AA and Parkinson's Disease.

Parkinson's disease (PD) is due to degeneration of dopaminergic neurons in substantia nigra pars compacta. PD neuropathology is characterized by the presence of Lewy bodies that contain aggregated α-synuclein, which has been implicated in a range of interactions with phospholipid membranes and free fatty acids. I propose that α-synuclein interacts with arachidonic acid (AA) to regulate the function of dopaminergic neurons. α-Synuclein sequesters AA, whereas AA induces the formation of oligomers that are alpha-helical; resistant to fibril formation; more prone to disaggregation, enzymatic digestion, and degradation; and hence less likely to cause neuronal damage and induce PD. In addition, AA interacts with syntaxin to regulate exocytosis of various neurotransmitters, including dopamine. AA has potent anti-inflammatory actions, serves as a mechanotransducer, influences cell membrane fluidity, enhances glucose uptake by neurons, possesses cytoprotective action, and is the precursor of anti-inflammatory lipoxin A4 (LXA4), actions that maintain the integrity of dopaminergic neurons in the substantia nigra pars compacta. The dynamic equilibrium among α-synuclein, syntaxin, AA, exocytosis of dopamine, formation of LXA4, and the inflammatory process is involved in the development of PD. This implies that deficiency of AA can render dopaminergic neurons susceptible to inflammatory neurodegeneration and development of PD. Hence, it is proposed that administration of AA and DHA (that are present in substantial amounts in the brain) can be used in the prevention and management of PD.