Prostaglandin E

Sanders Did you ever look to see whether indomethacin (i.e. prostaglandin inhibition) decreases coupling between these Ca2+ waves and activation of BK channels Perhaps this is your time delay. Production of prostaglandin should activate protein kinase A because of cAMP production, and this will increase BK open probability. 

The autacoids comprise histamine, serotonin, angiotensin, neurotensin, NO (nitric oxide), kinins, platelet-activating factor, endothelins and the four families of traditional eicosanoids - the leukotrienes and three types of prostanoids i.e. prostaglandins, prostacyclins, and thromboxanes. Several other natural occurring molecules are sometimes called eicos-anoid, including the hepoxilins, resolvins, isofurans, isoprostanes, lipoxins, epoxyeicosatrienoic acids (EETs) and some endocannabinoids. However, not... 

Correct answer = E. Prostaglandins are synthesized from arachidonic acid. Arachidonic acid is synthesized from linoleic acid, an essential fatty acid obtained by humans from dietary lipids. The teenager would be able to synthesize all other compounds, but presumably in somewhat depressed amounts. 

Prostaglandins have been implicated both in the induction of inflammation and in its relief. In inflammation small blood vessels become dilated, and fluid and proteins leak into the interstitial spaces to produce the characteristic swelling (edema). Many polymorphonuclear leukocytes attracted by chemotactic factors that include LTB4309 (Chapter 19) migrate into the inflamed area, engulfing dead tissue and bacteria. In this process lysosomes of the leukocytes release phospholipase A, which hydrolyzes phospholipids and initiates the arachidonate cascade. The leukotrienes that are formed promote the inflammatory response. However, cAMP can suppress inflammation, and PGE2 has a similar effect. Indeed, E prostaglandins, when inhaled in small amounts, relieve asthma. 

Collier HO, Roy AC. Morphine-like drugs inhibit the stimulation of E prostaglandins of cyclic AMP formation by rat brain homogenate. Nature 1974 248 24-27. 

EUmimtion of iodohydrins. Treatment of the iodolactone (1) in dry pyridine with 1.3 eq. of mesyl chloride at -20° for 2 hr. and at 0° for 1.5 hr. affords the unsaturated lactone (2) in practically quantitative yield. The reaction provided a key step in the synthesis of A prostaglandins, which previously were available from the primary E prostaglandins by dehydration of the )S-kctol unit. 

Conversion of F into E prostaglandins. Yankee and Bundy have reported that I5-methyl-PGH2, methyl ester (I) can be. silylated preferentially at the 11-position... 

This method has now been shown to be general for conversion of F into E prostaglandins. Thus the methyl ester of PGF2, (4) on treatment with TSiD is disilylatcd at... 

Specific reduction of E prostaglandins to F, prostaglandins. One useful reaction in prostaglandin research is the interconversion of primary1 prostaglandins, for example, reduction of prostaglandin E2 (1) to prostaglandin F2a (2). Reduction of(l) with sodium... 

Prostaglandins - Several reports indicate that the products of arachi-donic acid metabolism, i.e., prostaglandins, prostacyclins and thromboxanes are involved in the pathophysiology of obstructive lung disease.Prostaglandins of the E series are bronchodilators while prostaglandins of the F series are bronchoconstrictors. 

Besides histamine release, mast cell degranulation releases interleukins, proteases, and other enzymes that activate the production of other mediators of inflammation. Several classes of important mediators, including arachidonic acid and its metaholites (i.e., prostaglandins, leukotrienes, and platelet-activating factor), are derived from cell membrane phospholipids. 

EYE Although PGE induces constriction of the iris sphincter muscle, its overall effect in the eye is to decrease intraocular pressure by increasing the aqueous humor outflow of the eye via the uveoscleral and trabecular meshwork pathway. A variety of E prostaglandin-receptor agonists have proven effective in the treatment of open-angle glaucoma, a condition associated with the loss of COX-2 expression in the pigmented epithelium of the cfliary body (see Chapter 63). 

The previously reported alkene 335 (from L-glucose, vol. 28, p. 373) has now been elaborated to l2-e/ /-prostaglandin F2a- The C35-C43 subunit of dolastatin G (336) has been prepared from levoglucosenone. ... 

---