Cultured vascular smooth muscle cells from porcine coronary artery possess A1 and A2 adenosine receptor activity

Abstract This study tested the hypothesis that an A1 adenosine receptor capable of inhibiting adenylate cyclase activity is present in porcine coronary vascular smooth muscle cells. In the absence of blockade of the A2 adenosine receptor, the A1 adenosine receptor agonists phenylisopropyladenosine (PIA) and cyclopentyladenosine (CPA) (10 −9 M) failed to inhibit Gpp(NH)p stimulated adenylate cyclase activity. However, after blockade of the A2 adenosine receptor with 30 nM CGS 15943A, cyclopentyladenosine (10 −9 M) inhibited Gpp(NH)p stimulated adenylate cyclase activity by 27±3% (4.3±0.7, Mean±SEM; pmoles/min/mg vs 5.9±0.8, P