Nadolol

Although nadolol is described as a non selective beta blocker, it does not interact with beta 3 adrenal receptors. Antagonism of beta-1 and beta-2 adrenoceptors in the heart inhibits cyclic AMP and its signalling pathway, decreasing the strength and speed of contractions as well as the speed of relaxation and conduction. Antagonism of beta-2 adrenoceptors in the smooth muscle cells of the vasculature inhibits their relaxation, leading to an increase in peripheral vascular resistance and reducing the risk of severe hypotension. The increase in peripheral vascular resistance may contribute to the decrease in insulin sensitivity associated with nadolol use. Antagonism of beta-1 adrenoceptors in the juxtaglomerular apparatus of the kidney inhibits the release of renin, and therefore angiotensin II mediated vasoconstriction, aldosterone mediated water retention, and the release of epinephrine. Antagonism of beta-2 adrenoceptors in the liver and skeletal muscle inhibits glycogenolysis, in the lungs prevents bronchodilation, and in the pancrease inhibits insulin release.