resolvin E1>chemerin C-terminal peptide>18R-hydroxy-eicosapentaenoic acid (18R-EPE)>eicosapentaenoic acid (http://www.guidetopharmacology.org/GRAC/ObjectDisplayForward?objectId=79). Apparently, the resolvins activate this receptor in a different manner than chemerin: resolvins act through it to suppress while chemerin acts through it to stimulate pro-inflammatory responses in target cells Oxoeicosanoid Oxoeicosanoid: Oxoeicosanoid (OXE) receptor 1 – ; OXER1 is the receptor for 5-oxo-eicosatetraenoic acid (5-oxo-ETE) as well as certain other eicosanoids and long-chain polyunsaturated fatty acids that possess a 5-hydroxy or 5-oxo residue (see 5-Hydroxyeicosatetraenoic acid); relative potencies of the latter metabolites in binding to and activating OXER1 are: 5-oxoicosatetraenoic acid>5-oxo-15-hydroxy-eioxatetraenoic acid> 5S-hydroperoxy-eicosatetraenoic acid>5-Hydroxyeicosatetraenoic acid; the 5-oxo-eicosatrienoic and 5-oxo-octadecadienoic acid analogs of 5-oxo-ETE are as potent as 5-oxo-ETE in stimulating this receptor (http://www.guidetopharmacology.org/GRAC/ObjectDisplayForward?objectId=271). Activation of OXER1 is associated with pro-inflammatory and pro-allergic responses by cells and tissues as well as with the proliferation of various human cancer cell lines in culture. Prostanoid Prostanoids and Prostaglandin receptors Prostanoids are prostaglandins (PG), thromboxanes (TX), and prostacyclins (PGI). Seven, structurally-related, prostanoid receptors fall into three categories based on the cell activation pathways and activities which they regulate. Relaxant prostanoid receptors (IP, DP1, EP2, and EP4) raise cellular cAMP levels; contractile prostanoid receptors (TP, FP, and EP1) mobilize intracellular calcium; and the inhibitory prostanoid receptor (EP3) lowers cAMP levels. A final prostanoid receptor, DP2, is structurally related to the chemotaxis class of receptors and unlike the other prostanoid receptors mediates eosinophil, basophil, and T helper cell (Th2 type) chemotactic responses. Prostanoids, particularly PGE2 and PGI2, are prominent regulators of inflammation and allergic responses as defined by studies primarily in animal models but also as suggested by studies with human tissues and, in certain cases, human subjects. PGD2: DP-(PGD2) (PGD2 receptor) DP1 (PTGDR1) – ; DP1 is a receptor for Prostaglandin D2; relative potencies in binding to and activating DP1 for the following prostanoids are: PGD2>>PGE2>PGF2α>PGI2=TXA2 (http://www.guidetopharmacology.org/GRAC/ObjectDisplayForward?objectId=338). Activation of DP2 is associated with the promotion of inflammatory and the early stage of allergic responses; in limited set of circumstances, however, DP1 activation may ameliorate inflammatory responses. DP2 (PTGDR2) – ; DP2, also termed CRTH2, is a receptor for prostaglandin D2; relative potencies in binding to and stimulating PD2 are PGD2 >>PGF2α, PGE2>PGI2=TXA2 (http://www.guidetopharmacology.org/GRAC/ObjectDisplayForward?objectId=339&familyId=58&familyType=GPCR). While DP1 activation causes the chemotaxis of pro-inflammatory cells such as basophils, eosinophils, and T cell lymphocytes, its deletion in mice is associated with a reduction in an acute allergic responses in a rodent model. This and other observations suggest that DP2 and