标题：Cardiomyopathic Hamster Hearts : Long-Term Effects of Drugs on Catecholamine Contents and Binding Characteristics of α1- and β1-Adrenergic Receptors
摘要：Changes were examined in myocardial catecholamine content and α1- and β1-adrenoceptors during the development of cardiomyopathy in Syrian hamsters (Bio 14.6) and age-matched healty controls. In addition, the effects of bunazosin, atenolol, xamoterol, ketanserin, and verapamil on the catecholamine content and [3H]prazosin, [3H]CGP12177 bindings to α1- and β1-adrenergic receptors of myocardium were compared with those of the controls. (1) Lower norepinephrine and dopamine levels were observed in 35-week-old cardiomyopathic hamster hearts than in the controls. There was, however, a tendency for a slight decrease of α1- and β1-adrenoceptors in cardiomyopathic hamsters. (2) Administration of bunazosin induced lower dopamine values in 18-week-old cardiomyopathic hamsters. (3) Xamoterol induced a higher Kd value for β1-adrenoceptors and lower dopamine content than for those with cardiomyopathy. Ketanserin also induced a higher Bmax value than for cardiomyopathy. Thus, drug treatments clearly change catecholamine content and binding characteristics of the adrenoceptors which play an important role in the development of cardiac hypertrophy and heart failure.
