30 min. Two-way analysis of variance was used followed by the Bonferroni post hoc test. *P<0.05 and ***P<0.001, compared with each Con. Student’s t-test was used for the ERK activity comparison with or without Gö6983 (##P<0.01). All data are presented as the mean ± standard error of the mean from three independent experiments. PEBP, phosphatidylethanolamine-binding protein; PE, phenylephrine; ERK, extracellular signal-regulated kinase; CHO cells, Chinese hamster ovary cells; HEK, human embryonic kidney; Con, control.