Two types of chloride channels in hen colon epithelial cells identified by patch-clamp experiments
✍ Scribed by Horst Fischer; Wolfgang Kromer; Wolfgang Clauss
- Book ID
- 104688707
- Publisher
- Springer-Verlag
- Year
- 1991
- Tongue
- English
- Weight
- 639 KB
- Volume
- 161
- Category
- Article
- ISSN
- 0174-1578
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✦ Synopsis
Freshly isolated epithelial cells from hen colon were investigated using the patch-clamp technique. The aim of this investigation was to characterise the cellular conducting site for Cl- secretion. In cell-attached mode two types of Cl(-)-channels were found. Both showed distinct outward rectification. The channel types differed in single channel conductances and the marked voltage dependence of the open probabilities. A low conductance Cl(-)-channel was observed with a mean conductance at negative holding potentials of g- = 9 pS, and of g+ = 34 pS at positive potentials. This channel was predominantly open at negative potentials, corresponding to cell hyperpolarization. The second channel type observed had conductances of g- = 35 pS and g+ = 77 pS, and showed increasing open probabilities with increasing holding potentials (cell depolarisation). Both channel types were blockable by the Cl(-)-channel blocker NPPB. These data in combination with previously published transepithelial transport data on hen colon indicate that these channels are the Cl- secretory sites in colon epithelium.