The kinetics of chondroitin 4-sulfate release from stimulated platelets and its relation to thromboxane A2 formation and granule secretion.
1. In platelet rich plasma (PRP), chondroitin 4-sulfate release from platelets occurred after stimulation with ADP (5 microM), collagen (5-10 micrograms/ml), or adrenaline (10 microM). Release started within 60 s and maximum release (0.7-2.0 mg/l) was reached within 180 s. TXA2 formation and dense granule release reached a maximum within 90 s after stimulation. 2. Using washed platelets (1.5 x 10(8) cells/ml), the platelet responses were faster. Release of chondroitin 4-sulfate and TXA2 started within 20-30 s after thrombin addition (100 mU/ml). Maximum release was reached within 60 s in both cases. Dense granule release started in the first 5 s of stimulation (34.6 +/- 12.4%) reaching maximum secretion (74.4 +/- 8.7%) within 60 s. 3. Our results demonstrate that maximal chondroitin 4-sulfate release occurs after the dense granule release reaction in both PRP and washed platelets. This observation suggests that chondroitin 4-sulfate is unlikely to be stored in the dense granules but may be stored in the alpha-granules.
Donato
J L
JL
Departamento de Farmacologia, Faculdade de Ciências Médicas, UNICAMP, SP, Brasil.
Nogueira
M D
MD
Marcondes
S
S
Antunes
E
E
Nader
H B
HB
Dietrich
C P
CP
de Nucci
G
G
D000244:Adenosine Diphosphate / Q000494:pharmacology; D001792:Blood Platelets / Q000737:chemistry* / Q000187:drug effects; D002809:Chondroitin Sulfates / Q000378:metabolism*; D003094:Collagen / Q000494:pharmacology; D003594:Cytoplasmic Granules / Q000378:metabolism*; D006801:Humans; D010974:Platelet Aggregation / Q000187:drug effects; D013917:Thrombin / Q000494:pharmacology; D013928:Thromboxane A2 / Q000096:biosynthesis*; D013997:Time Factors
D013928:Thromboxane A2; D000244:Adenosine Diphosphate; D002809:Chondroitin Sulfates; D003094:Collagen; D013917:Thrombin