Extracellular Ion Measurement
Extracellular Ion Measurement - Related Videos
09:18
Measurement of Extracellular Ion Fluxes Using the Ion-selective Self-referencing Microelectrode Technique
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Cited by 6 •
2015
Transporters in cell membranes allow differential segregation of ions across cell membranes or cell layers and play crucial roles during tissue physiology, repair and pathology. We describe the ion-selective self-referencing microelectrode that allows the measurement of specific ion fluxes at single cells and tissues in vivo.
11:08
Double-barreled and Concentric Microelectrodes for Measurement of Extracellular Ion Signals in Brain Tissue
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Cited by 19 •
2015
We demonstrate the fabrication, calibration and properties of two types of ion-selective microelectrodes (double-barreled and concentric) for measurement of ion concentrations in brain tissue. These are then used in the mouse hippocampal slice preparation to show that excitatory activity changes both extracellular potassium and sodium concentrations.
03:01
Characterizing Extracellular Space in a Brain Slice Using Ion-Selective and Iontophoresis Microelectrodes
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2025
This video demonstrates how to characterize the extracellular space in a brain slice by using ion-selective and iontophoresis microelectrodes to measure and compare electrical signals. This process helps determine the space's volume fraction and degree of twisting.
07:32
Dynamic Electrochemical Measurement of Chloride Ions
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Cited by 5 •
2016
Dynamic measurement of chloride ions is presented. Transition time of an Ag/AgCl electrode, during a chronopotentiometric technique, can give the concentration of chloride ions in electrolyte. This method does not require a stable conventional reference electrode.
03:41
Measurement of Evoked Potassium Ion Concentration Dynamics in Coronal Hippocampal Slices
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2025
The video demonstrates evoked potassium ion concentration dynamics on electrical stimulation of mouse coronal hippocampal brain slices. A bipolar stimulating electrode is inserted into the stratum radiatum of the CA3 region in the hippocampus, and a potassium-ion selective electrode is placed in the CA1 stratum radiatum. The electrical stimulation causes an action potential, resulting in potassium ion release. Finally, the lack of evoked potassium ion response in the presence of an inhibitory...
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Their selective membranes are designed to respond preferentially to a particular ion, while related sensors use binding chemistries that recognize the target species. This selectivity allows concentration differences for potassium, sodium, calcium, or chloride to be converted into electrical signals, helping investigators follow chemical changes around neural cells without treating all ions as interchangeable.
The recorded signal provides a quantitative readout of changing ion concentrations outside cells. When paired with observations of neuronal firing or synaptic transmission, these changes can connect cellular activity with alterations in the brain’s chemical and electrical environment. The resulting measurements help reveal how neural systems regulate extracellular composition during normal function and disruption.
Tracking these ions separately allows researchers to examine distinct changes in extracellular composition rather than relying on a single general measure. Such data can be related to ion flux and homeostatic regulation, the processes that maintain appropriate conditions around cells. Comparing measurements across ions may therefore clarify how neural activity changes the surrounding environment.
Repeated measurements during neural activity can show whether extracellular ion levels remain regulated or shift substantially from their usual state. This distinction is important because firing, synaptic transmission, seizures, and ischemia can all be associated with changes in ionic composition. The measurements therefore support analysis of both normal regulation and pathological disruption in neural tissue.
Investigators can collect extracellular ion data during neuronal firing, synaptic transmission, seizures, or ischemia. These experimental conditions expose different relationships between neural activity and the surrounding ionic environment. Comparing the resulting concentration changes helps researchers determine how activity-related ion flux and failures of regulation contribute to network behavior or neurological disturbances.
A typical approach uses an ion-selective microelectrode or related sensor directed toward the extracellular fluid, selects the ion of interest through a membrane or binding chemistry, and records the resulting electrical signal. Researchers then relate concentration changes to the experimental neural event, such as firing or seizure activity, to interpret ion flux and regulation.
These measurements are particularly informative when researchers need to connect abnormal neural activity with changes in extracellular composition. Seizures and ischemia provide relevant contexts because they can reveal disturbances in ionic regulation alongside network dysfunction. The data can help identify ionic mechanisms underlying neurological disorders, complementing observations of cellular and system-level activity.
Ion measurements provide a chemical perspective that can be aligned with neural events occurring at cellular or network scales. Changes recorded during neuronal firing or synaptic transmission can be examined alongside their broader activity context, while seizure or ischemia measurements reveal disruption. This relationship helps researchers interpret how local ion flux contributes to network function and dysfunction.