Affiliation:
1. Centre for Experimental Surgery and Anaesthesiology, University of Leuven, Belgium.
Abstract
To investigate the mechanism underlying postischemic cardiac dysfunction (myocardial stunning), contractility and adenine nucleotide metabolism were studied in three groups of isolated perfused rabbit hearts (control, ischemic, and reperfused), whereas Ca2+ uptake by the sarcoplasmic reticulum (SR) was measured in homogenates obtained from them. The hearts were Langendorff-perfused under constant pressure with Krebs-Henseleit solution at 37 degrees C. Global normothermic ischemia was produced by closing the perfusion line. In the reperfused group, after 15 minutes of ischemia, Krebs-Henseleit solution was perfused for 10 minutes. Developed left ventricular pressure (control, 104 +/- 6.3 mm Hg) and left ventricular dP/dt (2,063 +/- 256.6 mm Hg.sec-1) were significantly decreased in reperfused hearts (left ventricular pressure, 78 +/- 5.9 mm Hg; left ventricular dP/dt, 1,339 +/- 216.3 mm Hg.sec-1). Myocardial ATP content (control, 13.6 +/- 0.98 mumol/g dry wt) decreased during ischemia (4.5 +/- 1.23 mumol/g) but was restored to control level on reperfusion (11.8 +/- 0.68 mumol/g). Maximum velocity of Ca2+ uptake by the SR (Vmax) (control, 49.3 +/- 2.54 nmol.min-1 x mg-1) was significantly depressed by ischemia (36.3 +/- 1.94 nmol.min-1 x mg-1) but was restored to the control value after a 10-minute reperfusion (45.3 +/- 0.79 nmol.min-1 x mg-1). Apparent dissociation constant KCa and the Hill coefficient for Ca2+ uptake were not different between control, ischemia, and reperfusion. To test for the possible role of the SR Ca(2+)-release channel in the effect of ischemia and reperfusion, we measured Ca2+ uptake after incubation of homogenates with 610 microM ryanodine.(ABSTRACT TRUNCATED AT 250 WORDS)
Publisher
Ovid Technologies (Wolters Kluwer Health)
Subject
Cardiology and Cardiovascular Medicine,Physiology
Cited by
83 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献