Dissociation of potentiation of isoprenaline by cocaine from inhibition of uptake in cat spleen

Abstract

1 . Cocaine hydrochloride, 10 μg/ml, potentiated isoprenaline and noradrenaline in isolated spleen strips from normal cats and from cats treated with reserpine 24 h previously. 2 . Isoprenaline was taken up almost as well as noradrenaline by spleen strips from cats treated with reserpine. 3 . Cocaine blocked uptake of noradrenaline but did not reduce uptake of isoprenaline. Drug concentrations used in these studies were the same as in potentiation experiments. 4 . It is concluded that inhibition of uptake is not the mechanism by which cocaine potentiates the effect of isoprenaline on the spleen and might be only a contributory factor in the case of noradrenaline potentiation.