
Transient metabolic failure can lead to a duration-dependent bidirectional dysregulation of glutamate release and synaptic transmission, with short durations potentiating glutamate release and longer durations inducing postsynaptic failure.


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Ischemia leads to a severe dysregulation of glutamate homeostasis and excitotoxic cell damage in the brain. Shorter episodes of energy depletion, for instance during peri-infarct depolarizations, can also acutely perturb glutamate signaling. It is less clear if such episodes of metabolic failure also have persistent effects on glutamate signaling and how the relevant mechanisms such as glutamate release and uptake are differentially affected. We modelled acute and transient metabolic failure by using a chemical ischemia protocol and analyzed its effect on glutamatergic synaptic transmission and extracellular glutamate signals by electrophysiology and multiphoton imaging, respectively, in the hippocampus. Our experiments uncover a duration-dependent bidirectional dysregulation of glutamate signaling. Whereas short chemical ischemia induces a lasting potentiation of presynaptic glutamate release and synaptic transmission, longer episodes result in a persistent postsynaptic failure of synaptic transmission. We also observed an unexpected hierarchy of vulnerability of the involved mechanisms and cell types. Axonal action potential firing and glutamate uptake were unexpectedly resilient compared to postsynaptic cells, which overall were most vulnerable to acute and transient metabolic stress. We conclude that even short perturbations of energy supply lead to a lasting potentiation of synaptic glutamate release, which may increase glutamate excitotoxicity well beyond the metabolic incident.

### Competing Interest Statement

The authors have declared no competing interest.

Bidirectional dysregulation of synaptic glutamate signaling after transient metabolic failure

transient-metabolic-failure-leads-to-bidirectional-dysregulation-of-synaptic-glutamate-signaling


Transient Metabolic Failure Leads to Bidirectional Dysregulation of Synaptic Glutamate Signaling
