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Published on: April 19, 2011
The A2A adenosine receptor mediates coronary vasodilation
L Belardinelli1, J C Shryock, S Snowdy
1Department of Medicine, College of Medicine, University of Florida, Gainesville, USA. ramsepd@medicine.ufl.edu
The Journal of Pharmacology and Experimental Therapeutics
|March 13, 1998
Summary
The A2A adenosine receptor (A2AAdoR) significantly mediates coronary vasodilation from adenosine. This study confirms A2AAdoRs
Area of Science:
- Cardiovascular Pharmacology
- Adenosine Receptor Signaling
Background:
- Adenosine-induced coronary vasodilation is mediated by A2 adenosine receptors (A2AdoRs).
- The specific subtype (A2A and/or A2B) responsible for this vasodilation remains uncertain.
Purpose of the Study:
- To investigate the role of A2A adenosine receptors (A2AAdoRs) in mediating coronary vasodilation caused by exogenous and endogenous adenosine in guinea pig hearts.
- To test the hypothesis that A2AAdoRs are the primary mediators of this effect.
Main Methods:
- Utilized the selective A2AAdoR antagonist SCH58261 to block A2AAdoRs.
- Measured coronary conductance changes and atrioventricular nodal conduction time in response to adenosine and selective receptor agonists.
- Determined the concentration-dependent and competitive antagonism of SCH58261.
Main Results:
- SCH58261 competitively antagonized CGS21680-induced coronary vasodilation (KB = 5.01 nM).
- SCH58261 reversed vasodilation induced by adenosine and selective A2AAdoR agonists, but not by sodium nitroprusside or diltiazem.
- SCH58261 did not affect A1AdoR-mediated effects on atrioventricular nodal conduction.
Conclusions:
- The A2AAdoR plays a major role in mediating coronary vasodilation induced by exogenous and endogenous adenosine.
- Findings support A2AAdoRs as key players in adenosine-related coronary blood flow regulation.
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