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The adrenaline beta-receptor blocking drug, pronethalol, and the sympathomimetic amines, (-)-ephedrine, (-)-amphetamine, dexamphetamine, (-)-Psi-ephedrine and tyramine, inhibited the sympathomimetic effects of butyrylcholine and tyramine on the guinea-pig isolated atrium. Being reversible and noncompetitive, this antagonism was unspecific and not due to blockade of adrenaline receptors, although pronethalol inhibited the effect of noradrenaline competitively.
Benfey et al. (1964) studied this question.