Adenosine diphosphate addition

Dismption of the endothehal surface of blood vessels expose coUagen fibers and connective tissue. These provide surfaces that promote platelet adherence, platelet release reaction, and subsequent platelet aggregation. Substances Hberated from the platelets stimulate further platelet aggregation, eg, adenosine diphosphate maintain vasoconstriction, eg, serotonin and participate in blood coagulation, eg, platelet Factors III and IV. In addition, the release reaction modifies platelet membranes in a manner that renders phosphoHpid available for coagulation. The thrombin [9002-04-4] elaborated by the coagulation mechanism is a potent agent in the induction of the platelet release reaction. 

Addition polymer Polymer produced by a monomer, usually a derivative of ethylene, adding to itself no other product is formed, 611-614,631q Addition reactions, 602 ADP (adenosine diphosphate), 469 Air... 

The formation of a platelet aggregate requires the recruitment of additional platelets from the blood stream to the injured vessel wall. This process is executed through a variety of diffusible mediators which act through G-protein-coupled receptors. The main mediators involved in this process are adenosine diphosphate (ADP), thromboxane A2 (TXA2), and thrombin (factor Ila). These mediators of the second phase of platelet activation are formed in different ways. While ADP is secreted from platelets by exocytosis, the release of TXA2 follows its new formation in activated platelets. Thrombin can be formed on the surface of activated platelets (see Fig. 2). 

Sulfinpyrazone is used in medicine as a nonsteroid anti-inflammatory, fever-reducing analgesic however, it is believed, that it inhibits cyclooxygenase of thrombocytes. In addition, it is also possible that its action is also linked with the action on membrane of thrombocytes and reduced quantities of secreted adenosine diphosphate and serotonin, which facilitate thrombocyte aggregation. Unlike aspirin, it has no effect on those who do not have irregular aggregation systems. 

Inhibition of the initial step of a biosynthetic pathway by an end product of the pathway is a recurrent theme in metabolic regulation. In addition, many key enzymes are regulated by ATP, adenosine diphosphate (ADP), AMP, or inorganic phosphate ion (Pi). The concentrations of these materials provide a cell with an index of whether energy is abundant or in short supply. Because ATP, ADP, AMP, or P often are chemically unrelated to the substrate of the enzyme that must be regulated, they usually bind to an allosteric site rather than to the active site. 

Adenosine, in addition to serving as a substrate for the generation of cAMP plays a physiologic role as a platelet inhibitor and a vasodilator and may attenuate neutrophil-mediated damage to endothelial cells, Adenosine diphosphate (ADP)— a potent platelet agonist—is converted to adenosine, which is taken up rapidly by cells, especially erythrocytes and endothelial cells, A small proportion is metabolized to the aforementioned cyclic nucleotides. The remainder is broken down to inosine and subsequently to xanthine. Dipyridamole inhibits the active transport of adenosine into cells, but does not interfere with the passive diffusion. Since the platelet inhibitory effects of adenosine proceed via stimulation of adenylate cyclase, these effects can also be amplified by dipyridamole, In circulating blood, the largest amount of adenosine is found in red blood cells, This may, in part, help explain why dipyridamole is much more effective in whole blood than in plasma. 

Table 1 summarizes the characteristics of several additional FET enzyme sensors. Enzymatically coupled FETs sensitive to acetylcholine (25), triglyceride (26), adenosine triphosphate (ATP) (40), adenosine diphosphate (ADP) (41), glutamate (27), and threonine (42) have been made. 

Shape change of the attached platelets, spreading along the fibrils permits multiple tight contacts with the matrix and there is simultaneous release of thromboxane-A2 (TXA2) and adenosine diphosphate (ADP) which recruit additional platelets. 

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