What role does cAMP play in platelet activation?
What role does cAMP play in platelet activation?
cAMP activates protein kinase A (PKA) which has several substrates in platelets, one of them being the inosital triphosphate (IP 3 ) receptor. Phosphorylation of this receptor by PKA inhibits calcium release from the dense tubular system.
Does ADP promote platelet activation?
ADP is the first known and an important agonist for platelet aggregation. ADP also induces platelet shape change, secretion from storage granules, influx and intracellular mobilization of Ca2+, and inhibition of stimulated adenylyl cyclase activity.
What is ADP cAMP?
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What is ADP in platelet plug formation?
ADP: The chemical structure of ADP, a molecule that causes platelet activation and is involved in the positive feedback component of platelet activation. The other factors released during platelet activation perform other important functions.
How does increased cAMP inhibit platelet aggregation?
ARC69931MX and clopidogrel by cAMP levels can inhibit human platelet aggregation through the activation of a separate G protein-coupled pathway (presumably involving Gs) and platelet P2Y12 receptor, respectively [51, 52].
How does cGMP inhibit platelet aggregation?
Stimulation of cGK by cGMP leads to phosphorylation of multiple target substrates. These substrates inhibit elevation of intracellular calcium, integrin activation, cytoskeletal reorganization, and platelet granule secretion, events normally associated with platelet activation.
How does ADP promote platelet aggregation?
Following adhesion, platelets are activated by a number of agonists such as adenosine diphosphate (ADP) and collagen present at the sites of vascular injury. These agonists activate platelets by binding to specific receptors on the platelet surface discussed earlier.
What is the function of ADP in platelets?
Adenosine diphosphate (ADP) is a platelet agonist that causes platelet shape change and aggregation as well as generation of thromboxane A2, another platelet agonist, through its effects on P2Y1, P2Y12, and P2X1 receptors.
What is the role of ADP in coagulation?
While the adenosine 5′-diphosphate (ADP) pathway is known to enhance thrombus formation by recruiting platelets and leukocytes to the primary layer of collagen-adhering platelets, its role for the initiation of coagulation has not been revealed.
What causes ADP to be released from platelets?
ADP and platelet activation. Platelet activation by potent agonists such as thrombin or collagen causes the release of secondary agonists such as thromboxane A2(TxA2) and the secretion of ADP from platelet dense granules.
What is the mechanism of action of ADP?
The end of the beginning. ADP is actively secreted from platelet dense granules but is also passively released from damaged erythrocytes and endothelial cells. Most platelet agonists, including ADP, activate platelets via cell surface receptors coupled to heterotrimeric GTP-binding proteins or G proteins.
How do platelet agonists activate platelets?
Most platelet agonists, including ADP, activate platelets via cell surface receptors coupled to heterotrimeric GTP-binding proteins or G proteins. Platelets contain representatives of all four of the known families of G proteins: G q, G i, G 12, and G s.
How does thrombin activate platelets?
Platelet activation by potent agonists such as thrombin or collagen causes the release of secondary agonists such as thromboxane A2(TxA2) and the secretion of ADP from platelet dense granules. Platelet responses to ADP require the coordinate activation of two G protein–coupled receptors, P2Y1 and P2Y12, whose actions are described in the text.
