Beta blockers are among the most widely used drugs for treating heart failure. It has long been thought that these drugs act on proteins, known as adrenergic receptors, that solely reside on cell surfaces. A recent study by scientists at CVRI and the University of Michigan has discovered a previously unknown role for adrenergic receptors within cells. When beta blockers were developed, there were no considerations for their abilities to access internal adrenergic receptors. This new knowledge can potentially lead to the development of drugs that are more effective in the treatment of cardiovascular disease.