title: Ussing chamber for high-frequency transmural impedance analysis of epithelial tissues.
abstract: An Ussing chamber was designed for impedance analysis of epithelial tissue and optimized for the use of high-frequency alternating current stimuli. Shielded voltage electrodes, located axially within the electric field of the Ussing chamber, minimized the reactive properties of the set-up. By vectorial subtraction, the small reactive contribution of the optimized Ussing chamber was completely compensated for. This method allowed for transmural impedance measurements in a frequency range of 1-65 kHz. For the first time, Nyquist plots of cultured intestinal cell monolayers (HT-29/B6) are presented. The epithelial monolayers in different stages of confluence showed the impedance locus as a semicircle, with the high frequency end close to the origin. These epithelial monolayers could be modeled by a simple RC-parallel circuit without a series resistance.
authors.affiliation: Department of Clinical Physiology, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Germany.
authors.forename: A H
authors.initials: AH
authors.lastname: Gitter
authors.forename: J D
authors.initials: JD
authors.lastname: Schulzke
authors.forename: D
authors.initials: D
authors.lastname: Sorgenfrei
authors.forename: M
authors.initials: M
authors.lastname: Fromm
mesh_terms: D017097:Electric Impedance; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods*; D019073:HT29 Cells / Q000502:physiology*; D006801:Humans