Albifylline is a xanthine derivates with anti-asthmatic activity. Albifylline may cause a significant reduction of shock-induced leukocyte adhesions to the sinusoidal endothelium in the liver after hemorrhagic shock. Albifylline also improves microvascula
Arachidonic acid is metabolized in the vascular endothelium to epoxytrienoic acids (EETs or EpETrEs) by cytochrome P450 enzymes. The EETs are released in response to acetylcholine, bradykinin, arachidonic acid, or cyclic stretch. (±)14(15)-EET-SI is the methyl sulfonamide analog of 14(15)-EET. This substitution results in a metabolically more stable compound because it is not sensitive to β-oxidation or membrane esterification. (±)14(15)-EET-SI is equipotent to 14(15)-EET in vascular agonist activity as measured by relaxation of precontracted bovine coronary arteries. In addition, 14(15)-EET and the methyl sulfonamide analog both stimulate tyrosine phosphorylation and induce mitogenesis in renal epithelial cells.
Neuromedin U (NMU) is a neuropeptide first demonstrated to drive smooth muscle contraction.1Translated as a 174 amino acid propeptide, NMU is cleaved to different lengths in different animals. It has diverse receptor-mediated rolesin vivo, as it regulates feeding, vasoconstriction, nociception, and bone remodeling and contributes to obesity, cancer and septic shock.2,2NMU-25 is the active form of NMU in humans. It binds with high affinity to receptors on human left ventricle and coronary artery (KDs = 0.26 and 0.11 nM, respectively), eliciting endothelium-independent vasoconstriction.3NMU-25 also suppresses glucose-stimulated insulin secretion in human islets, and this effect is lost in NMU R165W mutants, resulting in early-onset obesity.4 1.Mitchell, J.D., Maguire, J.J., and Davenport, A.P.Emerging pharmacology and physiology of neuromedin U and the structurally related peptide neuromedin SBritish Journal of Pharmacology15887-103(2009) 2.Greenwood, H.C., Bloom, S.R., and Murphy, K.G.Peptides and their potential role in the treatment of diabetes and obesityRev.Diabet.Stud.8(3)355-368(2011) 3.Mitchell, J.D., Maguire, J.J., Kuc, R.E., et al.Expression and vasoconstrictor function of anorexigenic peptides neuromedin U-25 and S in the human cardiovascular systemCardiovascular Research81353-361(2009) 4.Alfa, R.W., Park, S., Skelly, K.R., et al.Suppression of insulin production and secretion by a decretin hormoneCell Metabolism21(2)323-333(2015)
Angiotensin II is a hormone that plays an important role in regulating blood pressure. Elevated levels of angiotensin II are implicated in inducing and maintaining hypertension, and also in the development of atherosclerosis. Both of these effects are mediated by the angiotensin II type 1 (AT1) receptor. Losartan is a mammalian AT1 receptor antagonist with a Ki value of 5-20 nM. In humans, losartan effectively controls hypertension while protecting renal function. Nitric oxide (NO) causes vasodilation and also inhibits platelet and neutrophil aggregation in the endothelium. NO-losartan A possesses similar anti-hypertensive effects to losartan, with the addition of the vasodilating effects of NO release.
Cytochrome P450 metabolites of arachidonic acid, such as 11(12)-EpETrE and 14(15)-EpETrE have been identified as endothelium derived hyperpolarizing factors with vasodilator activity. Soluble epoxide hydrolase (sEH) catalyzes the conversion of EpETrEs to the corresponding DiHETrEs thereby diminishing their activity. Inhibitors of sEH may therefore have clinical utility for treating hypertension and systemic inflammation. S-NEPC is a colorimetric substrate used to measure sEH activity. It also is a substrate for Glutathione S-transferase, microsomal epoxide hydrolase and porcine liver carboxylesterase. Hydrolysis of S-NEPC by sEH yields 4-nitrophenol which can be quantified spectrophotometrically at 405 nm. S-NEPC is adaptable for use in 96-well microwell plate readers.
Epoxyeicosatrienoic acids (EETs), such as 11(12)-EET and 14(15)-EET, are cytochrome P450 metabolites of arachidonic acid that have been identified as endothelium-derived hyperpolarizing factors with vasodilator activity. 14,15-EE-5(Z)-E is a structural analog of 14,15-epoxyeicosatrienoic acids (14,15-EET) that antagonizes EET-induced relaxation of vascular smooth muscle. Relaxation of U46619-constricted bovine arteries by 14,15-EET could be inhibited approximately 80% by 14,15-EE-5(Z)-E at a concentration of 10 μM. 14,15-EE-5(Z)-E does not appear to antagonize nitric oxide- or iloprost-mediated vascular relaxation.
Epoxyeicosatrienoic acids (EETs), such as 11(12)-EET and 14(15)-EET, are cytochrome P450 metabolites of arachidonic acid that have been identified as endothelium-derived hyperpolarizing factors with vasodilator activity. 14,15-EE-8(Z)-E is a structural analog of 14(15)-EET that demonstrates potent vasodilator agonist activity in bovine coronary arteries similar to that of 14(15)-EET.
EDHF (endothelium-derived hyperpolarizing factor) is an unidentified mediator released from vascular endothelial cells in response to acetylcholine and bradykinin which is distinct from the NOS- (nitric oxide) and COX-derived (prostacyclin) vasodilators.[1],[2]Cytochrome P450 (CYP450) metabolism of polyunsaturated fatty acids produces epoxides such as (±)14(15)-EET which are prime candidates for the actual active mediator.[3] However, the CYP450 metabolites of eicosapentaenoic acid and docosahexaenoic acid have been little studied relative to arachidonate epoxygenase metabolites. (±)16(17)-EpDPA is the DHA homolog of (±)14(15)-EpETrE, derived via epoxidation of the 16,17-double bond of DHA. The EDHF activity of (±)16(17)-EpDPA has not yet been determined. The epoxygenase metabolites of DHA have also been detected in a mouse inflammation model.[4]