title: Protective roles of adenosine A1, A2A, and A3 receptors in skeletal muscle ischemia and reperfusion injury.
abstract: Although adenosine exerts cardio-and vasculoprotective effects, the roles and signaling mechanisms of different adenosine receptors in mediating skeletal muscle protection are not well understood. We used a mouse hindlimb ischemia-reperfusion model to delineate the function of three adenosine receptor subtypes. Adenosine A(3) receptor-selective agonist 2-chloro-N(6)-(3-iodobenzyl)adenosine-5'-N-methyluronamide (Cl-IBMECA; 0.07 mg/kg ip) reduced skeletal muscle injury with a significant decrease in both Evans blue dye staining (5.4 +/- 2.6%, n = 8 mice vs. vehicle-treated 28 +/- 6%, n = 7 mice, P < 0.05) and serum creatine kinase level (1,840 +/- 910 U/l, n = 13 vs. vehicle-treated 12,600 +/- 3,300 U/l, n = 14, P < 0.05), an effect that was selectively blocked by an A(3) receptor antagonist 3-ethyl-5-benzyl-2-methyl-6-phenyl-4-phenylethynyl-1,4-(+/-)-dihydropyridine-3,5-dicarboxylate (MRS-1191; 0.05 mg/kg). The adenosine A(1) receptor agonist 2-chloro-N(6)-cyclopentyladenosine (CCPA; 0.05 mg/kg) also exerted a cytoprotective effect, which was selectively blocked by the A(1) antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; 0.2 mg/kg). The adenosine A(2A) receptor agonist 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine (CGS-21680; 0.07 mg/kg)-induced decrease in skeletal muscle injury was selectively blocked by the A(2A) antagonist 2-(2-furanyl)-7-[3-(4-methoxyphenyl)propyl]-7H-pyrazolo[4,3-e] [1,2,4]triazolo[1,5-C]pyrimidin-5-amine (SCH-442416; 0.017 mg/kg). The protection induced by the A(3) receptor was abrogated in phospholipase C-beta2/beta3 null mice, but the protection mediated by the A(1) or A(2A) receptor remained unaffected in these animals. The adenosine A(3) receptor is a novel cytoprotective receptor that signals selectively via phospholipase C-beta and represents a new target for ameliorating skeletal muscle injury.
authors.affiliation: Pat and Jim Calhoun Cardiology Center, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA.
authors.forename: Jingang
authors.initials: J
authors.lastname: Zheng
authors.forename: Rubio
authors.initials: R
authors.lastname: Wang
authors.forename: Edward
authors.initials: E
authors.lastname: Zambraski
authors.forename: Dan
authors.initials: D
authors.lastname: Wu
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Jacobson
authors.forename: Bruce T
authors.initials: BT
authors.lastname: Liang
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D004095:Dihydropyridines / Q000494:pharmacology; D004195:Disease Models, Animal; D006614:Hindlimb; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018482:Muscle, Skeletal / Q000098:blood supply / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D010627:Phenethylamines / Q000494:pharmacology; D054799:Phospholipase C beta / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D011720:Pyrazoles / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D043682:Receptor, Adenosine A1 / Q000187:drug effects / Q000378:metabolism*; D043705:Receptor, Adenosine A2A / Q000378:metabolism*; D043684:Receptor, Adenosine A3 / Q000187:drug effects / Q000378:metabolism*; D015427:Reperfusion Injury / Q000378:metabolism* / Q000517:prevention & control; D015398:Signal Transduction / Q000187:drug effects; D014970:Xanthines / Q000494:pharmacology
chemical_list: D004095:Dihydropyridines; C107728:MRS 1191; D010627:Phenethylamines; D011720:Pyrazoles; D011743:Pyrimidines; D043682:Receptor, Adenosine A1; D043705:Receptor, Adenosine A2A; D043684:Receptor, Adenosine A3; D014970:Xanthines; C061282:2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine; C058394:2-chloro-N(6)cyclopentyladenosine; C051360:1,3-dipropyl-8-cyclopentylxanthine; D054799:Phospholipase C beta; C518037:Plcb2 protein, mouse; C518040:Plcb3 protein, mouse; D000241:Adenosine; C090034:2-chloro-N(6)-(3-iodobenzyl)adenosine-5'-N-methyluronamide; C416650:SCH 442416