“…As shown in Figure 1 , the synthesis of PGs and TX involves the hydrolysis of cellular phospholipids via the action of phospholipase A 2 (PLA 2 ) enzyme to produce free AA. AA is converted to unstable prostaglandin H 2 (PGH 2 ) by COX activity, and then to main prostanoids PGI 2 , TXA 2 , PGD 2 , PGE 2 and PGF 2 via their respective synthases PGIS, thromboxane A synthase (TXAS), prostaglandin D synthase (PGDS), prostaglandin E 2 synthases (PGESs) and prostaglandin F synthase (PGFS) ( 92 , 93 ). Currently, there are nine known prostanoid receptors expressed in different cell types, namely IP for PGI 2 , TP for TXA 2 , DP 1-2 for PGD 2 , EP 1-4 for PGE 2 , and FP for PGF 2 .…”