Effects of dopexamine on heart function of isolated hypoxic rabbit heart and in comparison with fenoldopam and procaterol.
OBJECTIVE
To study the effects of dopexamine hydrochloride (Dop) on heart functions and coronary flow (CF) of normal and hypoxic isolated perfusing heart and compare the effects of Dop with those of fenoldopam hydrochloride (Fen) and procaterol hydrochloride (Pro).


METHODS
The isolated rabbit normal and hypoxic hearts were perfused with Krebs-Henseleit (K-H) solution via aorta at 37 +/- 0.5 degree C. The drug were added into the K-H solution.


RESULTS
Dop increased the CF, left ventricular contractile function (+ dp/dtmax etc) and heart rate (HR) in normal heart; Fen increased the heart function more potently, but increased the CF to a lesser degree than Dop did, whereas the effects of Pro was the least. In simple hypoxic group, at 30 min of perfusion, the + dp/dtmax and CF decreased by 66 +/- 4% and 48.1 +/- 1.0%, respectively. Dop remarkably attenuated the decreases in both CF and heart function during hypoxia as it decreased the + dp/dtmax by 32.0 +/- 2.4% and CF by 28 +/- 3%. Fen was less potent than Dop in attenuating the diminution of CF, while Pro was the least effective.


CONCLUSIONS
Dop has a better prospect in the treatment of ischemic heart disease in view of its dual action of increasing CF and inotropism.
Qin
F Z
FZ
Department of Physiology, Shanxi Medical College, Taiyuan, China.
Wang
W Z
WZ
Zhao
R R
RR
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects*; D004298:Dopamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D018491:Dopamine Agonists / Q000494:pharmacology*; D005260:Female; D018818:Fenoldopam / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D000860:Hypoxia / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D017265:Procaterol / Q000494:pharmacology; D011817:Rabbits
D000318:Adrenergic beta-Agonists; D018491:Dopamine Agonists; C046318:dopexamine; D018818:Fenoldopam; D004298:Dopamine; D017265:Procaterol