The effect of pyridoxal-5-phosphate on the inhibition of platelet aggregation and adenosine-3'-5'-cyclic monophosphate accumulation in human platelets. 1984

M Zahavi, and J Zahavi, and V V Kakkar

Platelet adenosine-3'-5'-cyclic monophosphate (c-AMP) was determined in platelet rich plasma and washed platelets by a modification of the c-AMP protein binding assay. Studies were performed in the presence and absence of platelet aggregation inducers (adenosine diphosphate and thrombin) and inhibitors (pyridoxal-5-phosphate (PALP), prostaglandin E1 (PGE1), theophylline and papaverine). At 70% inhibitory concentration of platelet aggregation (PA) induced by papaverine or theophylline, a small but significant increase in platelet c-AMP level was found. With PALP however the inhibition of PA was not associated with a significant increase in the c-AMP level. PALP or theophylline potentiated greatly both the inhibition of PA and c-AMP accumulation induced by PGE1. Yet PALP potentiated the inhibition of PA induced by theophylline without increasing platelet c-AMP level. Our results indicate that the inhibition of PA by PALP is not mediated by c-AMP accumulation. However in the presence of PGE1, the increment in PA inhibition, is mediated by further indirect activation of the adenyl-cyclase.

UI MeSH Term Description Entries
D010208 Papaverine An alkaloid found in opium but not closely related to the other opium alkaloids in its structure or pharmacological actions. It is a direct-acting smooth muscle relaxant used in the treatment of impotence and as a vasodilator, especially for cerebral vasodilation. The mechanism of its pharmacological actions is not clear, but it apparently can inhibit phosphodiesterases and it may have direct actions on calcium channels. Cerespan,Papaverine Hydrochloride,Pavabid,Pavatym,Hydrochloride, Papaverine
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
D011458 Prostaglandins E (11 alpha,13E,15S)-11,15-Dihydroxy-9-oxoprost-13-en-1-oic acid (PGE(1)); (5Z,11 alpha,13E,15S)-11,15-dihydroxy-9-oxoprosta-5,13-dien-1-oic acid (PGE(2)); and (5Z,11 alpha,13E,15S,17Z)-11,15-dihydroxy-9-oxoprosta-5,13,17-trien-1-oic acid (PGE(3)). Three of the six naturally occurring prostaglandins. They are considered primary in that no one is derived from another in living organisms. Originally isolated from sheep seminal fluid and vesicles, they are found in many organs and tissues and play a major role in mediating various physiological activities. PGE
D011732 Pyridoxal Phosphate This is the active form of VITAMIN B 6 serving as a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, aminolevulinic acid. During transamination of amino acids, pyridoxal phosphate is transiently converted into pyridoxamine phosphate (PYRIDOXAMINE). Pyridoxal 5-Phosphate,Pyridoxal-P,Phosphate, Pyridoxal,Pyridoxal 5 Phosphate,Pyridoxal P
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
D000242 Cyclic AMP An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH. Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
D000527 Alprostadil A potent vasodilator agent that increases peripheral blood flow. PGE1,Prostaglandin E1,Caverject,Edex,Lipo-PGE1,Minprog,Muse,PGE1alpha,Prostaglandin E1alpha,Prostavasin,Prostin VR,Prostine VR,Sugiran,Vasaprostan,Viridal,Lipo PGE1
D013806 Theophylline A methyl xanthine derivative from tea with diuretic, smooth muscle relaxant, bronchial dilation, cardiac and central nervous system stimulant activities. Theophylline inhibits the 3',5'-CYCLIC NUCLEOTIDE PHOSPHODIESTERASE that degrades CYCLIC AMP thus potentiates the actions of agents that act through ADENYLYL CYCLASES and cyclic AMP. 1,3-Dimethylxanthine,3,7-Dihydro-1,3-dimethyl-1H-purine-2,6-dione,Accurbron,Aerobin,Aerolate,Afonilum Retard,Aquaphyllin,Armophylline,Bronchoparat,Bronkodyl,Constant-T,Elixophyllin,Euphylong,Glycine Theophyllinate,Lodrane,Monospan,Nuelin,Nuelin S.A.,Quibron T-SR,Slo-Phyllin,Somophyllin-T,Sustaire,Synophylate,Theo Von Ct,Theo-24,Theo-Dur,Theobid,Theocin,Theoconfin Continuous,Theodur,Theolair,Theolix,Theon,Theonite,Theopek,Theophylline Anhydrous,Theophylline Sodium Glycinate,Theospan,Theostat,Theovent,Uniphyl,Uniphyllin,Uniphylline,1,3 Dimethylxanthine,Anhydrous, Theophylline,Constant T,ConstantT,Ct, Theo Von,Glycinate, Theophylline Sodium,Quibron T SR,Quibron TSR,Slo Phyllin,SloPhyllin,Sodium Glycinate, Theophylline,Somophyllin T,SomophyllinT,Theo 24,Theo Dur,Theo24,Theophyllinate, Glycine,Von Ct, Theo
D013917 Thrombin An enzyme formed from PROTHROMBIN that converts FIBRINOGEN to FIBRIN. Thrombase,Thrombin JMI,Thrombin-JMI,Thrombinar,Thrombostat,alpha-Thrombin,beta,gamma-Thrombin,beta-Thrombin,gamma-Thrombin,JMI, Thrombin

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