Evaluation of the uptake of various amines into storage vesicles of intact human platelets.
1 The uptake of various 3H-labelled amines into a thrombin-releasable compartment of human platelets, thought to represent the platelet vesicular storage pool, has been evaluated. Measurable amounts of 5-hydroxytryptamine (5-HT), dopamine, tyramine, octopamine, and tryptamine accumulate in this pool, and also in a non-thrombin-releasable (cytoplasmic) pool during a 30 min incubation period with 10(-5) M extracellular amine concentrations. 2 No differences in the accumulation of vesicular or cytoplasmic 5-HT, dopamine, and tyramine are found in platelets treated with deprenyl to inhibit platelet monoamine oxidase as compared to controls. 3 Extracellular tyramine or dopamine in concentrations as high as 10(-5) M does not alter the initial rate of 5-HT uptake across the platelet plasma membrane. Similarly, sizable cytoplasmic pools of either amine do not alter the initial rate at which small amounts of 5-HT enter platelet cytoplasm or storage vesicles. 5-HT thus appears to be the preferred substrate for uptake into platelets and for movement from cytoplasm to vesicles.
D001679:Biogenic Amines / Q000097:blood*; D001792:Blood Platelets / Q000378:metabolism* / Q000648:ultrastructure; D003593:Cytoplasm / Q000378:metabolism; D004298:Dopamine / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008566:Membranes / Q000378:metabolism; D012701:Serotonin / Q000097:blood / Q000494:pharmacology; D014439:Tyramine / Q000494:pharmacology
D001679:Biogenic Amines; D012701:Serotonin; D004298:Dopamine; D014439:Tyramine