Prostaglandin A1 inhibits increases in intracellular calcium concentration, TXA(2) production and platelet activation.
OBJECTIVE
In our previous studies we found that cyclopentenane prostaglandin A1 (PGA1) had neuroprotective effects in a rodent ischemic model. In the present study we aimed to investigate the inhibitory effect of PGA1 on platelet function.


METHODS
The rate of aggregation of human platelets was measured by using turbidimetry. The rate of adhesion of platelets to cultured endothelial cells was determined by using [(3)H]-adenine labeled platelets. 5-Hydroxytryptamine release from platelets was measured with O-phthaldialdehyde fluorospectrophotometry. The levels of TXB(2), a stable metabolite of TXA(2), were determined by radioimmuno-assay. Alternations in platelet morphology were observed using an electron microscope, and the intraplatelet free calcium concentrations were measured with Fluo-3/AM FCM assay.


RESULTS
PGA1 significantly inhibited thrombin-, collagen- and ADP-induced aggregation and adhesion of platelets. The morphological changes of platelets induced by thrombin were blocked by PGA1. PGA1 inhibited the release of 5-hydroxytyptamine from dense granules and the synthesis of TXA(2).


CONCLUSIONS
PGA1 inhibits the activation of platelets probably through blocking increases in intracellular calcium concentration and TXA(2) synthesis.
Zhu
Yi
Y
Department of Pharmacology, Soochow University School of Medicine, Suzhou 215123, China.
Gu
Zhen-Lun
ZL
Liang
Zhong-Qin
ZQ
Zhang
Hui-Lin
HL
Qin
Zheng-Hong
ZH
D000244:Adenosine Diphosphate / Q000037:antagonists & inhibitors; D001792:Blood Platelets / Q000187:drug effects; D002118:Calcium / Q000097:blood*; D003094:Collagen / Q000037:antagonists & inhibitors; D006801:Humans; D010973:Platelet Adhesiveness / Q000187:drug effects*; D010974:Platelet Aggregation / Q000187:drug effects*; D011454:Prostaglandins A / Q000494:pharmacology*; D012701:Serotonin / Q000097:blood; D013917:Thrombin / Q000037:antagonists & inhibitors; D013928:Thromboxane A2 / Q000096:biosynthesis*
D011454:Prostaglandins A; D012701:Serotonin; D013928:Thromboxane A2; D000244:Adenosine Diphosphate; D003094:Collagen; D013917:Thrombin; D002118:Calcium; C100573:prostaglandin A1