In: Biology
Is fatty acid an effective energy source in the central nervous system?
Answer: No, fatty acid is not an effective energy source in the central nervous system.
(1) ATP generation linked to -oxidation of
fatty acids demands more oxygen than glucose, thereby enhancing the
risk for neurons to become hypoxic
(2) -oxidation of
fatty acids generates superoxide, which, taken together with the
poor anti-oxidative defense in neurons, causes severe oxidative
stress
(3) the rate of ATP generation based on adipose tissue-derived fatty acids is slower than that using blood glucose as fuel.
Thus, in periods of extended continuous and rapid neuronal firing, fatty acid oxidation cannot guarantee rapid ATP generation in neurons.
We conjecture that the disadvantages connected with using fatty
acids as fuel have created evolutionary pressure on lowering the
expression of the -oxidation enzyme
equipment in brain mitochondria to avoid extensive fatty acid
oxidation and to favor glucose oxidation in brain.