In synaptosomes of the rat striatum the dopamine uptake was measured in a concentration range of 0.03 microM to 100 microM. In the presence of sodium the uptake exhibited a non-Michaelis-Menten kinetics and in a sodium-free medium the uptake kinetics was sigmoid. According to these findings a novel model for the dopamine uptake is proposed. Its main assumption is one carrier with two dopamine binding sites.