Human lymphocytes possess a cocaine-sensitive high-affinity transport system for [ 3 H]dopamine. [ 3 H]Dopamine uptake was saturated with increasing dopamine concentrations and followed Michaelis-Menten kinetics. The uptake was temperature, sodium, and chloride dependent and was affected by the co-addition of ouabain, phloridzin, potassium cyanide, gramicidin, and other metabolic inhibitors. The uptake of dopamine was blocked significantly in a concentration-dependent manner by cocaine and its congeners. Furthermore, preliminary evidence is presented linking the possible relationship between decreased lymphocyte [ 3 H]dopamine uptake and chronic cocaine abuse in humans.
Zbigniew L. Olkowski, MD 