In the heart, upon release from the membrane PL in response to hypoxia, the non-esterified HUFA facilitate the synchronization of contraction of cardiac myocytes upon reperfusion by increasing the recovery time of ion channels. A significant body of work in this area has occurred in squamous cell carcinomas of the head and neck over the past 15 years. De très nombreux exemples de phrases traduites contenant "arachidonic acid metabolites" – Dictionnaire français-anglais et moteur de recherche de traductions françaises. We tested the hypothesis that EPA and DHA may compete with arachidonic acid (AA) for the conversion by cytochrome P450 (CYP) enzymes, resulting in the formation of alternative, physiologically active, metabolites. Cellular mechanisms that may be important in the regulation of AA metabolism, where AA metabolites are generated in the intestinal mucosa, and which agents stimulate their formation are discussed. Arachidonic acid is a polyunsaturated, essential fatty acid that has a 20-carbon chain as a backbone and four cis-double bonds at the C5, C8, C11, and C14 positions.It is found in animal and human fat as well as in the liver, brain, and glandular organs, and is a constituent of animal phosphatides. The arachidonic acid metabolites, or eicosanoids, are a large series of lipid-derived mediators capable of producing a multitude of physiologic effects in the local environment. DHA improves neuronal cell survival and differentiation and is involved in neurotransmitter recycling. By slowing the ion channel activity, n – 3 HUFA may also alleviate the symptoms of convulsive seizures, which are characterized by uncontrolled firings of neurons in the central nervous system.Apart from its effects on coronary tone, the actions of AA or cardiac function are unknown. Imbalance between the two arachidonic acid metabolites, prostacyclin (PGI2) and thromboxane A2 (TXA2), is thought to be at least in part responsible for the development of cerebral vasospasm following aneurysm rupture. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) protect against cardiovascular disease by largely unknown mechanisms. Arachidonic acid metabolites formed by both the cyclooxygenase and lipoxygenase pathways may contribute to the diarrhea in inflammatory bowel diseases. This implies that even if a certain PG is active in the heart in a certain respect, administration of AA will mimic this effect only if the specific PG-producing enzyme is present in that part of the heart in which this effect is elicited.n – 3 HUFA prevent cardiac arrhythmia during reperfusion after ischemia.
This review will attempt to familiarize the head and neck surgical oncologist with the basic biochemical steps in the formation of these compounds, newer developments in the field of eicosanoid biochemistry, and related experimental evidence of the roles of these substances in head and neck cancer.N2 - The arachidonic acid metabolites, or eicosanoids, are a large series of lipid-derived mediators capable of producing a multitude of physiologic effects in the local environment.