Different effects of two thromboxane A2/prostaglandin H2 receptor ligands, U46619 and S-145, on rabbit platelets.
Stimulation of rabbit platelets with U46619 induced platelet shape change, aggregation and secretion of ATP. However, S-145, which specifically binds to the thromboxane A2/prostaglandin H2 receptor like U46619, induced only shape change. Both compounds rapidly elevated cytoplasmic Ca2+ concentration although only U46619 evoked the formation of inositol phosphates. Chelating external Ca2+ with EGTA did not affect the S-145-induced platelet shape change while intracellular Ca2+ movement was severely reduced. These results suggest an essential role of phospholipase C in the induction of platelet aggregation and secretion and that some factor other than Ca2+ and phospholipase C participates in platelet shape change.
Nakano
T
T
Shionogi Research Laboratories, Shionogi & Co., Ltd., Osaka, Japan.
Hanasaki
K
K
Arita
H
H
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000255:Adenosine Triphosphate / Q000097:blood; D000818:Animals; D001792:Blood Platelets / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D001643:Bridged Bicyclo Compounds / Q000494:pharmacology*; D001952:Bridged-Ring Compounds / Q000494:pharmacology*; D002118:Calcium / Q000097:blood; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology*; D007295:Inositol Phosphates / Q000097:blood; D007700:Kinetics; D010974:Platelet Aggregation; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology*; D011463:Prostaglandins H / Q000378:metabolism; D011817:Rabbits; D011982:Receptors, Prostaglandin / Q000378:metabolism; D017482:Receptors, Thromboxane; D044244:Receptors, Thromboxane A2, Prostaglandin H2; D013928:Thromboxane A2 / Q000378:metabolism
D001643:Bridged Bicyclo Compounds; D001952:Bridged-Ring Compounds; D005229:Fatty Acids, Monounsaturated; D007295:Inositol Phosphates; D011450:Prostaglandin Endoperoxides, Synthetic; D011463:Prostaglandins H; D011982:Receptors, Prostaglandin; D017482:Receptors, Thromboxane; D044244:Receptors, Thromboxane A2, Prostaglandin H2; C056566:S 145; D013928:Thromboxane A2; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000255:Adenosine Triphosphate; D002118:Calcium