An analysis of inhibitory effect of cyclic GMP on arachidonic acid- or collagen-induced aggregation in rabbit platelets.
Aggregation of washed rabbit platelets induced by arachidonic acid (AA) or collagen was inhibited by nitroprusside (NP) and 8-bromo cyclic GMP in a concentration-dependent manner. Although NP and 8-bromo cyclic GMP inhibited the AA-induced aggregation, these agents did not affect the conversion of exogenous AA to PG endoperoxides and TXA2 (which were observed as TXB2). On the other hand, collagen caused release of AA from phospholipids and sequential formation of TXB2 in [14C]AA prelabeled platelets. In contrast with the case in which exogenous AA was used, NP and 8-bromo cyclic GMP inhibited the collagen-induced formation of TXB2 by preventing the liberation of endogenous AA. These results indicate that cyclic GMP has at least two different inhibitory actions in platelets; one is the inhibition of AA release from phospholipids and the other is the inhibition of the action of TXA2 in platelets.
Matsuoka
I
I
Nakanishi
H
H
D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism / Q000494:pharmacology*; D003094:Collagen / Q000494:pharmacology*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009599:Nitroprusside / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects*; D011817:Rabbits; D013928:Thromboxane A2 / Q000096:biosynthesis
D001095:Arachidonic Acids; D009599:Nitroprusside; D016718:Arachidonic Acid; C016276:8-bromocyclic GMP; D013928:Thromboxane A2; D003094:Collagen; D006152:Cyclic GMP