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Updated: Aug 13, 2025
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Making, Testing, and Using Potassium Ion Selective Microelectrodes in Tissue Slices of Adult Brain
Published on: May 7, 2018
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Activity-Dependent Fluctuations in Interstitial [K+]: Investigations Using Ion-Sensitive Microelectrodes
Hana Beswick-Jones1, Amy J Hopper1, Angus M Brown1,2
1School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK.
Molecules (Basel, Switzerland)
|January 21, 2023
Summary
Neurons release potassium (K+) during action potential firing, which astrocytes buffer to maintain function. Impaired buffering in conditions like ischemia can disrupt neuronal activity, measurable with K+-sensitive microelectrodes.
Area of Science:
- Neuroscience
- Cellular Physiology
Background:
- Neurons release potassium ions (K+) into the interstitial space during action potential firing to restore resting membrane potential.
- Interstitial K+ accumulation can depolarize the K+ reversal potential (EK), inhibiting further action potentials.
- Astrocytes buffer interstitial K+ via an energy-dependent process, maintaining neuronal function.
Purpose of the Study:
- To explain the physiological role of potassium buffering by astrocytes.
- To highlight the consequences of impaired K+ buffering in pathological conditions.
- To emphasize the utility of K+-sensitive microelectrodes in monitoring interstitial K+.
Main Methods:
- Review of established knowledge on neuronal K+ transport and astrocytic buffering.
- Discussion of pathological conditions affecting energy metabolism and K+ homeostasis.
- Highlighting the application of K+-sensitive microelectrodes for real-time interstitial [K+] measurement.
Main Results:
- Potassium efflux during neuronal activity leads to interstitial K+ accumulation.
- Astrocytic buffering is crucial for preventing excessive interstitial K+ buildup and maintaining neuronal excitability.
- Pathological states compromising energy production exacerbate interstitial K+ accumulation, disrupting neuronal function.
Conclusions:
- Astrocytic K+ buffering is essential for neuronal function, preventing activity-dependent depolarization.
- Disruptions in energy metabolism compromise astrocytic function, leading to pathological K+ accumulation and neuronal dysfunction.
- K+-sensitive microelectrodes provide a critical tool for real-time assessment of interstitial K+ dynamics in physiological and pathological states.
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