Learning-Induced Gene Expression in the Hippocampus Reveals a Role of Neuron -Astrocyte Metabolic Coupling in Long Term Memory

PLoS One. 2015 Oct 29;10(10):e0141568. doi: 10.1371/journal.pone.0141568. eCollection 2015.

Abstract

We examined the expression of genes related to brain energy metabolism and particularly those encoding glia (astrocyte)-specific functions in the dorsal hippocampus subsequent to learning. Context-dependent avoidance behavior was tested in mice using the step-through Inhibitory Avoidance (IA) paradigm. Animals were sacrificed 3, 9, 24, or 72 hours after training or 3 hours after retention testing. The quantitative determination of mRNA levels revealed learning-induced changes in the expression of genes thought to be involved in astrocyte-neuron metabolic coupling in a time dependent manner. Twenty four hours following IA training, an enhanced gene expression was seen, particularly for genes encoding monocarboxylate transporters 1 and 4 (MCT1, MCT4), alpha2 subunit of the Na/K-ATPase and glucose transporter type 1. To assess the functional role for one of these genes in learning, we studied MCT1 deficient mice and found that they exhibit impaired memory in the inhibitory avoidance task. Together, these observations indicate that neuron-glia metabolic coupling undergoes metabolic adaptations following learning as indicated by the change in expression of key metabolic genes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Astrocytes / metabolism*
  • Astrocytes / physiology
  • Avoidance Learning*
  • Glucose Transporter Type 1 / genetics
  • Glucose Transporter Type 1 / metabolism
  • Hippocampus / cytology
  • Hippocampus / metabolism*
  • Hippocampus / physiology
  • Male
  • Memory, Long-Term*
  • Mice
  • Mice, Inbred C57BL
  • Monocarboxylic Acid Transporters / genetics
  • Monocarboxylic Acid Transporters / metabolism
  • Neurons / metabolism*
  • Neurons / physiology
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism*
  • Sodium-Potassium-Exchanging ATPase / genetics
  • Sodium-Potassium-Exchanging ATPase / metabolism

Substances

  • Glucose Transporter Type 1
  • Monocarboxylic Acid Transporters
  • RNA, Messenger
  • Sodium-Potassium-Exchanging ATPase

Grants and funding

This work was supported by FNRS grant 31003A-130821/1 and 310030B-148169/1, by the National Center of Competence in Research (NCCR) “SYNAPSY” (n° 51AU40-125759) and by the Panacée and Biaggi Foundations. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.