Defibrotide, an antithrombotic substance that preserves postsynaptic α- and β-adrenergic function in post acute infarcted rabbit hearts

Ferruccio Berti, Giuseppe Rossoni, Riccardo Niada, Giancarlo Folco, Claudio Omini, Claudio Tondo

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Abstract

Defibrotide, a simple strand polydeoxyribonucleotide of mammalian origin with a molecular weight of 20,000 daltons, given intravenously to the rabbit before and after production of left ventricular infarction, prevents the alteration of the contractile response to postsynaptic adrenergic stimulation tested in isolated perfused heart preparations 3 days after coronary artery occlusion. According to the dose-response curves for isoproterenol and tyramine, left ventricular dP/dtmax was significantly depressed in infarcted hearts, whereas the dose-response curve for the inotropic effect of phenylephrine was markedly enhanced. These alterations were prevented by pretreatment of the rabbits with defibrotide (32 mg/kg/h i.v. for 6 h). In fact the potency ratios, calculated from the dose-response curves related to dP/dtmax of isoproterenol, tyramine, and phenylephrine in infarcted and control hearts excised from defibrotide treated and shamoperated rabbits, are nearly 1. The observed alterations in myocardial contractility in infarcted hearts seem to be specific for postsynaptic α and β-adrenoceptors since the dose-response curve of left ventricular dP/dtmax for histamine is not different from control. The results obtained with defibrotide reflect the ability of this substance to protect the myocardial tissue from ischemic damage: this is also supported by the capacity of defibrotide (8 mg/kg/h i.v. for 6.5 h) to prevent the reduction of CPK-activity in the infarcted ventricle. Finally, we suggest that the observed beneficial effect of defibrotide in rabbit heart may also be explained by the antithrombotic effect of this substance, which is based on its profibrinolytic activity and PGI2-release.

Original languageEnglish
Pages (from-to)235-240
Number of pages6
JournalJournal of Cardiovascular Pharmacology
Volume8
Issue number2
Publication statusPublished - 1986

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Keywords

  • Beta- and alpha-adrenoceptors
  • CPK-Activity
  • Defibrotide
  • Myocardial infarction

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Pharmacology

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