Aspirin - mechanism of action, acetylsalicylic acid action mechanism
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7 سال پیش
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1. Mechanism of action: Stimulation
1. Mechanism of action: Stimulation of platelets by thrombin, collagen, and ADP results in activation of platelet membrane phospholipases that liberate arachidonic acid from membrane phospholipids.
Arachidonic acid is frst converted to prostaglandin H2 by COX-1
(Figure 22.6). Prostaglandin H2 is further metabolized to thromboxane A
2, which is released into plasma. Thromboxane A2 promotes
the aggregation process that is essential for the rapid formation of
a hemostatic plug. Aspirin [AS-pir-in] inhibits thromboxane A2 synthesis by acetylation of a serine residue on the active site of COX-1,
thereby irreversibly inactivating the enzyme (Figure 22.7). This
shifts the balance of chemical mediators to favor the antiaggregatory effects of prostacyclin, thereby preventing platelet aggregation.
The inhibitory effect is rapid, and aspirin-induced suppression of
thromboxane A
2 and the resulting suppression of platelet aggrega
tion last for the life of the platelet, which is approximately 7 to 10 days.
Repeated administration of aspirin has a cumulative effect on the
function of platelets. Aspirin is the only antiplatelet agent that irre
versibly inhibits platelet function.
Arachidonic acid is frst converted to prostaglandin H2 by COX-1
(Figure 22.6). Prostaglandin H2 is further metabolized to thromboxane A
2, which is released into plasma. Thromboxane A2 promotes
the aggregation process that is essential for the rapid formation of
a hemostatic plug. Aspirin [AS-pir-in] inhibits thromboxane A2 synthesis by acetylation of a serine residue on the active site of COX-1,
thereby irreversibly inactivating the enzyme (Figure 22.7). This
shifts the balance of chemical mediators to favor the antiaggregatory effects of prostacyclin, thereby preventing platelet aggregation.
The inhibitory effect is rapid, and aspirin-induced suppression of
thromboxane A
2 and the resulting suppression of platelet aggrega
tion last for the life of the platelet, which is approximately 7 to 10 days.
Repeated administration of aspirin has a cumulative effect on the
function of platelets. Aspirin is the only antiplatelet agent that irre
versibly inhibits platelet function.
7 سال پیش
در تاریخ 1396/04/30 منتشر شده
است.
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