Metabolic substrates other than glucose support axon function in central white matter

AM Brown, R Wender… - Journal of neuroscience …, 2001 - Wiley Online Library
AM Brown, R Wender, BR Ransom
Journal of neuroscience research, 2001Wiley Online Library
We tested the hypothesis that non‐glucose energy sources can support axon function in the
rat optic nerve. Axon function was assessed by monitoring the stimulus‐evoked compound
action potential (CAP). CAP was maintained at full amplitude for 2 hr in 10 mM glucose. 20
mM lactate, 20 mM pyruvate, 10 mM fructose, or 10 mM mannose supported axon function
as effectively as did glucose, and 10 mM glutamine provided partial support, but β‐
hydroxybutyrate, octanoate, sorbitol, alanine, aspartate, and glutamate failed to support …
Abstract
We tested the hypothesis that non‐glucose energy sources can support axon function in the rat optic nerve. Axon function was assessed by monitoring the stimulus‐evoked compound action potential (CAP). CAP was maintained at full amplitude for 2 hr in 10 mM glucose. 20 mM lactate, 20 mM pyruvate, 10 mM fructose, or 10 mM mannose supported axon function as effectively as did glucose, and 10 mM glutamine provided partial support, but β‐hydroxybutyrate, octanoate, sorbitol, alanine, aspartate, and glutamate failed to support axon function. Our results indicated that a variety of compounds can sustain function in CNS myelinated axons. Axons probably use lactate, pyruvate, and glutamine directly as energy substrates, whereas mannose and fructose could be shuttled through astrocytes to lactate, which is then exported to axons. © 2001 Wiley‐Liss, Inc.
Wiley Online Library