POTENTIATION OF SOME CATECHOL AMINES BY PHENOXYBENZAMINE, GUANETHIDINE AND COCAINE

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Abstract
In rabbit isolated atria, cocaine, guanethidine and phenoxybenzamine increased the changes in rate and force of contractions caused by noradrenaline and adrenaline, but did not potentiate isoprenaline. The most likely explanation for this result is that the drugs interfere with one of the mechanisms in the heart by which noradrenaline and adrenaline, but not isoprenaline, are inactivated; a probable mechanism would be the uptake of noradrenaline into storage sites in the tissue. Cocaine, guanethidine and phenoxybenzamine did not potentiate noradrenaline and adrenaline acting on the rabbit isolated duodenum and the rat uterus.