title: Opioid peptides in experimental myocardial infarction. I. The effect of naloxone.
abstract: The effect of intravenous administration of the opioid antagonist naloxone in rats with acute left coronary artery ligation was studied. The results demonstrated that naloxone in a dose 2 mg/kg b. w. affords its protection on infarcted animals by two mechanisms: Reduces by 22% the incidence of early arrhythmias that occur within 15-20 minutes of acute myocardial ischaemia, and are responsible for the early (up to the 30th minutes) postligation death; Reverses the hypotension that results from the development of cardiogenic shock after 30 minutes myocardial infarction. The total mortality after naloxone treatment was significantly reduced by 22%. Naloxone does not influence significantly the size of the infarcted area but the incidence of left ventricle wall perforations was decreased by 38%. Both effects of naloxone are attributed to the antagonism of opioid receptors either directly on the myocardium or through blocking the central action of beta-endorphin. A direct effect of naloxone on the cardiac muscle action potential cannot be excluded.
mesh_terms: D000136:Acid-Base Equilibrium; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology; D003331:Coronary Vessels; D008026:Ligation; D008297:Male; D009203:Myocardial Infarction / Q000503:physiopathology*; D009270:Naloxone / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D009270:Naloxone