Endothelin-1 exacerbates diastolic stunning in conscious dogs.
The purpose of this study was to examine the effects of endothelin-1 (ET-1) on "diastolic stunning" in the postischemic myocardium. In 14 conscious dogs receiving either placebo (n = 7) or ET-1 (2.5 ng.kg-1.min-1, n = 7), left ventricular (LV) hemodynamics and regional wall motion (systolic segmental shortening by sonomicrometry and the ischemic-nonischemic regional asynchrony during isovolumic relaxation) were assessed at baseline, during 10 min of left anterior descending coronary artery occlusion (CAO) and at 60 min after reflow (R-60). During CAO, the ischemic segment shortening was severely depressed and both regional asynchrony and LV relaxation time constant were significantly increased in the placebo and ET-1 groups. At R-60, this LV diastolic dysfunction recovered to baseline conditions in the placebo group but was still present in the ET-1 group. Because coronary and myocardial blood flow returned to the baseline level at R-60 in both groups, the deleterious effects of ET-1 on diastolic stunning are probably mediated by its direct action on the myocardium.
Hayashida
W
W
Department of Physiology and Pharmacology, School of Medicine, University of Louvain, Brussels, Belgium.
Donckier
J
J
van Mechelen
H
H
Stoleru
L
L
Pouleur
H
H
D000818:Animals; D003243:Consciousness; D003326:Coronary Circulation / Q000187:drug effects*; D003971:Diastole / Q000187:drug effects / Q000502:physiology*; D004285:Dogs; D004562:Electrocardiography / Q000187:drug effects; D016232:Endothelins / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D004837:Epinephrine / Q000097:blood; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007262:Infusions, Intravenous; D009200:Myocardial Contraction / Q000187:drug effects; D017202:Myocardial Ischemia / Q000097:blood / Q000503:physiopathology*; D017682:Myocardial Stunning; D009638:Norepinephrine / Q000097:blood; D012039:Regional Blood Flow / Q000187:drug effects; D013599:Systole / Q000187:drug effects; D016277:Ventricular Function, Left / Q000187:drug effects
D016232:Endothelins; D009638:Norepinephrine; D004837:Epinephrine