title: Adenosine-enhanced ischemic preconditioning: adenosine receptor involvement during ischemia and reperfusion.
abstract: Adenosine-enhanced ischemic preconditioning (APC) extends the cardioprotection of ischemic preconditioning (IPC) by both significantly decreasing myocardial infarct size and significantly enhancing postischemic functional recovery. In this study, the role of adenosine receptors during ischemia-reperfusion was determined. Rabbit hearts (n = 92) were used for Langendorff perfusion. Control hearts were perfused for 180 min, global ischemia hearts received 30-min ischemia and 120-min reperfusion, and IPC hearts received 5-min ischemia and 5-min reperfusion before ischemia. APC hearts received a bolus injection of adenosine coincident with IPC. Adenosine receptor (A(1), A(2), and A(3)) antagonists were used with APC before ischemia and/or during reperfusion. GR-69019X (A(1)/A(3)) and MRS-1191/MRS-1220 (A(3)) significantly increased infarct size in APC hearts when administered before ischemia and significantly decreased functional recovery when administered during both ischemia and reperfusion (P < 0.05 vs. APC). DPCPX (A(1)) administered either before ischemia and/or during reperfusion had no effect on APC cardioprotection. APC-enhanced infarct size reduction is modulated by adenosine receptors primarily during ischemia, whereas APC-enhanced postischemic functional recovery is modulated by adenosine receptors during both ischemia and reperfusion.
authors.affiliation: Division of Cardiothoracic Surgery, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02115, USA. james_mccully@hms.harvard.edu
authors.forename: J D
authors.initials: JD
authors.lastname: McCully
authors.forename: Y
authors.initials: Y
authors.lastname: Toyoda
authors.forename: M
authors.initials: M
authors.lastname: Uematsu
authors.forename: R D
authors.initials: RD
authors.lastname: Stewart
authors.forename: S
authors.initials: S
authors.lastname: Levitsky
mesh_terms: D000241:Adenosine / Q000494:pharmacology*; D000818:Animals; D004095:Dihydropyridines / Q000494:pharmacology; D066298:In Vitro Techniques; D019157:Ischemic Preconditioning, Myocardial; D009203:Myocardial Infarction / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000378:metabolism*; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D011817:Rabbits; D018047:Receptors, Purinergic P1 / Q000378:metabolism*; D017725:Ventricular Pressure; D014970:Xanthines / Q000494:pharmacology
chemical_list: D004095:Dihydropyridines; C107728:MRS 1191; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D018047:Receptors, Purinergic P1; D014970:Xanthines; C051360:1,3-dipropyl-8-cyclopentylxanthine; D000241:Adenosine