What does platelet-activating factor cause?

Platelet-activating factor (PAF) is a potent phospholipid mediator that was first described by its ability to cause platelet aggregation and dilation of blood vessels. Now it is also known as a potent mediator of inflammation, allergic responses, and shock.

Does platelet-activating factor cause vasoconstriction?

PAF has potent pathophysiologic effects and contributes to inflammation, endotoxic shock, and allergic reactions (asthma) through vasoconstriction, bronchoconstriction, platelet aggregation, and leukocyte adhesion, chemotaxis, and degranulation.

What cells release platelet-activating factor?

PAF is synthesized and released from various immune cells, including neutrophils, monocytes, macrophages, platelets, eosinophils, and vascular endothelial cells [1], and accumulating evidence indicates that PAF is involved in inflammation and coagulation through its specific receptor expressed on a wide variety of cell …

What happens during platelet activation?

Platelet activation represents a central moment in the process that leads to thrombus formation. When endothelial damage occurs, platelets come into contact with exposed collagen and von Willebrand factor, becoming activated. They are also activated by thrombin or by a negatively charged surface, such as glass.

What activates platelets and how do they behave after activation?

Thrombin causes proteolytic cleavage of fibrinogen, induces platelet activation, and triggers a wide range of effects secondary to thrombosis; for example, vascular smooth muscle cell and fibroblast proliferation, monocyte chemotaxis, and neutrophil adhesion.

What does PAF mean?

Patent Applied For
P.A.F. is an acronym for Patent Applied For and is a nickname given to the original Gibson humbuckers designed in 1955. These pickups had a sticker on the bottom that had “Patent Applied For” on them and years later the name was shortened by musicians to P.A.F.

What is platelet activation?

Platelet activation is a key process in both protective hemostasis and pathological thrombosis through the activation of multiple pathways by the binding of several agonists (e.g., thromboxane A2 (TxA2), adenosine diphosphate (ADP), and thrombin) to their receptors (Figure 25.1).

Is Platelet Activating Factor a mediator?

Platelet-activating factor (PAF) is a phospholipid with potent, diverse physiological actions, particularly as a mediator of inflammation.

When do platelets activate?

Platelets are normally activated in the presence of tissue injury with endothelial disruption and loss of activation inhibitors, exposure of the von Willebrand factor that binds it’s receptor and slows circulating platelets, and release of ADP, thrombin, and TxA2 as well as binding of fibrinogen or collagen to αIIb/β3.

How many days do platelets live?

They are then released from your bone marrow into your blood, and travel around the body in your bloodstream. Platelets usually survive for 7 to 10 days, before being destroyed naturally in your body or being used to clot the blood.