Astrocytic Mechanisms Explaining Neural-Activity-Induced Shrinkage of Extraneuronal Space
Author Information
Author(s): Østby Ivar, Øyehaug Leiv, Einevoll Gaute T., Nagelhus Erlend A., Plahte Erik, Zeuthen Thomas, Lloyd Catherine M., Ottersen Ole P., Omholt Stig W.
Primary Institution: Norwegian University of Life Sciences
Hypothesis
What mechanisms underlie the shrinkage of the extracellular space (ECS) observed during neuronal activation?
Conclusion
The study presents a mathematical model that explains ECS shrinkage during neuronal activity as a result of potassium and sodium transport processes in astrocytes.
Supporting Evidence
- Neuronal stimulation causes approximately 30% shrinkage of the extracellular space.
- The model accounts for potassium and sodium transport during neuronal activation.
- Astrocytes play a critical role in potassium clearance and ECS shrinkage.
- Different cotransporters are necessary to achieve observed levels of ECS shrinkage.
- The model predicts that the combined action of NBC and NKCC1 enhances ECS shrinkage.
- Empirical data supports the model's predictions regarding ion concentrations during neuronal activity.
- The study provides a framework for future experiments on astrocyte-neuron interactions.
- The model suggests that astrocytes are the main water sink during ECS shrinkage.
Takeaway
When neurons get excited, the space around them shrinks because of how potassium and sodium move in and out of nearby star-shaped brain cells called astrocytes.
Methodology
The study developed five dynamic models to analyze ECS shrinkage based on ion transport mechanisms during neuronal activity.
Limitations
The model does not account for all possible membrane processes and assumes no water exchange with neurons.
Digital Object Identifier (DOI)
Want to read the original?
Access the complete publication on the publisher's website