Effects of anesthesia and K+ ATP channel blockade on interstitial adenosine accumulation in ischemic rabbit myocardium

• Published in: Basic research in cardiology 1995-09, Vol.90 (5), p.410-417
• Main Authors: COHEN, M. V, SNELL, K. S, TSUCHIDA, A, VAN WYLEN, D. G. L, DOWNEY, J. M
• Format: Article
• Language: English
• Subjects: Adenosine - metabolism; Adenosine Triphosphate - antagonists & inhibitors; Anesthetics - pharmacology; Animals; Antianginal agents. Coronary vasodilator agents; Biological and medical sciences; Cardiovascular system; Chromatography, High Pressure Liquid; Female; Glyburide - pharmacology; Hemodynamics - drug effects; Hypoglycemic Agents - pharmacology; Male; Medical sciences; Myocardial Infarction - etiology; Myocardial Infarction - metabolism; Myocardial Infarction - physiopathology; Myocardial Ischemia - complications; Myocardial Ischemia - metabolism; Myocardial Ischemia - physiopathology; Myocardial Reperfusion; Pharmacology. Drug treatments; Potassium Channel Blockers; Purines - metabolism; Rabbits; Time Factors
• ISSN: 0300-8428; 1435-1803
• DOI: 10.1007/BF00788503

Glibenclamide, a K+ ATP channel antagonist, blocks the anti-infarct effect of ischemic preconditioning in rabbits, but only when the latter are anesthetized with ketamine-xylazine. Furthermore, the protection triggered by pinacidil, a K+ ATP channel opener, can be aborted by treatment with the adenosine antagonist 8-(P-sulfophenyl)theophylline. This study tests whether either the anesthetic regimen or glibenclamide affects infarct size by modulating interstitial adenosine levels. Interstitial adenosine and total purine concentrations were assessed in open-chest rabbits by the microdialysis technique. Dialysis fibers were inserted into myocardium served by a coronary artery branch surrounded by a snare. All animals sustained a 30-min coronary occlusion and then 120-min reperfusion. Rabbits were anesthetized with either sodium pentobarbital or a ketamine-xylazine mixture. Half of the latter animals also received glibenclamide. The control levels of adenosine in the dialysate were comparable in the three groups, as were those of total purines, and the infusion of glibenclamide caused no change. Ischemia led to 10- to 20-fold increases in interstitial adenosine and 10- to 40-fold rises in total purine concentrations. These increases were equivalent in all groups. Further-more, infarct size as a percentage of the myocardium at risk was also comparable in the three groups. Neither the anesthetic agent nor glibenclamide appears to modulate interstitial adenosine release from ischemic tissue.