Biomaterial Database

Effects of RP and SP diastereoisomers of adenosine 5'-O-(1-thiodiphosphate) on human platelets. 1981

N J Cusack, and S M Hourani

1 RP and SP diastereoisomers of adenosine 5'-O-(1-thiodiphosphate) ((R)-ADP-alpha-S and (S)-ADP-alpha-S), an adenosine 5'-diphosphate (ADP) analogue, were tested on intact human platelets. 2 Each diastereoisomer induced aggregation, (S)-ADP-alpha-S being 5 times more potent than (R)-ADP-alpha-S but they achieved only 75% of the maximal effect of ADP. 3 Aggregation induced by each diastereoisomer was competitively inhibited by ATP (50 microM). 4 Simultaneous addition of each diastereoisomer inhibited aggregation induced by ADP but not by 11 alpha, 9 alpha-epoxymethano prostaglandin H2, a stable endoperoxide analogue. Both diastereoisomers are therefore partial agonists at the ADP receptor mediating aggregation. 5 Unlike ADP, neither diastereoisomer inhibited prostaglandin E1 (PGE1)-stimulated adenylate cyclase, but each competitively inhibited the effect of aDP, with (S)-ADP-alpha-S again being 5 times more potent than (R)-ADP-alpha-S. 6 These are the first reported examples of ADP analogues to induce platelet aggregation without inhibiting PGE1-stimulated adenylate cyclase.

UI	MeSH Term	Description	Entries
D009711	Nucleotides	The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King & Stansfield, A Dictionary of Genetics, 4th ed)	Nucleotide
D010974	Platelet Aggregation	The attachment of PLATELETS to one another. This clumping together can be induced by a number of agents (e.g., THROMBIN; COLLAGEN) and is part of the mechanism leading to the formation of a THROMBUS.	Aggregation, Platelet
D011463	Prostaglandins H	A group of physiologically active prostaglandin endoperoxides. They are precursors in the biosynthesis of prostaglandins and thromboxanes. The most frequently encountered member of this group is the prostaglandin H2.
D001792	Blood Platelets	Non-nucleated disk-shaped cells formed in the megakaryocyte and found in the blood of all mammals. They are mainly involved in blood coagulation.	Platelets,Thrombocytes,Blood Platelet,Platelet,Platelet, Blood,Platelets, Blood,Thrombocyte
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000244	Adenosine Diphosphate	Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.	ADP,Adenosine Pyrophosphate,Magnesium ADP,MgADP,Adenosine 5'-Pyrophosphate,5'-Pyrophosphate, Adenosine,ADP, Magnesium,Adenosine 5' Pyrophosphate,Diphosphate, Adenosine,Pyrophosphate, Adenosine
D000262	Adenylyl Cyclases	Enzymes of the lyase class that catalyze the formation of CYCLIC AMP and pyrophosphate from ATP.	Adenyl Cyclase,Adenylate Cyclase,3',5'-cyclic AMP Synthetase,Adenylyl Cyclase,3',5' cyclic AMP Synthetase,AMP Synthetase, 3',5'-cyclic,Cyclase, Adenyl,Cyclase, Adenylate,Cyclase, Adenylyl,Cyclases, Adenylyl,Synthetase, 3',5'-cyclic AMP
D013237	Stereoisomerism	The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)	Molecular Stereochemistry,Stereoisomers,Stereochemistry, Molecular,Stereoisomer
D013873	Thionucleotides	Nucleotides in which the base moiety is substituted with one or more sulfur atoms.
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In