title: Stretch-stimulated activity of large conductance calcium-activated potassium channels in human retinal pigment epithelial cells.
abstract: OBJECTIVE
  The aim of this study was to investigate the effect of membrane stretch on the activity of BK(Ca) channels and determine whether change in BK(Ca)-channel activity induced by membrane stretch can be altered in the presence of riluzole.
  
  
  METHODS
  The effect and mechanisms of membrane stretch on the activity of large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels in human retinal pigment epithelial (RPE) cells were investigated using the patch-clamp technique.
  
  
  RESULTS
  In cell-attached patches, an increase in BK(Ca)-channel activity was induced by membrane stretch, which is mainly mediated by the increase in the number of long-lived openings. With inside-out patches, application of pipette suction did not modify single-channel conductance of BK(Ca) channels; however, it did enhance the channel activity. Membrane stretch-induced channel activity was found to be independent of the level of intracellular Ca(2+). Membrane stretch also potentiated riluzole-stimulated BK(Ca)-channel activity.
  
  
  CONCLUSIONS
  BK(Ca) channel can be stimulated by membrane stretch in human RPE cells. During an increase in tensile strength of RPE, the BK(Ca) channel might exert a protective action against deleterious tension by promoting a hyperpolarizing outflow that forces the cell to rest.
authors.affiliation: Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung City, Taiwan, Republic of China. sjsheu@vghks.gov.tw
authors.forename: Shwu-Jiuan
authors.initials: SJ
authors.lastname: Sheu
authors.forename: Sheng-Nan
authors.initials: SN
authors.lastname: Wu
authors.forename: Dan-Ning
authors.initials: DN
authors.lastname: Hu
mesh_terms: D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism* / Q000502:physiology; D004847:Epithelial Cells / Q000378:metabolism* / Q000502:physiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006801:Humans; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D019782:Riluzole / Q000494:pharmacology; D013718:Tensile Strength / Q000502:physiology
chemical_list: D018691:Excitatory Amino Acid Antagonists; D051036:Large-Conductance Calcium-Activated Potassium Channels; D019782:Riluzole