Effect of propranolol on early postischemia arrhythmias and noradrenaline and potassium release of ischemic myocardium in anesthetized pigs.
In anesthetized open-chest pigs, DL- or D-propranolol (1 mg/kg i.v.) was administered 15 min prior to ligation of the left anterior descending coronary artery (LAD) about halfway from its origin. Sequential myocardial tissue samples were obtained before and after LAD occlusion. The samples were analyzed histofluorimetrically to determine the density of catecholamine containing neurons (quantified morphometrically), and radioenzymatically for total tissue noradrenaline content. The extracellular K+ concentration was measured using K+-sensitive polyvinyl chloride (PVC)-membrane electrodes on the surface of the ischemic myocardium. Under control conditions, ventricular arrhythmias (VA) occurred in a typical 1a and 1b phase. Pretreatment with propranolol diminished the number of VA generated in the 1b phase but not those in the 1a phase; however, these differences were statistically not significant. Neither pretreatment with DL- nor D-propranolol influenced the time course or probability of development of ventricular fibrillation (VF). Coronary artery occlusion led to a significant reduction in noradrenaline concentration of the ischemic myocardium in control animals (from an initial concentration of 526 +/- 65 ng/g w/w to 368 +/- 75 ng/g w/w) within the first 5 min of ischemia, whereas noradrenaline concentration remained nearly unchanged in drug-treated animals (from 838 +/- 86 to 811 +/- 61 ng/g w/w in the DL group and from 701 +/- 36 to 709 +/- 31 ng/g w/w in animals that received D-propranolol.(ABSTRACT TRUNCATED AT 250 WORDS)
Knopf
H
H
Department of Applied Physiology, University of Cologne, F.R.G.
McDonald
F M
FM
Bischoff
A
A
Hirche
H
H
Addicks
K
K
D000758:Anesthesia; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000188:drug therapy* / Q000209:etiology / Q000401:mortality; D001794:Blood Pressure / Q000187:drug effects; D002395:Catecholamines / Q000378:metabolism; D003327:Coronary Disease / Q000150:complications*; D003331:Coronary Vessels / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D009206:Myocardium / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D011433:Propranolol / Q000627:therapeutic use*; D013552:Swine
D002395:Catecholamines; D011433:Propranolol; D011188:Potassium; D009638:Norepinephrine