Food and Behaviour Research

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Docosahexaenoic acid promotes neurite growth in hippocampal neurons.

Calderon F, Kim HY. (2004) J Neurochem.  90(4) 979-88. 

Web URL: View this and related abstracts via PubMed here

Abstract:

Docosahexanoic acid (22:6n-3; DHA) deficiency during development is associated with impairment in learning and memory, suggesting an important role of DHA in neuronal development.

Here we provide evidence that DHA promotes neuronal differentiation in rat embryonic hippocampal primary cultures. DHA deficiency in vitro was spontaneously induced by culturing hippocampal cells in chemically defined medium. DHA supplementation improved DHA levels to values observed in freshly isolated hippocampus.

We found that DHA supplementation in culture increased the population of neurons with longer neurite length per neuron and with higher number of branches. However, supplementation with arachidonic, oleic or docosapentaenoic acid did not have any effect, indicating specificity of the DHA action on neurite growth.

Furthermore, hippocampal cultures obtained from n-3 fatty acid deficient animals contained a lower DHA level and a neuronal population with shorter neurite length per neuron in comparison to those obtained from animals with adequate n-3 fatty acids.

DHA supplementation to the deficient group recovered the neurite length to the level similar to n-3 fatty acid adequate cultures. Our data demonstrates that DHA uniquely promotes neurite growth in hippocampal neurons. Inadequate neurite development due to DHA deficiency may contribute to the cognitive impairment associated with n-3 fatty acid deficiency.

FAB RESEARCH COMMENT:

In this study, the growth and connectivity of brain cells in regions known to support memory (and other aspects of cognition) was shown to depend critically on the availability of the long-chain omega-3 DHA.

Dietary deprivation of DHA was found to reduce both the number and length of projections these brain cells showed (indicating reduced communication with other cells and processes), while supplementation with DHA increased them.

The experiments involved studying rats raised on different diets, and comparing the growth of their brain cells both naturally, and when cultured 'in vitro' (i.e. in 'test-tube' or 'laboratory dish' conditions) with and without DHA.

While findings from animal or in vitro studies can never be assumed to generalise to humans, these findings are consistent with other evidence for the crucial importance of long-chain omega-3 DHA for normal brain development and cognitive function.