title: Dobutamine effects on systole and diastole in rats with myocardial infarction.
abstract: In this article, the authors attempt to determine the effect of catecholamine stimulation on the systolic and diastolic properties of the left ventricle (LV) in rats with chronic infarction. Male Sprague-Dawley rats underwent coronary artery ligation at 8-10 weeks of age. Baseline hemodynamics were measured 1-2 months after infarction. Dobutamine was administered in bolus injections of increasing concentrations, and peak hemodynamic response after each dose was recorded. Rats were divided into three groups: controls (n = 14), rats with infarct size less than 30% of LV (n = 13), and rats with infarct size at least 30% of LV (n = 9). Baseline hemodynamics were similar among the three groups. There was no significant difference in the maximal response of LV systolic pressure and heart rate between the three groups. Left ventricle +dP/dt increased with dobutamine in all three groups, but rats with infarct size of at least 30% had a significantly smaller increase above baseline as compared with control rats. In contrast, LV -dP/dt increased to a similar degree in all three experimental groups with dobutamine. Although hemodynamics can be affected by loading conditions in the intact animal, the magnitude of the change in +dP/dt with unaltered -dP/dt suggests that there is an impaired inotropic but not lusitropic response to catecholamine stimulation in rats with large chronic myocardial infarcts. The findings imply a differential effect of beta-agonist stimulation on systolic and diastolic properties of the heart.
authors: Cardiology Research Laboratory, University of Rochester Medical Center, New York.
authors: C J
authors: CJ
authors: Cove
authors: S C
authors: SC
authors: Widman
authors: C S
authors: CS
authors: Liang
authors: E A
authors: EA
authors: Schenk
authors: W B
authors: WB
authors: Hood
mesh_terms: D000818:Animals; D003971:Diastole / Q000187:drug effects*; D004195:Disease Models, Animal; D004280:Dobutamine / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D009203:Myocardial Infarction / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013599:Systole / Q000187:drug effects*; D016277:Ventricular Function, Left / Q000187:drug effects*
chemical_list: D004280:Dobutamine