Document Detail


Single-channel biophysical and pharmacological characterizations of native human large-conductance calcium-activated potassium channels in freshly isolated detrusor smooth muscle cells.
MedLine Citation:
PMID:  23344746     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Recent studies have demonstrated the importance of large-conductance Ca(2+)-activated K(+) (BK) channels in detrusor smooth muscle (DSM) function in vitro and in vivo. However, in-depth characterization of human native DSM single BK channels has not yet been provided. Here, we conducted single-channel recordings from excised patches from native human DSM cells. Inside-out and outside-out recordings in high K(+) symmetrical solution (containing 140 mM KCl and ~300 nM free Ca(2+)) showed single-channel conductance of 215-220 pS, half-maximum constant for activation of ~+75 to +80 mV, and low probability of opening (P o) at +20 mV that increased ~10-fold at +40 mV and ~60-fold at +60 mV. Using the inside-out configuration at +30 mV, reduction of intracellular [Ca(2+)] from ~300 nM to Ca(2+)-free decreased the P o by ~85 %, whereas elevation to ~800 nM increased P o by ~50-fold. The BK channel activator NS1619 (10 μM) enhanced the P o by ~10-fold at +30 mV; subsequent application of the selective BK channel inhibitor paxilline (500 nM) blocked the activity. Changes in intracellular [Ca(2+)] or the addition of NS1619 did not significantly alter the current amplitude or single-channel conductance. This is the first report to provide biophysical and pharmacological profiles of native human DSM single BK channels highlighting their importance in regulating human DSM excitability.
Authors:
John Malysz; Eric S Rovner; Georgi V Petkov
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2013-01-24
Journal Detail:
Title:  Pflügers Archiv : European journal of physiology     Volume:  465     ISSN:  1432-2013     ISO Abbreviation:  Pflugers Arch.     Publication Date:  2013 Jul 
Date Detail:
Created Date:  2013-07-01     Completed Date:  2014-01-22     Revised Date:  2014-07-02    
Medline Journal Info:
Nlm Unique ID:  0154720     Medline TA:  Pflugers Arch     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  965-75     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Action Potentials*
Aged
Calcium / metabolism
Cells, Cultured
Female
Humans
Large-Conductance Calcium-Activated Potassium Channels / antagonists & inhibitors,  metabolism*
Male
Middle Aged
Myocytes, Smooth Muscle / metabolism,  physiology*
Potassium / metabolism
Potassium Channel Blockers / pharmacology
Urinary Bladder / cytology
Grant Support
ID/Acronym/Agency:
DK084284/DK/NIDDK NIH HHS; R01 DK084284/DK/NIDDK NIH HHS
Chemical
Reg. No./Substance:
0/Large-Conductance Calcium-Activated Potassium Channels; 0/Potassium Channel Blockers; RWP5GA015D/Potassium; SY7Q814VUP/Calcium
Comments/Corrections

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