Release and Uptake of Dopamine in Isolated Granules from a Human Carotid Body Tumour

Isolated granules from a human carotid body tumour incubated in 130 mM K‐phosphate pH 7.5 release dopamine (DA) with a half time of 23 min at 37° C. Addition of DA 2times10‐5M to the incubation fluid prevents net loss of DA from the granules, owing to reuptake. Further addition of ATP‐Mg2+increases the DA content in the granules about 8 times. This effect is strongly inhibited by reserpine 10‐3M and reduced about 40 per cent by noradrenaline (NA) and adrenaline (A) each in a concentration of 10‐5M.