We have tested the existence of functional A(2A) adenosine receptor in porcine coronary artery using, for the first time, the new A(2A) antagonist ZM241385. Nonselective agonist NECA and A(2A)-selective agonist CGS21680 produced concentration-dependent relaxation of prostaglandin F(2)α, (PGF(2α))precontracted endothelium intact (E+) and denuded (E-) rings. Relaxation was significantly greater in E+ rings than in E-rings. A(2A) adenosine receptor-selective antagonist, ZM241385 (10-6 M), significantly attenuated the relaxation responses. The antagonism of ZM241385 was compared with that of SCH58261 (10-6 M), another A(2A) adenosine receptor-selective antagonist, which also significantly attenuated the relaxation response to both agonists. However, ZM241385 produced a significantly greater shift of the relaxation-response curves to the right compared with SCH58261 both in E+ and E- rings. The data show for the first time that ZM241385 is a potent A(2A)-receptor antagonist in porcine coronary artery and a useful tool to study A(2A)-receptor function.
- A adenosine receptors
- Porcine coronary artery relaxation
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine