Cardiac function and responsiveness to beta-adrenoceptor agonists in rats with obstructive jaundice.
The function and role of the heart and the contribution of cardiac beta-adrenoceptors in the pathogenesis of circulatory failure in obstructive jaundice were studied in the 3-day bile duct-ligated (BDL) rat using three different techniques to measure cardiac function and beta-adrenoceptor activity, number, and affinity. The techniques were the pithed rat preparation, the isolated working heart preparation, and a competitive radioligand binding assay for beta-adrenoceptors. The results of these experiments were compared with those obtained in 3-day bile duct-manipulated (sham operated; SO) rats. Impaired indexes of basal cardiac contractility were observed in the BDL pithed rats and isolated working hearts. In these two preparations, responsiveness to norepinephrine and the beta-adrenoceptor agonists, isoproterenol and dobutamine, was unaffected by bile duct ligation. The affinity and number of cardiac beta-adrenoceptors in membranes from the hearts of SO and BDL rats were not significantly different from each other. These experiments have established for the first time that the 3-day BDL rat has a cardiac myopathy associated with intact responsiveness to beta-adrenoceptor agonists, a normal unchanged affinity and number of cardiac beta-adrenoceptors.
Jacob
G
G
Department of Pharmacology, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa.
Nassar
N
N
Hayam
G
G
Ben-Haim
S
S
Edoute
Y
Y
Better
O S
OS
Bomzon
A
A
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D001652:Bile Ducts; D001774:Blood Chemical Analysis; D002779:Cholestasis / Q000503:physiopathology*; D003655:Decerebrate State; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology*; D008026:Ligation; D008102:Liver Circulation; D008297:Male; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011943:Receptors, Adrenergic, beta / Q000378:metabolism
D000318:Adrenergic beta-Agonists; D011943:Receptors, Adrenergic, beta