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Adenosine A2a/b receptor‐mediated vasodilation is antagonized by adenosine A1 receptor in coronary circulation of healthy Ossabaw swine
Author(s) -
Neeb Zachary Paul,
Long Xin,
Mokelke Eric,
Edwards Jason,
Alloosh Mouhamad,
Sturek Michael
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.1032.9
Subject(s) - adenosine , vasodilation , adenosine receptor , medicine , coronary circulation , adenosine a1 receptor , agonist , ccpa , cgs 21680 , endocrinology , cardiology , pharmacology , receptor , blood flow
Adenosine clearly plays a role in mediating coronary blood flow. However, contributions of specific adenosine receptor subtypes A1, A2a, and A2b (A1R, A2aR, and A2bR) to changes in coronary flow in swine have not been elucidated. Adenosine receptors (AR) are G‐protein coupled, and inhibit (A1R, G i ) or stimulate (A2a/bR, G s ) adenylyl cyclase. HYPOTHESIS A1R antagonizes vasodilatory effects of A2a/bR on coronary circulation. The left main coronary artery of Ossabaw miniature swine was accessed with a guiding catheter allowing intracoronary (IC) infusions. Following placement of a flow‐wire into the left anterior descending coronary artery the responses to IC bolus infusions of 0.167, 0.333, 1, and 3 μg/kg adenosine were obtained. Steady‐state infusion of other adenosine receptor agents utilized a small catheter fed over the flow‐wire. Baseline flow was increased by the A2a/bR agonist CV1808 in a dose‐dependent manner, but not changed by other AR subtype‐specific agents. The A2a/bR antagonist DMPX and the A1R‐selective agonist CCPA decreased adenosine‐mediated vasodilation. CONCLUSIONS A1R negatively regulates A2a/bR‐mediated adenosine vasodilation and adenosine is not involved in regulation of basal flow in the coronary circulation of healthy Ossabaw miniature swine.