REEVALUATION OF SYRIAN-HAMSTER BIO14.6 AS A MODEL ANIMAL FOR CONGESTIVE-HEART-FAILURE AND CATECHOLAMINE TURNOVER

In order to evaluate the Syrian hamster, Bio14.6, as an animal model o f congestive heart failure (CHF), the response to digitalis in its iso lated cardiac muscle has been studied. Furthermore, plasma norepinephr ine (NE) concentration was determined as well as myocardial NE concent ration. The heart weight-to-body weight ratios were increased signific antly by 19.8 and 23.8% in Stage B (20 weeks old) and Stage C (30 week s old), respectively, compared with those of age-matched control hamst ers, F1B. The pressure rate products, considered by some to be an inde x of cardiac work, decreased significantly in Stage B. The isolated my ocardial preparation of myopathic hamsters demonstrated significant re duction in the response to ouabain at Stage B (20 weeks old). Tile res ponse to NE was also inhibited in the isolated myopathic aorta. Plasma NE concentration was higher than that of control hamsters throughout of all stages. The plasma dopamine-beta-hydroxylase (DBH) activity of myopathic hamsters tended to increase with age. Myocardial tissue grad ually became fibrotic with age, although the ventricular protein conte nts were not affected by the presence of cardiomyopathy. Tile NE conte nt, whether corrected for mg protein or not, tended to decrease with a ge and revealed lower values than in those of F1B. At Stage C, NE cont ent of Bio14.6 was significantly reduced compared with that of FIB. Le ft ventricle dopamine (DA) concentration of Bio14.6 maintained an almo st similar level throughout all stages. The DA/NE ratio, which is a ma rker of DBH activity, tended to increase after Stage B. The cardiac ty rosine hydroxylase (TH) activity of Bio14.6 was lower than that of con trol hamsters. These results confirmed the data obtained from patients with congestive heart failure, of increased plasma NE accompanied by depletion of myocardial NE content and reduction of cardiac TH activit y. Bio14.6 was recognized as an animal model of CHF both in its respon se to digitalis and NE turnover.