title: Erythropoietin changes contractility, cAMP, and nitrite levels of isolated rat hearts.
abstract: 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.
authors.affiliation: Department of Physiology, Medical Faculty, Eskiehir Osmangazi University, 26480 Eskişehir, Turkey. ziyak@ogu.edu.tr
authors.forename: Ziya
authors.initials: Z
authors.lastname: Kaygisiz
authors.forename: Nilufer
authors.initials: N
authors.lastname: Erkasap
authors.forename: Nuray
authors.initials: N
authors.lastname: Yazihan
authors.forename: Kemal
authors.initials: K
authors.lastname: Sayar
authors.forename: Haluk
authors.initials: H
authors.lastname: Ataoglu
authors.forename: Ruhi
authors.initials: R
authors.lastname: Uyar
authors.forename: Murat
authors.initials: M
authors.lastname: Ikizler
mesh_terms: 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
chemical_list: D009573:Nitrites; D004921:Erythropoietin; D000242:Cyclic AMP