Inhibition of platelet secretion of ATP by phalloidin.
The involvement of actin in the secretion of ATP by platelets was studied using two stimulants, ADP and A23187, and two actin-mediating reagents, cytochalasin B and phalloidin. The degree of actin polymerization was determined using DNase I. Preincubation of platelets with cytochalasin B suppressed the polymerization of actin and ATP secretion induced by stimulants. In the absence of the stimulant, phalloidin-treated platelets exhibited time-dependent actin polymerization and the maximum level was reached at 5 min. No secretion of ATP was observed. The polymerization was enhanced by phalloidin when the platelets were preincubated for 3 to 5 min with the stimulants, but little ATP was secreted. After a 30-min preincubation, the amount of polymerized actin was lower than that after a 5-min incubation, and no ATP was secreted.
Hashimoto
K
K
Kawarabayashi
K
K
Hashimoto
K
K
Tatsumi
N
N
D000199:Actins / Q000097:blood; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000097:blood*; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D046911:Macromolecular Substances; D009842:Oligopeptides / Q000494:pharmacology*; D010590:Phalloidine / Q000494:pharmacology*
D000199:Actins; D046911:Macromolecular Substances; D009842:Oligopeptides; D010590:Phalloidine; D000001:Calcimycin; D003571:Cytochalasin B; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate