Negative inotropic effect of sympathomimetic amines in rabbit atria.

for geriatric patients. The negative inotropic effect of sympathomimetic amines has scarcely been reported in rature. Wenzel and Su (3), while studying the interactions of sympathomimetic amines with ir antagonists on isolated rat ventricular strips, observed that phenylephrine initially produceda negative inotropic effect which was later on followed by usual positive inotropic response. imilarlyepinephrine produced an initial depression of contractile amplitude when administered mpresence of nethalide, a beta blocker. He attributed this inhibitory response to activation of alphainhibitory receptors, whose existence till then was unclaimed. The usual positive inotropic responsefollowing initial inhibition was supposedly due to stimulation of alpha excitatory receptors. ticonvulsant activity of 2,3-disubstituted s., 45(2): 207-211, 1957. "Methods in Enzymo!ogy Vo! I" C I5, 1955. ,. , 0 0-