Arachidonic acid enhances intracellular calcium levels in dentate gyrus, but not CA1, in aged rat

PUFA and their derivatives in neurotransmission and synapses: a new hallmark of synaptopathies

PUFA of the n-3 and n-6 families are present in high concentration in the brain where they are major components of cell membranes. The main forms found in the brain are DHA (22 :6, n-3) and arachidonic acid (20:4, n-6). In the past century, several studies pinpointed that modifications of n-3 and n-6 PUFA levels in the brain through dietary supply or genetic means are linked to the alterations of synaptic function. Yet, synaptopathies emerge as a common characteristic of neurodevelopmental disorders, neuropsychiatric diseases and some neurodegenerative diseases. Understanding the mechanisms of action underlying the activity of PUFA at the level of synapses is thus of high interest. In this frame, dietary supplementation in PUFA aiming at restoring or promoting the optimal function of synapses appears as a promising strategy to treat synaptopathies. This paper reviews the link between dietary PUFA, synapse formation and the role of PUFA and their metabolites in synaptic functions.

Lymnaea stagnalis as model for translational neuroscience research: From pond to bench

The purpose of this review is to illustrate how a reductionistic, but sophisticated, approach based on the use of a simple model system such as the pond snail Lymnaea stagnalis (L. stagnalis), might be useful to address fundamental questions in learning and memory. L. stagnalis, as a model, provides an interesting platform to investigate the dialog between the synapse and the nucleus and vice versa during memory and learning. More importantly, the "molecular actors" of the memory dialogue are well-conserved both across phylogenetic groups and learning paradigms, involving single- or multi-trials, aversion or reward, operant or classical conditioning. At the same time, this model could help to study how, where and when the memory dialog is impaired in stressful conditions and during aging and neurodegeneration in humans and thus offers new insights and targets in order to develop innovative therapies and technology for the treatment of a range of neurological and neurodegenerative disorders.

Arachidonic acid-enriched triacylglycerol improves cognitive function in elderly with low serum levels of arachidonic acid

Arachidonic acid (ARA) is an n-6 PUFA and is thought to have an important role in various physiological and psychological functions. Recently, supplementation with ARA-enriched TAG was shown to improve age-related decreases in cognitive function in healthy elderly men. To investigate the influence of baseline serum ARA status on cognitive function and its improvement, we analyzed cognitive function stratified by serum ARA level. The stratified analysis was also conducted for the effects of ARA-enriched TAG supplementation on cognitive improvement. Cognitive function was evaluated by measuring event-related potentials (ERPs), including P300 latency and amplitude. When participants were stratified by baseline serum ARA level, P300 latency was significantly longer and P300 amplitude was generally lower in the low-ARA group than in the high-ARA group. No significant difference in P300 components was observed when participants were stratified by serum levels of any other fatty acid. ARA-enriched TAG supplementation significantly shortened P300 latency and increased P300 amplitude in the low-ARA group, although no significant differences were observed in the high-ARA group. These findings suggest that lower serum ARA levels were associated with cognitive function in elderly men and that ARA-enriched TAG supplementation is more effective in improving cognitive function in healthy elderly men with low serum ARA levels than in those with high serum ARA levels.

n-3 fatty acids prevent impairment of neurogenesis and synaptic plasticity in B-cell activating factor (BAFF) transgenic mice

OBJECTIVE

Autoimmune-prone B-cell activating factor transgenic mice, a mouse model of systemic lupus erythematosus and Sjögren's syndrome exhibit neuroinflammation, anxiety-like phenotype, deficit in adult hippocampal neurogenesis and impaired neurogenesis-dependent and neurogenesis-independent dentate gyrus long-term potentiation. Given that n-3 polyunsaturated fatty acids regulate hippocampal plasticity and inflammatory responses, we investigated whether n-3 polyunsaturated fatty acids-enriched diet might prevent age-dependent hippocampal changes in B-cell activating factor transgenic mice.

METHODS

B-cell activating factor transgenic mice were fed for 12 weeks with either n-3 polyunsaturated fatty acids-enriched or control diet and we tested the effect of this dietary supplementation on hippocampal inflammation, progenitor cell proliferation and neurogenesis-dependent and neurogenesis-independent long-term potentiation.

RESULTS

Dietary supplementation with n-3 polyunsaturated fatty acids significantly decreased hippocampal microglial activation and increased the density of bromodeoxyuridine and doublecortin-positive newly-formed cells in the subventricular zone of hippocampus. Furthermore, B-cell activating factor transgenic mice fed with n-3 polyunsaturated fatty acids-enriched diet displayed normal long-term potentiation at the medial perforant pathway/dentate gyrus connections.

CONCLUSIONS

The results indicate that n-3 fatty acids prevent neuroinflammation and deficits of hippocampal plasticity in B-cell activating factor transgenic mice and suggest that increased n-3 fatty acids intake might represent a potential therapeutic option to prevent neuropsychiatric symptoms associated with autoimmune diseases.