Role of the endocardium in the inotropic action of UD-CG-212 CL.
UD-CG-212 CL is a metabolite of pimobendan (UD-CG-115 BS), a non-glycosidic, non-adrenergic positive inotropic agent. In the present study we investigated the effect of UD-CG-212 CL on cat papillary muscles in the presence or absence of an intact endocardial endothelium. The endocardium was damaged by a very short detergent treatment. We demonstrated that, in muscles with an intact endocardial endothelium, UD-CG-212 CL induced a moderate, but significant inotropic effect resembling the changes induced by adrenoceptor agonists. Addition of an alpha- and or beta-blocker reduced this positive inotropic effect. The effect induced by UD-CG-212 CL, was completely abolished after the endocardial endothelium was damaged. We conclude that the endocardium played a modulatory role in the action of UD-CG-212 CL through the release of various factors with inotropic activity.
Department of Physiology, University of Antwerp, Belgium.
A L
AL
Meulemans
D L
DL
Brutsaert
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002316:Cardiotonic Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D002415:Cats; D004699:Endocardium / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects*; D010210:Papillary Muscles / Q000187:drug effects; D011724:Pyridazines / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D002316:Cardiotonic Agents; D011724:Pyridazines; C047936:UD CG 212 Cl