Lactate-mediated glia-neuronal signalling in the mammalian brain.
Level 5 - mechanism / opinion, no new human data
Preclinical in vitro and in vivo animal/cellular study with no human data.
PubMed 24518663 · doi:10.1038/ncomms4284
What was done
Investigated the signaling effects of astrocytic L-lactate in the locus coeruleus using optogenetic activation of astrocytes, application of exogenous L-lactate, and in vivo microinjections into the mammalian locus coeruleus.
What was found
Optogenetically activated astrocytes released L-lactate, which excited locus coeruleus neurons and triggered norepinephrine release. Exogenous L-lactate produced equivalent concentration-dependent, stereo-selective effects that did not depend on neuronal uptake and involved a cAMP-mediated mechanism. In vivo locus coeruleus injections of L-lactate evoked arousal comparable to L-glutamate. The abstract reports no exact numerical values, sample sizes, or test statistics.
Why it matters
Demonstrates that L-lactate can function directly as an active glio-transmitter modulating locus coeruleus activity and arousal, rather than solely serving as a passive metabolic fuel for neurons.
Limits
The abstract provides no sample sizes, animal model species specifications, or quantitative effect sizes. The proposed receptor mediating L-lactate signaling was not identified, and preclinical animal findings cannot be directly assumed to operate identically in humans.
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