Figure 6.

Effects of various endothelial GPCR antagonists for COA-Cl-induced ERK1/2 phosphorylation responses. The figure shows the results of immunoblot (IB) analyses, in which HUVEC were treated with COA-Cl or with various endothelial agonists/antagonists. Panel A shows the effects of KW-3902, an antagonist for adenosine A₁ receptor. The cells were treated with KW-3902 (20 μmol/L for 30 min), followed by COA-Cl (100 μmol/L for 15 min, left half) or adenosine (10 μmol/L for 10 min, right half). Panel B shows the effects of MRS2179, an antagonist for purinergic P2Y₁ receptor. The cells were treated with MRS2179 (100 μmol/L for 30 min), followed by COA-Cl (left half) or ADP (1 μmol/L for 15 min, right half). (C) Effects of ginkgolide B, an antagonist for PAF-R. The cells were treated with ginkgolide B (1 μmol/L for 30 min), followed by COA-Cl (left half) or PAF (5 μmol/L for 5 min, right half). HUVEC lysates were probed with antibodies directed to phospho- or total-ERK1/2 as described above. In each set of experiments, the receptor antagonist was capable of effectively attenuating responses elicited by its cognate agonist, without affecting responses elicited by COA-Cl (n = 3) for each subset.