DHA promotes presynaptic terminal maturation and function (804.9)

Abstract

Docosahexaenoic acid (DHA) is an omega‐3 fatty acid enriched in the brain. Several studies have shown that DHA is an essential component for proper brain development and function. Though DHA is implicated to have a strong role in learning and memory, its role in regulating presynaptic function specifically remains unclear. To test if DHA is involved in promoting presynaptic function, we used microfluidic chambers to isolate hippocampal axons and presented them with poly‐lysine‐coated beads to induce presynaptic terminal formation. Both somatodendritic and axonal compartments were treated with either 20μm DHA or Vehicle (DMSO). Presynaptic terminals in DHA‐treated chambers show increased expression of active zone and synaptic vesicle‐associated proteins, Bassoon and Synapsin I compared to controls. In addition, DHA treatment increased synaptic vesicle pool size at the boutons, assessed by using FM dyes. The functional role of DHA in synaptic transmission was tested using FM dye unloading of synaptic vesicles in response to field stimulation. DHA treatment increased the rate of FM dye unloading compared to controls at both 9 days in vitro and 14 days in vitro. These results indicate that in hippocampal neurons, DHA enrichment increases the expression of presynaptic markers, and leads to increased synaptic vesicle pool size and synaptic vesicle release. Together, the data suggest that DHA enhances presynaptic terminal maturation and function.Grant Funding Source: Supported by Mead Johnson Nutrition