Arachidonic Acid and Docosahexaenoic Acid-derived Lipid Mediators in Brain

Docosahexaenoic acid and arachidonic acid are major polyunsaturated fatty acids in neural membrane glycerophospholipids. Docosahexaenoic acid and arachidonic acid are metabolically and functionally distinct molecules that have opposing physiological functions. Docosahexaenoic acid is metabolized to docosanoids, whereas arachidonic acid is metabolized to eicosanoids. Like their precursors, docosanoids and eicosanoids are different types of lipid mediators, which play important and opposing roles in modulating inflammatory reactions, oxidative stress, neuroprotection, and neurodegeneration. Increase in levels of eicosanoids occurs in acute neural trauma (stroke and traumatic injury to brain and spinal cord) and neurodegenerative diseases (Alzheimer disease, Parkinson disease, and Huntington disease), whereas consumption of DHA increases levels of docosanoids, which have antioxidant, anti-inflammatory, and anti-apoptotic properties. Synthesis of docosanoids is an endogenous neuroprotective mechanism against acute neural trauma and neurodegenerative diseases.

Keywords: Arachidonic acid; docosahexaenoic acid; eicosanoids; docosanoids; eicosapentaenoic acid; oxidative stress; inflammation; apoptosis; neurodegenerative diseases