| Propranolol: Pharmacology
The levorotatory isomer of propranolol binds reversibly with ß1- and ß2-adrenoreceptors; both receptors have membrane stabilizing activity. Propranolol leads to a reduction of the heart rate and of the cardiac output; initially the hypotensive effect is delayed because of peripheral vasoconstriction. The AV nodal conduction time and the AV refractoriness are prolonged. Blood flow decreases in most vascular territories. Propranolol also increases plasma renin activity and suppresses lipolysis. In the plasma the triglycerides increase, whereas the HDL cholesterol decreases slightly. The bond between propranolol and ß2-receptors causes an increase of the airway resistance and the inhibition of glycogenolysis and gluconeogenesis.