The profile of fatty acids in frontal cortex of rats depends on the type of fat used in the diet and correlates with neuropeptidase activities.

The kind of fat in the diet modifies the profile of fatty acids in brain and also affects aminopeptidase activities in tissues. Although modifications in brain fatty acids, neurotransmitters, or enzymes due to dietary fat composition have been reported, no direct relationship has yet been described between specific brain fatty acid changes and neuropeptide metabolism following the fat composition of the diet. We investigated the lipid profile and some neuropeptidase activities in the frontal cortex of adult male rats after a period in which diets were supplemented with fatty acids differing in their degrees of saturation such as fish oil (rich in polyunsaturated fatty acids, PUFAs), olive oil (rich in monounsaturated fatty acids, MUFAs), and coconut oil (rich in saturated fatty acids, SAFAs). It is observed that the diet composition affects fatty acid distribution in the brain. Although there is no change of global aminopeptidase/neuropeptidase, their activities in the brain correlate positively or negatively with the dietary fat composition. It is hypothesized that fatty acid in the diet modifies membrane fluidity, peptidases tertiary structure, and therefore, the availability and function of neuropeptides. The present results support the notion that cognitive functions may be modulated depending on the type of fat used in the diet.