Elevation of cytosolic free Ca2+ is directly evoked by thromboxane A2 in human platelets during activation with collagen.
The thromboxane A2 antagonist, ONO-3708, completely inhibited the increase in cytosolic free Ca2+ in human platelets during activation with collagen. Half-maximal Ca2+ release and influx required about 3 and 4 nM STA2, a stable thromboxane A2 mimetic, respectively. However, half maximal activation of phospholipase C required about 18 nM STA2. This suggests that thromboxane A2 directly causes Ca2+ mobilization without further activation of phospholipase C during activation of human platelets with collagen.
Moriyama
T
T
Research Institute for Food Science, Kyoto University.
Takamura
H
H
Narita
H
H
Tanaka
K
K
Matsuura
T
T
Kito
M
M
D001792:Blood Platelets / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D003094:Collagen / Q000494:pharmacology*; D003600:Cytosol / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D066298:In Vitro Techniques; D010972:Platelet Activating Factor / Q000494:pharmacology*; D013928:Thromboxane A2 / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D010738:Type C Phospholipases / Q000378:metabolism
D010972:Platelet Activating Factor; D013928:Thromboxane A2; C049855:ONO 3708; D003094:Collagen; D010738:Type C Phospholipases; D002118:Calcium