Keywords: exergy analysis, neurons, astrocyte, brain energy metabolism, exergetic efficiency, ATP production, neuronal glucose metabolism, adenosine triphosphate, modelling, lactate shuttle model, aerobic respiration, thermodynamics, pyruvate production, cytoplasm
Exergetic efficiency of ATP production in neuronal glucose metabolism
The exergetic efficiency of ATP production in the brain is assessed using two competing models: 1) the classical model, where both neuron and the astrocyte metabolise glucose; 2) the astrocyte–neuron lactate shuttle hypothesis (ANLSH), where astrocytes metabolise glucose to lactate, then shuttle it to the neuron for aerobic respiration. Exergy analyses showed that ATP production in neuronal mitochondrion is thermodynamically much more efficient than in the cytoplasm. Comparing the Cumulative Degree of Perfection (CDP) for pyruvate production under both models showed that pyruvate production in the cytoplasm causes less exergy loss when lactate is the energy source. Therefore, we predict that the lactate shuttle model is energetically more favourable to the neuron.