The function and role of the heart and the contribution of cardiac β- 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 β-adrenoceptor activity, number, and affinity. The techniques were the pithed rat preparation, the isolated working heart preparation, and a competitive radioligand binding assay for β-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 β-adrenoceptor agonists, isoproterenol and dobutamine, was unaffected by bile duct ligation. The affinity and number of cardiac β-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 β- adrenoceptor agonists, a normal unchanged affinity and number of cardiac β- adrenoceptors.
|American Journal of Physiology - Gastrointestinal and Liver Physiology
|Published - 1993
- cardiac contractility
- β-adrenoceptor responsiveness