Abstract
Drugs are subject to type-casting. Once we become impressed with their stellar performance of an important pharmacologic function, we tend to attribute all their effects to this mechanism. Propranolol is an outstanding example of this conceptual short circuit.The existence of two types of adrenergic receptors, termed alpha and beta, was suggested by Ahlquist 27 years ago.1 It has provided an excellent basis for classifying the actions of the many sympathomimetic amines on their multiple effector organs and for categorizing compounds that selectively inhibit certain responses to these amines and to adrenergic nerve activity. Sympathomimetic amines vary only quantitatively in . . .