Effects of antidiuretic hormone on the electrical properties of canine tracheal epithelium.
The canine tracheal epithelium causes net transport of Cl- from serosa to mucosa and of Na+ from mucosa to serosa. These processes are manifested by the short-circuit current which represents the algebraic sum of both fluxes. Antidiuretic hormone (ADH) alters the permeability of several epithelia. This work examines the effect and possible mechanism of action of ADH on the potential difference (PD), short-circuit current (ISC) and conductance (G) of canine tracheal epithelium. The epithelium was mounted in Ussing-type chambers containing Krebs-Henseleit solution at 37 degrees C (pH 7.4) and bubbled with 95% O2 and 5% CO2. PD was recorded on an Cole-Parmer recorder by means of the classical technique and ISC was recorded automatically using a voltage clamp. ADH (mucosal surface) significantly decreased PD, ISC and G in a dose-dependent fashion. Similar doses of ADH applied to the serosal side did not produce a significant effect. Angiotensin II (Agt II, serosal side) and amphotericin B (mucosal side) reversed the depressor effect of mucosal ADH. The effect of ADH was less when the Cl- serosa to mucosa movement was blocked by pretreatment with serosal furosemide. It is considered that ADH blocks apical membrane Cl-channels and that angiotensin reverses this effect by increasing apical membrane permeability to Cl-. Amphotericin B reverses the effect of ADH possibly by increasing Na+ absorption.
Department of Physiological Sciences, Faculty of Biological and Natural Sciences, University of Concepción, Chile.
S M
SM
Palacios
G M
GM
Contreras
B C
BC
Norris
V R
VR
Neumann
J B
JB
Concha
D000666:Amphotericin B / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D004285:Dogs; D004594:Electrophysiology; D004848:Epithelium / Q000502:physiology; D005665:Furosemide / Q000494:pharmacology; D066298:In Vitro Techniques; D009130:Muscle, Smooth / Q000502:physiology*; D014132:Trachea / Q000502:physiology; D014667:Vasopressins / Q000494:pharmacology*
D014667:Vasopressins; D000804:Angiotensin II; D005665:Furosemide; D000666:Amphotericin B