ADENOSINE-A(1) RECEPTORS, K(ATP) CHANNELS, AND ISCHEMIC PRECONDITIONING IN DOGS

Citation
Ja. Auchampach et Gj. Gross, ADENOSINE-A(1) RECEPTORS, K(ATP) CHANNELS, AND ISCHEMIC PRECONDITIONING IN DOGS, The American journal of physiology, 264(5), 1993, pp. 1327-1336
Citations number
33
Categorie Soggetti
Physiology
ISSN journal
00029513
Volume
264
Issue
5
Year of publication
1993
Part
2
Pages
1327 - 1336
Database
ISI
SICI code
0002-9513(1993)264:5<1327:ARKCAI>2.0.ZU;2-Z
Abstract
The objective of the present study was to characterize the role of ade nosine in myocardial ischemic preconditioning in the canine heart. Pre conditioning with 5 min of ischemia resulted in a marked reduction in infarct size after 60 min of left circumflex coronary artery occlusion and 5 h of reperfusion in barbital-anesthetized dogs compared with do gs that were not preconditioned (4.8 +/- 1.9 vs. 27.9 +/- 4.5%; P < 0. 05). Pretreatment with either the nonselective adenosine receptor anta gonist PD 115199 or the selective adenosine A1 receptor antagonist 8-c yclopentyl-1,3-dipropylxanthine blocked this protective effect, althou gh in the absence of preconditioning neither of the antagonists affect ed infarct size. Intracoronary infusion of two different doses of aden osine or dipyridamole over a 5-min period before a prolonged 60-min oc clusion period did not mimic preconditioning; however, intracoronary i nfusion of a combination of adenosine and dipyridamole produced a sign ificant reduction in infarct size (13.6 +/- 4.1%), which was abolished by pretreatment with the ATP-dependent potassium (K(ATP)) channel ant agonist glibenclamide. These results suggest that activation of adenos ine A1 receptors produces myocardial preconditioning in the canine hea rt by opening K(ATP) channels.