Title: Exergetic efficiency of ATP production in neuronal glucose metabolism

Authors: Seda Genc; Esra Sorguven; Isıl Aksan Kurnaz; Mustafa Ozilgen

Addresses: Department of Chemical Engineering, Yeditepe University, Istanbul 34755, Turkey ' Department of Mechanical Engineering, Yeditepe University, Istanbul 34755, Turkey ' Department of Genetics and Bioengineering, Yeditepe University, Istanbul 34755, Turkey ' Department of Food Engineering, Yeditepe University, Istanbul 34755, Turkey

Abstract: 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.

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.

DOI: 10.1504/IJEX.2013.055778

International Journal of Exergy, 2013 Vol.13 No.1, pp.60 - 84

Received: 24 Jul 2012
Accepted: 30 Aug 2012
Published online: 08 Aug 2013 *

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