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Rat brain docosahexaenoic acid metabolism is not altered by a 6-day intracerebral ventricular infusion of bacterial lipopolysaccharide

2009; Elsevier BV; Volume: 56; Issue: 3 Linguagem: Inglês

10.1016/j.neuint.2009.12.010

1872-9754

Thad A. Rosenberger, Nelly E. Villacreses, Margaret T. Weis, Stanley I. Rapoport,

Peroxisome Proliferator-Activated Receptors

In a rat model of neuroinflammation, produced by a 6-day intracerebral ventricular infusion of bacterial lipopolysaccharide (LPS), we reported that the brain concentrations of non-esterified brain arachidonic acid (AA, 20:4 n-6) and its eicosanoid products PGE2 and PGD2 were increased, as were AA turnover rates in certain brain phospholipids and the activity of AA-selective cytosolic phospholipase A2 (cPLA2). The activity of Ca2+-independent iPLA2, which is thought to be selective for the release of docosahexaenoic acid (DHA, 22:6 n-3) from membrane phospholipid, was unchanged. In the present study, we measured parameters of brain DHA metabolism in comparable artificial cerebrospinal fluid (control) and LPS-infused rats. In contrast to the reported changes in markers of AA metabolism, the brain non-esterified DHA concentration and DHA turnover rates in individual phospholipids were not significantly altered by LPS infusion. The formation rates of AA-CoA and DHA-CoA in a microsomal brain fraction were also unaltered by the LPS infusion. These observations indicate that LPS-treatment upregulates markers of brain AA but not DHA metabolism. All of which are consistent with other evidence that suggest different sets of enzymes regulate AA and DHA recycling within brain phospholipids and that only selective increases in brain AA metabolism occur following a 6-day LPS infusion.