Myocardial Infarction and Natural Defense Mechanisms: The Role of Norepinephrine Reuptake
Purpose: to study effect of norepinephrine reuptake blockade in reperfusion period on size of infarct caused by local ischemia with and without ischemic pre- and postconditioning. Material and methods. Wistar rats (n = 46) were randomly divided into 6 groups. Group (gr) I (n = 7) - 30 min occlusion of left coronary artery followed by 120 reperfusion; gr II (n = 2) as in gr I +desipramine (0.8 mg/kg intravenously [i.v.]) at the start of reperfusion; gr III (n = 6) - ischemic preconditioning before coronary artery occlusion; gr IV (n = 7) -as in group 3 + desipramine (0.8 mg/kg i.v.) at the start of reperfusion; gr V (n = 9) ischemic postconditioning after occlusion; gr VI (n = 10) -as in group 5 + desipramine (0.8 mg/kg i.v.) at the start of reperfusion. One ml of Ringer's solution was injected i.v. at the start of reperfusion to rats of gr I, III, and V. Results. Dimensions of infarct zone (in % of zone at risk) were: gr I 32.0±3.1 of, gr II 46.1 ±3.4% (р=0.006); gr III 15.3±3.1% (р = 0.008 vs gr I), gr IV - 44.7±4.7 (р=0.0027 vs gr III), gr V - 22.2±2.6 (р = 0.028 vs gr I), gr VI - 50.3±3.1 (р = 0.018 и p>0.05 vs gr V and II, respectively). Conclusion. Blockade of norepinephrine reuptake in early reperfusion period led to increase of myocardial injury, and interfered with protective action of ischemic pre- and postconditioning.