Production of Bradycardia in Normal Man by Neosynephrin ∗ (1-α-hydroxy-β-methylamino-3-hydroxy-ethylbenzene hydrochloride)

Summary

Neosynephrin injected subcutaneously into normal, trained subjects in the basal state produces an immediate bradycardia and rise in diastolic pressure; systolic pressure rises later. The threshold is from 1 to 2.5 mg and pulse rates from 30 to 45, persisting for as long as 80 minutes, are produced by 5 to 10 mg. The E.C.G. remains normal with no change in A.V. or ventricular conduction time but there is a fall in the potential of the P wave and a rise in the T wave.