Document Detail


Interference of shot noise of open-channel current with analysis of fast gating: patchers do not (Yet) have to care.
MedLine Citation:
PMID:  19551329     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Microsecond gating of ion channels can be evaluated by fitting beta distributions to amplitude histograms of measured time series. The shape of these histograms is determined not only by the rate constants of the gating process (in relation to the filter frequency) but also by baseline noise and shot noise, resulting from the stochastic nature of ion flow. Under normal temporal resolution, the small shot noise can be ignored. This simplification may no longer be legitimate when rate constants reach the range above 1 mus(-1). Here, the influence of shot noise is studied by means of simulated time series for several values of single-channel current of the fully open state and baseline noise. Under realistic optimal conditions (16 pA current, 1 pA noise, 50 kHz bandwidth), ignoring the shot noise leads to an underestimation of the rate constants above 1 mus(-1) by a factor of about 2.5. However, in that range, the scatter of the evaluated rate constants is at least of the same magnitude, obscuring the systematic error. The incorporation of shot noise into the analysis will become more important when amplifiers with significantly reduced noise become available.
Authors:
Indra Schroeder; Ulf-Peter Hansen
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-06-24
Journal Detail:
Title:  The Journal of membrane biology     Volume:  229     ISSN:  1432-1424     ISO Abbreviation:  J. Membr. Biol.     Publication Date:  2009 Jun 
Date Detail:
Created Date:  2009-07-14     Completed Date:  2009-09-24     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0211301     Medline TA:  J Membr Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  153-63     Citation Subset:  IM    
Affiliation:
Department of Structural Biology, University of Kiel, Leibnizstr. 11, 24098, Kiel, Germany. schroeder@bio.tu-darmstadt.de
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MeSH Terms
Descriptor/Qualifier:
Electrophysiology
Ion Channel Gating / physiology*
Kinetics
Markov Chains

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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