Do active cerebral neurons really use lactate rather than glucose?
C P Chih1, P Lipton, E L Roberts
1Geriatric Research, Education, and Clinical Center, and Research Office, Miami VA Medical Center, Miami, FL 33125, USA.
Trends in Neurosciences
|September 29, 2001
Summary
Neurons primarily use glucose for energy, not lactate from astrocytes. This challenges the astrocyte-neuron lactate shuttle hypothesis, suggesting glucose remains the main fuel source for brain activity.
Area of Science:
- Neuroscience
- Cellular Metabolism
- Brain Energy
Background:
- The astrocyte-neuron lactate shuttle hypothesis proposes glial cells supply lactate to neurons during high activity.
- This challenges the traditional view of glucose as the primary neuronal energy substrate.
Purpose of the Study:
- To critically evaluate the evidence supporting the astrocyte-neuron lactate shuttle hypothesis.
- To explain neuronal substrate utilization based on enzyme kinetics and substrate availability.
Main Methods:
- Critical examination of existing scientific evidence.
- Analysis from the perspective of enzyme kinetics.
- Assessment of substrate availability in neuronal metabolism.
Main Results:
- Neurons likely utilize ambient glucose as their major energy substrate during activity.
- Evidence supporting glial lactate as the primary neuronal fuel is critically assessed and found wanting.
- Enzyme kinetics and substrate availability favor glucose utilization by neurons.
Conclusions:
- The astrocyte-neuron lactate shuttle hypothesis is not well-supported by current evidence.
- Neurons predominantly rely on glucose, not glial-derived lactate, for energy during heightened activity.
- Understanding brain energy metabolism requires careful consideration of substrate availability and enzyme kinetics.
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