Ventricular overdrive pacing-induced preconditioning and no-flow ischemia-induced preconditioning in isolated working rat hearts.
To examine preconditioning induced by short periods of ventricular overdrive pacing (VOP) as compared with that induced by no-flow ischemia, we subjected isolated working rat heart to 10-min coronary artery occlusion (test ischemia) followed by 3-min reperfusion after three intermittent periods of VOP (10 Hz) or 5-min no-flow ischemia, respectively. In the nonpreconditioned group, coronary occlusion decreased aortic flow (AF) from 46.6 +/- 2.4 to 13.7 +/- 1.7 ml/min and increased left ventricular end-diastolic pressure (LVEDP) from 0.53 +/- 0.05 to 2.02 +/- 0.07 kPa. Preconditioning by VOP or no-flow ischemia significantly increased AF to 25.1 +/- 2.3 ml/min (p < 0.001) and to 27.3 +/- 1.4 ml/min (p < 0.001) and decreased LVEDP to 1.38 +/- 0.1 kPa (p < 0.001) and to 1.65 +/- 0.05 kPa (p < 0.05), respectively, after test ischemia. Glibenclamide 10(-7) M which blocked the anti-ischemic effect of the ATP-sensitive K(+)-channel (KATP) opener cromakalim, inhibited VOP-induced protection (AF 20.3 +/- 2.3 ml/min; LVEDP 1.82 +/- 0.15 kPa), but did not affect no-flow ischemia-induced preconditioning [AF 26.6 +/- 2.4 ml/min (p < 0.001), LVEDP 1.60 +/- 0.07 kPa (p < 0.01)]. VOP and no-flow ischemia precondition heart, however their cardioprotective mechanisms may be different in terms of KATP activation in rats.
Ferdinandy
P
P
Department of Physiology, Albert Szent-Györgyi University Medical School, Szeged, Hungary.
Szilvássy
Z
Z
Koltai
M
M
Dux
L
L
D000818:Animals; D001578:Benzopyrans / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002304:Cardiac Pacing, Artificial; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology; D019806:Cromakalim; D004195:Disease Models, Animal; D005905:Glyburide / Q000494:pharmacology; D006321:Heart / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D017202:Myocardial Ischemia / Q000473:pathology* / Q000503:physiopathology / Q000517:prevention & control; D015425:Myocardial Reperfusion; D015428:Myocardial Reperfusion Injury / Q000473:pathology / Q000517:prevention & control; D015221:Potassium Channels / Q000187:drug effects*; D011758:Pyrroles / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014665:Vasodilator Agents / Q000494:pharmacology
D001578:Benzopyrans; D015221:Potassium Channels; D011758:Pyrroles; D014665:Vasodilator Agents; D019806:Cromakalim; D005905:Glyburide