Acute intracerebroventricular administration of palmitoylethanolamide, an endogenous peroxisome proliferator-activated receptor-alpha agonist, modulates carrageenan-induced paw edema in mice.

Abstract

Peroxisome proliferator-activated receptor (PPAR)-alpha is a nuclear transcription factor. Although the presence of this receptor in different areas of central nervous system (CNS) has been reported, its role remains unclear. Palmitoylethanolamide (PEA), a member of the fatty-acid ethanolamide family, acts peripherally as an endogenous PPAR-alpha ligand, exerting analgesic and anti-inflammatory effects. High levels of PEA in the CNS have been found, but the specific function of this lipid remains to be clarified. Using carrageenan-induced paw edema in mice, we show that i.c.v. administration of PEA may control peripheral inflammation through central PPAR-alpha activation. A single i.c.v. administration of 0.01 to 1 microg of PEA, 30 min before carrageenan injection, reduced edema formation in the mouse carrageenan test. This effect was mimicked by 0.01 to 1 microg of GW7647 [2-[[4-[2-[[(cyclohexylamino)carbonyl](4-cyclohexylbutyl)amino]ethyl]phenyl]thio]-2-methylpropanoic acid], a synthetic PPAR-alpha agonist. Moreover, central PEA administration significantly reduced the expression of the proinflammatory enzymes cyclooxygenase-2 and inducible nitric-oxide synthase, and it significantly restored carrageenan-induced PPAR-alpha reduction in the spinal cord. To investigate the mechanism by which i.c.v. PEA attenuated the development of carrageenan-induced paw edema, we evaluated inhibitor kappaB-alpha (I kappa B-alpha) degradation and nuclear factor-kappaB (NF-kappaB) p65 activation in the cytosolic or nuclear extracts from spinal cord tissue. PEA prevented IkB-alpha degradation and NF-kappaB nuclear translocation, confirming the involvement of this transcriptional factor in the control of peripheral inflammation. The obligatory role of PPAR-alpha in mediating the effects of PEA was confirmed by the lack of the compounds anti-inflammatory effects in mutant mice lacking PPAR-alpha. In conclusion, our data show for the first time that PPAR-alpha activation in the CNS can control peripheral inflammation.

• Authors: Giuseppe D'Agostino, Giovanna La Rana, Roberto Russo, Oscar Sasso, Anna Iacono, Emanuela Esposito, Giuseppina Mattace Raso, Salvatore Cuzzocrea, Jesse Lo Verme, Daniele Piomelli, Rosaria Meli, Antonio Calignano
• Journal: The Journal of pharmacology and experimental therapeutics (J Pharmacol Exp Ther) Vol. 322 Issue 3 Pg. 1137-43 (Sep 2007) ISSN: 0022-3565 [Print] United States
• PMID: 17565008 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Amides
• Endocannabinoids
• Ethanolamines
• PPAR alpha
• Palmitic Acids
• palmidrol
• Carrageenan

Topics

• Amides
• Animals
• Carrageenan
• Central Nervous System
• Drug Administration Routes
• Edema (chemically induced, drug therapy)
• Endocannabinoids
• Ethanolamines
• Inflammation (drug therapy)
• Mice
• PPAR alpha (agonists)
• Palmitic Acids (administration & dosage)