What we talk about when we talk about capacitance measured with the voltage-clamp step method
Capacitance is a fundamental neuronal property. One common way to measure capacitance is to deliver a small voltage-clamp step that is long enough for the clamp current to come to steady state, and then to divide the integrated transient charge by the voltage-clamp step size. In an isopotential neur...
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| Format: | Online |
| Language: | English |
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Springer US
2011
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| Online Access: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3273682/ |
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pubmed-3273682 |
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pubmed-32736822012-02-17 What we talk about when we talk about capacitance measured with the voltage-clamp step method Taylor, Adam L. Article Capacitance is a fundamental neuronal property. One common way to measure capacitance is to deliver a small voltage-clamp step that is long enough for the clamp current to come to steady state, and then to divide the integrated transient charge by the voltage-clamp step size. In an isopotential neuron, this method is known to measure the total cell capacitance. However, in a cell that is not isopotential, this measures only a fraction of the total capacitance. This has generally been thought of as measuring the capacitance of the “well-clamped” part of the membrane, but the exact meaning of this has been unclear. Here, we show that the capacitance measured in this way is a weighted sum of the total capacitance, where the weight for a given small patch of membrane is determined by the voltage deflection at that patch, as a fraction of the voltage-clamp step size. This quantifies precisely what it means to measure the capacitance of the “well-clamped” part of the neuron. Furthermore, it reveals that the voltage-clamp step method measures a well-defined quantity, one that may be more useful than the total cell capacitance for normalizing conductances measured in voltage-clamp in nonisopotential cells. Springer US 2011-06-29 2012-02 /pmc/articles/PMC3273682/ /pubmed/21713564 http://dx.doi.org/10.1007/s10827-011-0346-8 Text en © The Author(s) 2011 |
| repository_type |
Open Access Journal |
| institution_category |
Foreign Institution |
| institution |
US National Center for Biotechnology Information |
| building |
NCBI PubMed |
| collection |
Online Access |
| language |
English |
| format |
Online |
| author |
Taylor, Adam L. |
| spellingShingle |
Taylor, Adam L. What we talk about when we talk about capacitance measured with the voltage-clamp step method |
| author_facet |
Taylor, Adam L. |
| author_sort |
Taylor, Adam L. |
| title |
What we talk about when we talk about capacitance measured with the voltage-clamp step method |
| title_short |
What we talk about when we talk about capacitance measured with the voltage-clamp step method |
| title_full |
What we talk about when we talk about capacitance measured with the voltage-clamp step method |
| title_fullStr |
What we talk about when we talk about capacitance measured with the voltage-clamp step method |
| title_full_unstemmed |
What we talk about when we talk about capacitance measured with the voltage-clamp step method |
| title_sort |
what we talk about when we talk about capacitance measured with the voltage-clamp step method |
| description |
Capacitance is a fundamental neuronal property. One common way to measure capacitance is to deliver a small voltage-clamp step that is long enough for the clamp current to come to steady state, and then to divide the integrated transient charge by the voltage-clamp step size. In an isopotential neuron, this method is known to measure the total cell capacitance. However, in a cell that is not isopotential, this measures only a fraction of the total capacitance. This has generally been thought of as measuring the capacitance of the “well-clamped” part of the membrane, but the exact meaning of this has been unclear. Here, we show that the capacitance measured in this way is a weighted sum of the total capacitance, where the weight for a given small patch of membrane is determined by the voltage deflection at that patch, as a fraction of the voltage-clamp step size. This quantifies precisely what it means to measure the capacitance of the “well-clamped” part of the neuron. Furthermore, it reveals that the voltage-clamp step method measures a well-defined quantity, one that may be more useful than the total cell capacitance for normalizing conductances measured in voltage-clamp in nonisopotential cells. |
| publisher |
Springer US |
| publishDate |
2011 |
| url |
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3273682/ |
| _version_ |
1611504168751595520 |