The cardiac contractile function and hemodynamic control in rats after chronic adriamycin treatment.
Cardiac contractile function and hemodynamic parameters of control and adriamycin-treated (2 mg/kg once a week for 10 weeks) rats were studied both in the anesthetized (hexenal, 20 mg/kg) and conscious state. Radiolabelled microspheres (diameter, 15 microns) were used to measure systemic and regional hemodynamics. No significant differences between the control and adriamycin-treated groups in cardiac contractile function, total peripheral resistance, and regional blood flow (except muscles) was found in anesthetized animals. In the conscious state, a significantly higher (+70%) total peripheral resistance combined with lower blood flow in the skin and spleen was observed in adriamycin-treated rats. The response of the heart rate to changes in the arterial pressure induced by nitroglycerin and phenylephrine injection was greatly diminished after adriamycin treatment. Isoprenaline (0.64 micrograms.kg-1.min-1) increased left ventricular contractile indices approximately twofold and heart rate by 30% in the control group, while in adriamycin-treated rats only minor changes in these parameters were observed. However, cardiac output rose by 36% and total peripheral resistance fell by 36% in these animals. Results show that prolonged adriamycin treatment leads to decreased inotropic response to beta-adrenoceptor stimulation and reduced baroreflex control. These changes occur in the stage preceding congestive heart failure.
Gorodetskaya
E A
EA
Cardiology Research Center of the U.S.S.R., Academy of Medical Sciences, Moscow.
Dugin
S F
SF
Golikov
M A
MA
Kapelko
V I
VI
Medvedev
O S
OS
D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D004317:Doxorubicin / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007262:Infusions, Intravenous; D007545:Isoproterenol / Q000008:administration & dosage / Q000494:pharmacology; D008863:Microspheres; D009200:Myocardial Contraction / Q000187:drug effects*; D011311:Pressoreceptors / Q000187:drug effects; D051381:Rats; D012018:Reflex / Q000187:drug effects; D012039:Regional Blood Flow / Q000187:drug effects
D004317:Doxorubicin; D007545:Isoproterenol