Oligodendrocytes make myelin and support axons metabolically with lactate. However, it is unknown how glucose utilization and glycolysis are adapted to the different axonal energy demands. Spiking axons release glutamate and oligodendrocytes express NMDA receptors of unknown function. Here we show that the stimulation of oligodendroglial NMDA receptors mobilizes glucose transporter GLUT1, leading to its incorporation into the myelin compartment in vivo. When myelinated optic nerves from conditional NMDA receptor mutants are challenged with transient oxygen-glucose deprivation, they show a reduced functional recovery when returned to oxygen-glucose but are indistinguishable from wild-type when provided with oxygen-lactate. Moreover, the functional integrity of isolated optic nerves, which are electrically silent, is extended by preincubation with NMDA, mimicking axonal activity, and shortened by NMDA receptor blockers. This reveals a novel aspect of neuronal energy metabolism in which activity-dependent glutamate release enhances oligodendroglial glucose uptake and glycolytic support of fast spiking axons.
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http://dx.doi.org/10.1016/j.neuron.2016.05.016 | DOI Listing |
The transmembrane protein Synapse Differentiation Induced Gene 4 (SynDIG4) functions as an auxiliary factor of AMPA receptors (AMPARs) and plays a critical role in excitatory synapse plasticity as well as hippocampal-dependent learning and memory. Mice lacking SynDIG4 have reduced surface expression of GluA1 and GluA2 and are impaired in single tetanus-induced long-term potentiation and NMDA receptor (NMDAR)-dependent long-term depression. These findings suggest that SynDIG4 may play an important role in regulating AMPAR distribution through intracellular trafficking mechanisms; however, the precise roles by which SynDIG4 governs AMPAR distribution remain unclear.
View Article and Find Full Text PDFIt is well known that activation of NMDA receptors can trigger long-term synaptic depression (LTD) and that a morphological correlate of this functional plasticity is spine retraction and elimination. Recent studies have led to the surprising conclusion that NMDA-induced spine shrinkage proceeds independently of ion flux and requires the initiation of protein synthesis, highlighting an unappreciated contribution of mRNA translation to non-ionotropic NMDAR signaling. Here we used NMDA-induced spine shrinkage in slices of mouse hippocampus as a readout to investigate this novel modality of synaptic transmission.
View Article and Find Full Text PDFUnlabelled: Pain therapies that alleviate both pain and sleep disturbances may be the most effective for pain relief, as both chronic pain and sleep loss render the opioidergic system, targeted by opioids, less sensitive and effective for analgesia. Therefore, we first studied the link between sleep disturbances and the activation of nociceptors in two acute pain models. Activation of nociceptors in both acute inflammatory (AIP) and opto-pain models led to sleep loss, decreased sleep spindle density, and increased sleep fragmentation that lasted 3 to 6 hours.
View Article and Find Full Text PDFHumans exhibit unique cognitive abilities within the animal kingdom, but the neural mechanisms driving these advanced capabilities remain poorly understood. Human cortical neurons differ from those of other species, such as rodents, in both their morphological and physiological characteristics. Could the distinct properties of human cortical neurons help explain the superior cognitive capabilities of humans? Understanding this relationship requires a metric to quantify how neuronal properties contribute to the functional complexity of single neurons, yet no such standardized measure currently exists.
View Article and Find Full Text PDFNeurogenetics
January 2025
Department of Biochemistry, College of Medicine, University of Lagos, Lagos State, Nigeria.
Schizophrenia (SZ) is a complex, chronic mental disorder characterized by positive symptoms (such as delusions and hallucinations), negative symptoms (including anhedonia, alogia, avolition, and social withdrawal), and cognitive deficits (affecting attention, processing speed, verbal and visuospatial learning, problem-solving, working memory, and mental flexibility). Extensive animal and clinical studies have emphasized the NMDAR hypofunction hypothesis of SZ. Glycine plays a crucial role as an agonist of NMDAR, enhancing the receptor's affinity for glutamate and supporting normal synaptic function and plasticity, that is, signal transmission between neurons.
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