An assay to measure the simultaneous uptake of [3H]dopamine and [14C]serotonin by the human platelet reveals an imipramine-insensitive [3H]dopamine uptake mechanism.
To determine whether a specific dopamine uptake mechanism is present on the human platelet the simultaneous uptake of [3H]dopamine and [14C]serotonin by platelets was measured. Utilising a dual radiolabel uptake technique, platelets have been shown to take up serotonin more rapidly and to a greater extent than they take up dopamine. Furthermore, at high concentrations serotonin was able to reduce dopamine uptake by platelets by 60% whereas dopamine had no effect on serotonin uptake. Similarly, imipramine and reserpine reduced (97% and 74% respectively) serotonin uptake by platelets in a dose-dependent manner, but did not affect the uptake of dopamine. Our data show that platelets take up dopamine by a mechanism independent of the imipramine-sensitive serotonin uptake mechanism. Furthermore, the increased capacity of platelets to store serotonin is because serotonin, unlike dopamine, is transported into the dense granules of the platelet.
Dean
B
B
Neurochemistry Unit, Royal Park Hospital, Parkville, Victoria, Australia.
Copolov
D L
DL
D001692:Biological Transport / Q000187:drug effects; D001792:Blood Platelets / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D006801:Humans; D007099:Imipramine / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D012110:Reserpine / Q000494:pharmacology; D012701:Serotonin / Q000378:metabolism*
D012701:Serotonin; D012110:Reserpine; D007099:Imipramine; D004298:Dopamine