Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

pH- and voltage-dependent conductances in toad skin

F Lacaz-Vieira1

  • 1Department of Physiology and Biophysics, University of São Paulo, Brazil.

The Journal of Membrane Biology
|November 1, 1995
PubMed
Summary

This study investigates how protons affect ion channels in toad skin, revealing that increased acidity impairs chloride channel activation and influences proton-gated conductance. These findings shed light on ion transport mechanisms in epithelial tissues.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Lanthanum effect on the dynamics of tight junction opening and closing.

The Journal of membrane biology·2005
Same author

Pulses of cell Ca(2+) and the dynamics of tight junction opening and closing.

The Journal of membrane biology·2004
Same author

Protein kinase inhibitors and the dynamics of tight junction opening and closing in A6 cell monolayers.

The Journal of membrane biology·2001
Same author

Tight junction dynamics: oscillations and the role of protein kinase C.

The Journal of membrane biology·2000
Same author

Small synthetic peptides homologous to segments of the first external loop of occludin impair tight junction resealing.

The Journal of membrane biology·1999
Same author

An automatic temperature-control system for solutions in free flow.

Pflugers Archiv : European journal of physiology·1999

Area of Science:

  • Physiology
  • Biophysics
  • Ion Transport

Background:

  • Mitochondria-rich cells in toad skin play a crucial role in ion and acid-base balance.
  • Apical ion channels, particularly voltage-dependent chloride channels, are key regulators of transepithelial transport.
  • The influence of apical proton concentration on these channels and novel proton-gated conductances remains incompletely understood.

Purpose of the Study:

  • To investigate the interaction of apical protons with voltage-dependent chloride-activated channels in toad skin mitochondria-rich cells.
  • To characterize a novel voltage-dependent proton-activated conductance.
  • To elucidate the impact of varying apical pH on ion channel gating and tissue conductance.

Main Methods:

  • Electrophysiological recordings were performed on toad skins to measure ion conductance.
  • Apical solutions with varying pH levels (from 8 to 4) were applied.
  • Voltage clamping techniques were used to assess voltage-dependent channel kinetics and conductance.
  • Experiments were conducted in the presence and absence of apical chloride ions.

Main Results:

  • Increasing apical proton concentration (acidification) impairs the activation of voltage-dependent chloride channels, slowing kinetics and reducing conductance.
  • This pH effect on chloride channels is voltage-dependent, suggesting protonation sites are within the membrane electric field.
  • A novel voltage-dependent proton-activated conductance was characterized, showing slow activation/deactivation, requirement for negative potentials, and rectification, with a distinct activation threshold around pH 3.

Conclusions:

  • Apical proton concentration significantly modulates the function of voltage-dependent chloride channels in toad skin.
  • A distinct voltage-dependent proton-activated conductance exists, sharing some properties with chloride channels but potentially representing a separate pathway.
  • These findings highlight the complex interplay between protons, voltage, and ion channel activity in regulating epithelial transport.

Related Experiment Videos