Kinetic evidence that the sodium-dependent high-affinity and the sodium-independent low-affinity dopamine uptake are mediated by one carrier.
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.
Berndt
C
C
Institute of Pathological and Clinical Biochemistry, Humboldt University, Medical School (Charité), Berlin, Germany.
Henke
W
W
Dubiel
W
W
Gross
J
J
D000818:Animals; D001665:Binding Sites; D001692:Biological Transport; D003342:Corpus Striatum; D004298:Dopamine / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000502:physiology*; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism
D012964:Sodium; D004298:Dopamine