title: Two types of chloride channel in the apical membrane of rat choroid plexus epithelial cells.
abstract: The patch clamp technique has been used to study ion channel activity in the apical (ventricular) membrane of epithelial cells from the rat choroid plexus. Two different classes of Cl(-)-selective channel were identified. A low conductance (26 pS) channel which was the predominant feature in cell-attached and inside-out patches. The occurrence of this channel appeared to increase in tissue bathed in forskolin. It was activated in inside-out patches by increasing the Ca2+ concentration at the intracellular face of the membrane and by depolarising potentials. The second class of channel was observed infrequently (2% of patches) and appeared to be similar to 'maxi'-Cl- channels which have been described in many other cell types. It had a conductance of 320 pS, opened to sub-conductance levels and displayed a marked voltage dependence in inside-out patches. The possible contribution of these channels to Cl- transport during the production of cerebrospinal fluid (CSF) is discussed.
authors.affiliation: Department of Physiological Sciences, University of Manchester, UK.
authors.forename: C
authors.initials: C
authors.lastname: Garner
authors.forename: P D
authors.initials: PD
authors.lastname: Brown
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000737:chemistry*; D018118:Chloride Channels; D002712:Chlorides; D002831:Choroid Plexus / Q000737:chemistry* / Q000166:cytology; D004553:Electric Conductivity / Q000502:physiology; D004848:Epithelium / Q000737:chemistry; D005260:Female; D008297:Male; D008565:Membrane Proteins / Q000145:classification*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D018118:Chloride Channels; D002712:Chlorides; D008565:Membrane Proteins