The influence of hypotonicity on large-conductance calcium-activated potassium channels in human retinal pigment epithelial cells

Shwu Jiuan Sheu, Sheng Nan Wu, Dan Ning Hu, Jane Fane Chen

研究成果: Article

6 引文 斯高帕斯(Scopus)

摘要

The aim of this study was to characterize the effects of hypotonicity on the activity of large-conductance Ca2+-activated K+ (BKCa) channels in human retinal pigment epithelial (RPE R-50) cells. Effects of hypotonicity on ion currents were investigated with the aid of the patch-clamp technique. A regulatory volume decrease in response to a hypotonic solution (200 mOsm/L) was observed that could be blunted by paxilline. In whole-cell current recordings, a hypotonic solution (200 mOsm/L) reversibly increased the amplitude of K+ outward currents (IK). The increase of IK could be reversed by iberiotoxin (200 nM), paxilline (1 μM), or tetrandrine (5 μM), but not by glibenclamide (10 μM), disulphonic acid (DIDS) (100 μM), or dequalinium dichloride (10 μM). In RPE R-50 cells pretreated with thapsigargin, aristolochic acid, or pertussis toxin, the increased amplitude of IK in response to hypotonicity was unaltered. In cell-attached patches, an increase in BKCa-channel activity was observed during hypotonicity-induced cell swelling. The enhanced channel activity elicited under this condition was mainly mediated by an increase in the number of long-lived openings. These findings support the evidence for the coupling of volume swelling to the functional activity of BKCa channels.

原文English
頁(從 - 到)563-575
頁數13
期刊Journal of Ocular Pharmacology and Therapeutics
20
發行號6
DOIs
出版狀態Published - 2004 十二月 1

All Science Journal Classification (ASJC) codes

  • Ophthalmology
  • Pharmacology
  • Pharmacology (medical)

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