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INCREASES IN AGGREGATION BY AND UPTAKE OF 5‐HYDROXYTRYPTAMINE WITH PLATELETS FROM RABBITS TREATED WITH CHLORPROMAZINE
Author(s) -
CI M. BALDAC,
BALDACCI MARA,
BERGEL T.D.,
BORN G.V.R.,
HICKMAN MARGARET
Publication year - 1980
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.1476-5381.1980.tb10889.x
Subject(s) - chlorpromazine , platelet , chemistry , endocrinology , serotonin , medicine , adenosine diphosphate , platelet aggregation , pharmacology , biochemistry , receptor
1 Citrated platelet‐rich plasma was prepared from New Zealand white rabbits before, during and after administration of chlorpromazine (2 mg/kg) intramuscularly once daily for 3 to 4 weeks. 2 In these plasmas, the velocity of platelet aggregation by 5‐hydroxytryptamine (5‐HT) added at 1, 3 and 10 μ m increased greatly, beginning 3 to 4 days after the start of chlorpromazine injections and lasting for a similar period after they were terminated The increase had two maxima, the first after 6 to 10 days and the second after 17 to 24 days. Chlorpromazine treatment did not affect aggregation by adenosine diphosphate (ADP). 3 The uptake of 5‐HT by rabbit platelets was very fast and linear for less than 10 s. In platelets from untreated rabbits the uptake had a K m of 0.35 ± 0.08 μ m and a V max of 39.8 ± 6.1 pmol 10 −8 platelets 10 −1 ( n = 5). 4 In platelets from rabbits injected with chlorpromazine (see (2) above) both kinetic constants increased significantly, the K m to 0.88 ± 0.08 μ m and the V max to 67.8 ± 5.5 pmol. 10 −8 platelets. 10 −1 s ( n = 9).