Eicosanoid Receptors

An excellent historical de.scription of prostanoid receptor i.sulation and characterization has been published, and a more recent review of developments in this field is available. Basically, pro.stanoid receptors are identified by their primary eicosonoid agonist (e.g., DP, EP, IP, and TP), although subclassification of PGE receptors has been neces- 

Although receptor studies have required the use of nonhuman species (principally the mouse but also Ihe rat. cow. sheep, and rabbit I. a high correlation of structural homology of receptor subtypes between species (—80 to 9nVr) has been observed, while structural homology among receptor sub- 

Receptor Principle Ligands TissuefAction Transduction Gene Knockout Effect 

FP PGF.v. Hyc/ lecrcasc intraocular pressure tPI lumover/Gt, Lost panuritton 

This produet, whieh was supplied a.s a. solution of the unmethamine. salt (S mg/niL) for direet adntinistration. is no lunger available in the United States for human use but IS still formulated for veterinary use as deseribed elsewhere in this chapter. 

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Splice variants for the eicosanoid receptors are indicated where appropriate. 

Eicosanoids are lipids derived from arachidonic acid they inclnde the prostaglandins, prostacyclins, thromboxanes and lenkotrienes. In hnmans, eicosanoids are local hormones that are released by most cells, act on those same cells or nearby cells (i.e. they are autocrine and paracrine mediators), and then are rapidly inactivated. Eicosanoids have a short half-life, ranging from seconds to minntes. They exert complex control over many bodily systems, mainly in inflammation or immnnity, and act as messengers in the central nervous system. Most eicosanoid receptors are members of the G-protein-coupled receptor superfamily. 

Eicosanoid receptors are G protein-coupled receptors known effector mechanisms include activation or inhibition of adenylate cyclase and activation of phospholipase C. Duration of action is usually short inactivation occurs by oxidative metabolism either locally or in the lung, which is strategically placed for complete clearance of the circulating blood volume. 

Maxey KM. Eicosanoid receptors. The classical receptors. Cayman Currents 1997 5 1-10... 

MECHANISM OF ACTION OF EICOSANOIDS Many of the responses just described can be understood in light of the distribution of eicosanoid receptors and their coupling to second-... 

This table lists the major classes of eicosanoid receptors and dieir signaling characteristics. Splice variants are indicated where appropriate. Major phenotypes in knockout mouse models are listed. 

The eicosanoids have a wide variety of physiologic effects, which are generally initiated through an interaction of the eicosanoid with a specific receptor on the plasma membrane of a target cell (Table 35.4). This eicosanoid-receptor binding either activates the adenylate cyclase-cAMP-protein kinase A system (PGE, PGD,... 

The purpose of the present chapter is to provide an overview of these distinct and complementary roles of the arachidonate cascade, intracellular and transcellular. We will first consider a series of messenger functions that arachidonate metabolites may serve within cells. We will turn next to the transport mechanisms used by the eicosanoids to exit cells and to gain access to transmembrane receptors present on the surface of cells nearby. Finally, we will briefly discuss the molecular structures of the eicosanoid receptors, their transduction mechanisms and some of their physiological and pharmacological properties. 

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