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dc.contributor.authorEhrhardt, Anka G.
dc.contributor.authorFrankish, Neil
dc.contributor.authorIsenberg, Gerrit
dc.date2022-08-11T08:09:34.000
dc.date.accessioned2022-08-23T16:35:46Z
dc.date.available2022-08-23T16:35:46Z
dc.date.issued1996-11-01
dc.date.submitted2009-03-26
dc.identifier.citation<p>J Physiol. 1996 Nov 1;496 ( Pt 3):663-76.</p>
dc.identifier.issn0022-3751 (Print)
dc.identifier.pmid8930834
dc.identifier.urihttp://hdl.handle.net/20.500.14038/38637
dc.description.abstract1. DDT1 MF-2 smooth muscle cells responded to the bath application of histamine or ATP with an increase in the cytosolic Ca2+ concentration ([Ca2+]c) and the whole-cell K+ current, IK(BA). 2. In cell-attached patches, histamine (100 microM) activated currents through a 200 pS K+ channel ('BKA' channel). In the absence of agonists, the BKA channel was activated by excision of the patch. Both histamine and patch excision increased the channel activity (NPo; where N is the number of channels per patch and Po is the open probability) by reducing the long closures between the bursts of openings. 3. In inside-out patches, the BKA channel had a conductance of 201 +/- 4 pS (symmetrical solutions of 150 mM KCl, 2 mM MgCl2 and 2 mM EGTA). Replacement of K+ in the patch electrode by Na+, Li+ or Cs+ prevented the flow of inward currents and reduced the outward K+ conductance to 113 pS. 4. NPo was insensitive to changes in [Ca2+]c from 10 nM to 1 microM. NPo was also not modified either by cytosolic Na+, ATP, GTP, GTP gamma S, dithiothreitol or TEA (10 mM) or by extracellular 4-aminopyridine (5 mM), glibenclamide (20 microM) or TEA (10 mM). The BKA channel was blocked by 5 mM intracellular BaCl2 or by 10 nM extracellular iberiotoxin. 5. In cell-attached patches, BKA channel activity could be induced by 1 microM cytochalasin B, applied either through the patch pipette or in the bath solution. The effects of cytochalasin B, of patch excision, or of histamine on NPo were not additive but saturative. 6. Whole DDT1 MF-2 cells had resting potentials of -10 mV, dominated by the chloride conductance; the resting potential changed to -82 mV when the K+ conductance was increased by cytochalasin B or by histamine. The effects of cytochalasin B and histamine on IK(BA) were not additive but saturative. 7. We discuss the hypothesis that the interaction between the cytoskeleton and the BKA channel promotes the long channel closures; depolymerization of F-actin may constitute a mechanism by which the agonists histamine or ATP disinhibit BKA channel activity.
dc.language.isoen_US
dc.relation<p><a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&list_uids=8930834&dopt=Abstract">Link to Article in PubMed</a></p>
dc.relation.urlhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC1160854/
dc.subjectAdenosine Triphosphate
dc.subjectAnimals
dc.subjectCalcium
dc.subjectCell Line
dc.subjectCricetinae
dc.subjectCytochalasin B
dc.subjectCytoskeleton
dc.subjectCytosol
dc.subjectElectric Conductivity
dc.subjectHistamine
dc.subjectIon Channel Gating
dc.subjectKinetics
dc.subjectMale
dc.subjectMuscle, Smooth
dc.subjectPatch-Clamp Techniques
dc.subjectPotassium Channels
dc.subjectReceptors, Purinergic
dc.subjectTime Factors
dc.subjectVas Deferens
dc.subjectLife Sciences
dc.subjectMedicine and Health Sciences
dc.titleA large-conductance K+ channel that is inhibited by the cytoskeleton in the smooth muscle cell line DDT1 MF-2
dc.typeJournal Article
dc.source.journaltitleThe Journal of physiology
dc.source.volume496 ( Pt 3)
dc.identifier.legacycoverpagehttps://escholarship.umassmed.edu/oapubs/1498
dc.identifier.contextkey798473
html.description.abstract<p>1. DDT1 MF-2 smooth muscle cells responded to the bath application of histamine or ATP with an increase in the cytosolic Ca2+ concentration ([Ca2+]c) and the whole-cell K+ current, IK(BA). 2. In cell-attached patches, histamine (100 microM) activated currents through a 200 pS K+ channel ('BKA' channel). In the absence of agonists, the BKA channel was activated by excision of the patch. Both histamine and patch excision increased the channel activity (NPo; where N is the number of channels per patch and Po is the open probability) by reducing the long closures between the bursts of openings. 3. In inside-out patches, the BKA channel had a conductance of 201 +/- 4 pS (symmetrical solutions of 150 mM KCl, 2 mM MgCl2 and 2 mM EGTA). Replacement of K+ in the patch electrode by Na+, Li+ or Cs+ prevented the flow of inward currents and reduced the outward K+ conductance to 113 pS. 4. NPo was insensitive to changes in [Ca2+]c from 10 nM to 1 microM. NPo was also not modified either by cytosolic Na+, ATP, GTP, GTP gamma S, dithiothreitol or TEA (10 mM) or by extracellular 4-aminopyridine (5 mM), glibenclamide (20 microM) or TEA (10 mM). The BKA channel was blocked by 5 mM intracellular BaCl2 or by 10 nM extracellular iberiotoxin. 5. In cell-attached patches, BKA channel activity could be induced by 1 microM cytochalasin B, applied either through the patch pipette or in the bath solution. The effects of cytochalasin B, of patch excision, or of histamine on NPo were not additive but saturative. 6. Whole DDT1 MF-2 cells had resting potentials of -10 mV, dominated by the chloride conductance; the resting potential changed to -82 mV when the K+ conductance was increased by cytochalasin B or by histamine. The effects of cytochalasin B and histamine on IK(BA) were not additive but saturative. 7. We discuss the hypothesis that the interaction between the cytoskeleton and the BKA channel promotes the long channel closures; depolymerization of F-actin may constitute a mechanism by which the agonists histamine or ATP disinhibit BKA channel activity.</p>
dc.identifier.submissionpathoapubs/1498
dc.contributor.departmentProgram in Molecular Medicine
dc.source.pages663-76


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