Status of β1-Adrenoceptor Signal Transduction System in Cardiac Hypertrophy and Heart Failure

Although β1-adrenoceptor (β1-AR) signal transduction, which maintains cardiac function, is downregulated in failing hearts, the mechanisms for such a defect heart failure are not fully understood. Since hypertrophy invariably associated with failure, it possible that loss of β1-AR occurs due to hypertrophic process. In this regard, we have reviewed information from rat model adaptive and maladaptive at 4 24 weeks after inducing pressure overload as well volume overload, respectively. Varying degrees alterations density isoproterenol-induced increases intracellular Ca2+-concentration cardiomyocytes adenylyl cyclase activity crude membranes been reported under these conditions. Adaptive or showed unaltered augmented activities different components signaling. On other hand, revealed depressions transduction pathway. These observations provide evidence system either upregulated failure. Furthermore, presented article supports concept downregulation process per se. It suggested complex mechanism involving autonomic imbalance may be critical importance determining differential non-failing hearts.