Erythropoietin changes contractility, cAMP, and nitrite levels of isolated rat hearts.
There is enough evidence that erythropoietin (EPO) may be involved in cardiovascular function. Therefore we have investigated the possible effects of EPO on left ventricular developed pressure, +dP/dt(max), heart rate, tissue cAMP, and nitrite levels. Isolated rat hearts were perfused under constant flow (10 ml/min) conditions with modified Krebs-Henseleit solution and recombinant human erythropoietin at doses of 100, 200, 500, and 1,000 IU/kg was administered as bolus injections. EPO at 100 IU/kg decreased, but higher doses (500 and 1,000 IU/kg) raised the developed pressure and +dP/dt(max). However, it did not affect heart rate or coronary perfusion pressure when all the respective doses were applied. EPO at 100 IU/kg increased nitrite, and at 1,000 IU/kg it raised cAMP. Our results suggest that EPO may produce dose-dependently negative and positive inotropic effects on myocardial contractility in isolated rat hearts. NO and cAMP may be involved in negative and positive inotropic effects of EPO, respectively.
Kaygisiz
Ziya
Z
Department of Physiology, Medical Faculty, Eskiehir Osmangazi University, 26480 Eskişehir, Turkey. ziyak@ogu.edu.tr
Erkasap
Nilufer
N
Yazihan
Nuray
N
Sayar
Kemal
K
Ataoglu
Haluk
H
Uyar
Ruhi
R
Ikizler
Murat
M
D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004921:Erythropoietin / Q000502:physiology*; D005260:Female; D006321:Heart / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology*; D009206:Myocardium / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013318:Stroke Volume / Q000502:physiology; D013997:Time Factors
D009573:Nitrites; D004921:Erythropoietin; D000242:Cyclic AMP