8-isoprostaglandin-e2 and anandamide

It is widely accepted that neuroinflammation is a key player in various pathological events associated with brain injury. More specifically, glial activation and the subsequent release of pro-inflammatory cytokines, reactive oxygen species (ROS), and prostaglandins play a role of paramount importance in cerebral damage. In this study, we examined the role of two endocannabinoids, anandamide (AEA) and N-arachidonoyldopamine (NADA) in the regulation of prostaglandin E(2) (PGE(2)) synthesis in primary glial cells. We show that NADA is a potent inhibitor of PGE(2) synthesis in lipopolysaccharide (LPS) stimulated cells, without modifying the expression or enzymatic activity of COX-2 and the production of prostaglandin D(2). We also show that NADA has the ability to prevent the free radical formation in primary microglial cells. The key findings of this investigation are our observation that AEA and NADA have opposite effects on glial cells and, most importantly, the first description of NADA as a potential antioxidative and anti-inflammatory agent acting through a mechanism that involves reduction in the synthesis of microsomal prostaglandin E synthase in LPS-activated microglia. These findings provide new mechanistic insights into the anti-inflammatory activities of NADA in the CNS and its potential to design novel therapeutic strategies to manage neuroinflammatory diseases.

Topics: Animals; Animals, Newborn; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Arachidonic Acids; Cell Survival; Dinoprostone; Dopamine; Endocannabinoids; Isomerism; Isoprostanes; Mice; Mice, Inbred C57BL; Mice, Knockout; Neuroglia; Polyunsaturated Alkamides; Rats; Rats, Sprague-Dawley

1. Cumulative concentration-effect curves for the selective prostanoid TP receptor agonist U46619 and six isoprostanes were constructed in the human isolated umbilical artery. 2. All compounds except 8-iso-PGF3 alpha produced concentration-dependent contractions. The contractile response to the isoprostanes increased with each cumulative addition up to a point, after which subsequent addition reduced the contraction below the previous level. This 'downturn' in the concentration-effect curve did not occur with U46619. 3. The potencies of the compounds tested were as follows (pEC50 +/- s.e.mean): U46619, 6.7 +/- 0.2; 8-iso-PGE2, 6.5 +/- 0.1; 8-iso-PGF2 alpha, 5.8 +/- 0.2; 8-iso-PGE1, 5.4 +/- 0.1; 8-iso-PGF1 alpha, 5.0 +/- 0.1; 8-iso-PGF2 beta > 4.8; 8-iso-PGF3 alpha >> 4.8 (n = 4-17). Neither 8-iso-PGF2 beta nor 8-iso-PGF3 alpha at 44 microM had a significant effect on cumulative concentration-effect curves to U46619. 4. The selective TP receptor antagonist GR32191 (0.1 microM) caused rightward shifts in the concentration-effect curves to all the active compounds. pA2 values for GR32191 against U46619, 8-iso-PGE2, 8-iso-PGF2 alpha, 8-iso-PGE1 were 7.6 +/- 0.2, 9 +/- 1, 8.2 +/- 0.3 and 7.7 +/- 0.3, respectively (n = 4). 5. Neither N omega-nitro-L-arginine methyl ester (100 microM) nor the selective DP receptor antagonist BW A868C (50 nM) affected the complex concentration-effect curve to 8-iso-PGE2 (n = 3). 6. Stable contractions to U46619 (1-3 microM) were unaffected by anandamide at concentrations up to 60 microM.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Arachidonic Acids; Dinoprostone; Endocannabinoids; Enzyme Inhibitors; Female; Humans; Hydantoins; In Vitro Techniques; Isometric Contraction; Isoprostanes; Muscle Contraction; NG-Nitroarginine Methyl Ester; Polyunsaturated Alkamides; Pregnancy; Prostaglandins F; Prostaglandins, Synthetic; Receptors, Prostaglandin; Structure-Activity Relationship; Umbilical Arteries