Vesicular storage of 3,4-dihydroxyphenylethylamine and noradrenaline in terminal sympathetic nerves of dog spleen and kidney.

The subcellular distribution of 3,4-dihydroxyphenylethylamine (DA, dopamine) and noradrenaline was examined in preparations of dog spleen and renal cortex following ultracentrifugation on a discontinuous sucrose gradient. In both tissues, only half the total tissue DA was localized to the soluble phase, and 30-50% was found in association with noradrenaline in the large vesicular fraction, suggesting that both catecholamines may be stored together and released by nerve stimulation. The vesicular fraction from renal cortex contained more DA than could be attributed to its presence in noradrenergic axons alone, supporting other evidence for the existence of dopaminergic renal nerves.