Presence and characterization of the dopamine transporter in human resting lymphocytes

The paucity of information on the presence of the dopamine transporter (DAT) in blood cells, prompted us to explore it in human resting lymphocytes by means of the binding of 3H-WIN 35,428, a compound which is currently considered the most selective ligand for labelling this protein, and by means of the specific reuptake of 3H-dopamine (3H-DA). Lymphocytes were obtained by 15 healthy subjects. The results showed the presence of a specific and saturable binding of 3H-WIN 35,428, which labelled one site only. A specific 3H-DA reuptake was also measured. The pharmacological characterization of both binding and reuptake was overlapping. These findings would indicate that human resting lymphocytes carry the DAT, whose functions in periphery are still unknown.