ADP, or Adenosine diphosphate, in haematology is a chemical released by platelets that plays a crucial role in blood clot formation.
Here's a more detailed explanation:
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Role in Platelet Aggregation: ADP is a potent platelet agonist. This means it stimulates platelets, causing them to change shape, activate, and adhere to each other – a process called platelet aggregation. This aggregation is essential for forming a stable blood clot at the site of an injury.
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Mechanism of Action: Platelets have receptors on their surface, primarily P2Y1 and P2Y12, which bind to ADP. Binding of ADP to these receptors triggers a cascade of intracellular signaling events that lead to platelet activation and aggregation.
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Clinical Significance: Because ADP is crucial for platelet function, antiplatelet drugs, like clopidogrel and prasugrel, target the P2Y12 receptor. These drugs block ADP from binding to the P2Y12 receptor, thereby inhibiting platelet aggregation and reducing the risk of blood clots in conditions like heart attack and stroke. The P2Y1 receptor also plays a role in platelet shape change and initial activation.
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ADP Storage and Release: Platelets contain granules that store ADP. When platelets are activated by injury signals (like collagen exposure), they release ADP, which then further activates other platelets, amplifying the aggregation response.
In summary, ADP is a key mediator of platelet activation and aggregation, essential for haemostasis (stopping bleeding) and thrombosis (blood clot formation). Understanding its role is crucial in developing and using antiplatelet therapies.
