Platelet activating factor (PAF) and its role in cardiac injury.

PAF is a phospholipid formed from the action of phospholipase A2 triggered by immunologic or hypoxic stimuli. PAF does not exist in its active form but rather is present as a storage product within cells, and is synthesized rapidly upon appropriate activation. PAF is a potent lipid mediator which is released by a variety of cell types in mammalian systems. PAF appears to be a particularly important mediator of myocardial ischemia and circulatory shock states in mammalian species. Moreover, since PAF releases other lipid mediators, it may have an "amplifier" role in the propagation of circulatory disease states.