What is Pathology - What is platelet-activating factor (PAF) and how does it work?

What is Pathology - What is platelet-activating factor (PAF) and how does it work?
​ PAF is a multifunctional, physiologically active molecule that was first described as a phospholipid-derived mediator of platelet aggregation and degranulation. It affects a large number of cells. Leukocytes, endothelial cells, and a variety of other cells produce it. PAF receptors can be found on a wide range of cells, all of which can react when exposed to this mediator. It can produce bronchospasm and vasospasm, as well as vasodilation and increased vascular permeability, for example.