Figure 3.

S1P receptor antagonists attenuate phosphorylation responses of ERK1/2 in HUVEC induced by COA-Cl and S1P. The figure shows the results of immunoblot (IB) analyses in which HUVEC were treated with COA-Cl or S1P either in the presence or absence of pretreatment with antagonists specific for S1P receptors. (A) Effects of the S1P₁ antagonist W146. HUVEC were treated with 10 μmol/L of W146 for 30 min, followed by 100 μmol/L of COA-Cl for 15 min. They were then subjected to IB analyses for phospho- and total-ERK1/2. The upper half of the panel shows the representative results of four independent experiments, which yielded equivalent data. The results are summarized in the lower half graphs. (B) VPC23019, a dual antagonist for S1P₁/S1P₃ (5 μmol/L for 15 min), was used instead of W146 (n = 6). (C and D) Cells were treated with 1 μmol/L of S1P for 5 min instead of COA-Cl (n = 4), respectively. *P < 0.05 versus vehicle alone. †P < 0.05 versus cells not treated with W146 or VPC23019.