title: Chronic administration of an endothelin-A receptor antagonist improves exercise capacity in rats with myocardial infarction-induced congestive heart failure.
abstract: The effects of long-term administration of YM598, a selective endothelin-A antagonist, on improving the exercise tolerance of chronic heart failure model rats were examined using a treadmill exercise loading test. Rats were acclimatized to the treadmill apparatus and the coronary artery was ligated to prepare a myocardial infarction-induced congestive heart failure (CHF) model. Starting 10 days postoperatively, when the acute phase of infarction was over, YM598 was administered orally once daily for approximately 25 weeks at a dose of 1 mg/kg. At weeks 20 and 24 the treadmill test was performed. YM598 prolonged running time, which had been shortened as a result of heart failure. The weights, relative to the body weight, of the left and right ventricles and lungs of surviving rats with CHF were significantly greater than those of sham-operated rats, suggesting hypertrophy of the ventricles and congestion of the lungs. Administration of YM598 markedly reduced ventricular hypertrophy and pulmonary congestion. Examination of cardiac function revealed that, in surviving CHF rats, the peak positive first derivative of left ventricular pressure was significantly lower, and left ventricular end-diastolic pressure, right ventricular systolic pressure and central venous pressure were significantly higher in comparison to sham-operated rats. These data demonstrate that, in rats with CHF, the contractile and diastolic capacity of the left ventricle decreased and pulmonary hypertension and systemic congestion occurred. Long-term administration of YM598 improved left ventricular function of CHF rats to the level of sham-operated rats, and reduced the workload placed on the right side of the heart. Histological examination revealed that long-term treatment with YM598 prevented fibrosis of the surviving left ventricular myocardium. In conclusion, long-term administration of YM598 to rats with CHF improved exercise tolerance and inhibited remodeling of cardiac muscles, leading to marked improvement of cardiac function.
authors.affiliation: Cardiovascular Division, Department of Internal Medicine, Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan. t-miyauc@md.tsukuba.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Miyauchi
authors.forename: Akira
authors.initials: A
authors.lastname: Fujimori
authors.forename: Seiji
authors.initials: S
authors.lastname: Maeda
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Iemitsu
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sakai
authors.forename: Hisataka
authors.initials: H
authors.lastname: Shikama
authors.forename: Takumi
authors.initials: T
authors.lastname: Tanabe
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Matsuda
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Goto
authors.forename: Iwao
authors.initials: I
authors.lastname: Yamaguchi
mesh_terms: D000284:Administration, Oral; D000818:Animals; D006332:Cardiomegaly / Q000209:etiology / Q000517:prevention & control; D002317:Cardiovascular Agents / Q000008:administration & dosage / Q000494:pharmacology*; D004195:Disease Models, Animal; D065130:Endothelin A Receptor Antagonists; D017079:Exercise Tolerance / Q000187:drug effects*; D005355:Fibrosis; D006333:Heart Failure / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D006976:Hypertension, Pulmonary / Q000209:etiology / Q000517:prevention & control; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009203:Myocardial Infarction / Q000150:complications* / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology; D005082:Physical Exertion; D011743:Pyrimidines / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013449:Sulfonamides / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors; D016277:Ventricular Function, Left / Q000187:drug effects; D017725:Ventricular Pressure / Q000187:drug effects; D020257:Ventricular Remodeling / Q000187:drug effects
chemical_list: D002317:Cardiovascular Agents; D065130:Endothelin A Receptor Antagonists; C449179:N-(6-methoxy-5-(2-methoxyphenoxy)-2-(pyrimidin-2-yl)pyrimidin-4-yl)-2-phenylethenesulfonamide; D011743:Pyrimidines; D013449:Sulfonamides