THE HEMODYNAMICS OF ISOPROTERENOL-INDUCED CARDIAC-FAILURE IN THE RAT

  • 1 January 1981
    • journal article
    • research article
    • Vol. 8  (2) , 151-163
Abstract
In virgin, male Sprague-Dawley rats, s.c. injections of 2.5 mg/kg or 250 mg/kg isoproterenol increased heart rate and aortic dF/dt [1st derivative of pressure] and decreased total peripheral resistance. The net systemic response was an arterial hypotension. The larger dose of isoproterenol initially produced a greater hypotension; reflex compensatory responses followed. Cardiac failure occurred by 24 h post-isoproterenol. The extent of cardiac failure was isoproterenol dose dependent. By gross inspection of the epicardial surface of the hearts of the isoproterenol-treated rats, anatomical injury appeared to be isoproterenol dose dependent. Isoproterenol-induced myocardial damage is probably due to a relative myocardial hypoxia produced by arterial hypotension and myocardial hyperactivity. Reflex responses to arterial hypotension occur and may be detrimental. Cardiac failure is produced by massive quantities of isoproterenol and the degree of cardiac failure is dose dependent.