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UPTAKE OF 6‐FLUORO‐5‐HYDROXYTRYPTAMINE AND 4,6‐DIFLUORO‐5‐HYDROXYTRYPTAMINE INTO RELEASABLE AND NON‐RELEASABLE COMPARTMENTS OF HUMAN PLATELETS
Author(s) -
COSTA J.L.,
KIRK K.L.,
STARK H.
Publication year - 1982
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1982.tb08778.x
Subject(s) - platelet , chemistry , compartment (ship) , incubation , biophysics , serotonin , biochemistry , biology , immunology , oceanography , receptor , geology
1 The ring‐fluorinated compounds, 6‐fluoro‐5‐hydroxytryptamine and 4,6‐difluoro‐5‐hydroxytryptamine, are sterically similar to 5‐hydroxytryptamine (5‐HT) but have pK a s for their 5‐hydroxyl groups (9.7 and 8.0 respectively) which are lower than that of 5‐HT. 2 The rates at which [ 3 H]‐5‐HT, [ 3 H]‐6‐fluoro‐5‐HT, and [ 3 H]‐4,6‐difluoro‐5‐HT entered the releasable (vesicular) and non‐releasable compartments of washed human platelets during a 1 min incubation period at 37°C were similar. These portions of the uptake process therefore appear to be relatively independent of the pK a of the 5‐hydroxyl group. 3 The [ 3 H]‐4,6‐difluoro‐5‐HT was unique since material accumulating in the non‐releasable compartment during uptake did not migrate into the vesicular compartment under appropriate incubation conditions. 4 The data suggest that the zwitterionic form of 5‐HT is not the transported species, but that the electronic configuration about the 5‐hydroxyl group may be critical for translocation from a non‐releasable to a releasable compartment.