Beta-Adrenergic Receptor Blocking Drugs

Abstract
THE concept that effector cells contain excitatory and inhibitory "receptor substances" and that the effects of epinephrine are dependent upon the types of receptor substances present was first suggested by Langley1 more than sixty years ago. This hypothesis received support in 1906, when Dale's2 comprehensive studies on the adrenergic blocking activity of ergot derivatives was published. Although these drugs completely antagonized and even reversed the excitatory actions of epinephrine they had no effect on the inhibitory actions. The only excitatory action of epinephrine that was not inhibited by ordinary doses of ergot was its stimulation of the heart. These results . . .