Differentiated storage mechanisms for noradrenaline and dopamine in the rabbit heart

Uptake and binding of dopamine and noradrenaline were studied in rabbit heart and brain after partial depletion of the amine stores with decaborane and inhibition of β-hydroxylation with disulfiram. Intravenous or intramuscular injection of noradrenaline and dopamine increased the noradrenaline content in partially noradrenaline-depleted hearts. After decaborane + disulfiram, 50 μg/kg noradrenaline intravenously still increased the noradrenaline content from 0.28 to 0.77 μg/g in 1 hr (P = < 0.001) whereas 100 μg/kg dopamine intravenously only increased the dopamine content from 0.016 to 0.105 μg/g in the same time. It is concluded that dopamine cannot effectively utilize the noradrenaline-binding sites made available after partial depletion by decaborane and inhibition of β-hydroxylation.