Platelet Activating Factor
Platelet activating factor is a protein present in a variety of cells throughout the body that participates in the activation of platelet, leukocyte, and PLA2, which results in inflammatory and thrombotic mechanisms. Many cell types produce platelet-activating factor (1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine [PAF]), a powerful lipid autocoid. When injected in vivo, PAF has a strong effect on brain arteries and metabolism. PAF has direct neuronal actions in vitro, such as suppression of acetylcholine release. Excessive PAF production has been demonstrated in pathogenic nervous system conditions such as neurotrauma and stroke (Yue & Feuerstein, 1994) . PAF synthesis and release may be enhanced in SAH as a result of activated immune cells and endothelial cells driven by thrombin and IL-1 (Khey, Huard & Mahmoud, 2020). PAF produces tissue edema by increasing vascular permeability in peripheral tissues, boosting platelet production of granule-based enzymes, and increasing superoxide and arachidonate metabolism in neutrophils, culminating in neurotoxicity and brain damage following an ischemic stroke (Bladowski, Gawrys, Gajecki, Szahidewicz-Krupska, Sawicz-Bladowska & Doroszko, 2020; Lindsberg, Hallenbeck & Feuerstein, 1991; Zimmerman, McIntyre, Mehra & Prescott, 1990).