Mitochondria-rich Cells and Voltage-activated Chloride Current in Toad Skin Epithelium: Analysis with the Scanning Vibrating Electrode Technique

Mitochondria-rich Cells and Voltage-activated Chloride Current in Toad Skin Epithelium: Analysis... The pathway for the voltage-activated chloride current across isolated toad skin was analyzed using a scanning 2D-vibrating voltage probe technique, which permits discrimination of local current peaks if their origins are more than 50 μm apart. The epithelium was separated from the corial connective tissue after enzymatic digestion with collagenase. Cl− current was activated by voltage clamping the transepithelial potential to 60–100 mV, serosa positive. Activated inward current was between 85 and 450 μA/cm2. In more than 25 tissue areas of 150 × 100 μm from 10 animals, which were automatically scanned with the vibrating probe, between 0 and 4 peaks of elevated local current (up to 800 μA/cm2) could be identified in individual fields. The density of current peaks, which were generally located at sites of mitochondria-rich (MR) cells, was less than 10% of the density of microscopically identified MR cells. The total current across individual sites of elevated conductance was 3.9 ± 0.6 nA. Considering the density of peaks, they account for 17 ± 2.5% of the applied transepithelial clamping current. The time course of current activation over previously identified conductive sites was in most cases unrelated to that of the total transepithelial current. Moreover, initially active sites could spontaneously inactivate. The results indicate that detection of elevated current above some MR cells is not sufficient to verify these cells as the pathway for transepithelial voltage-activated Cl− current. Since the major fraction of activated current is apparently not associated with a route through MR cells, channel-like structures in the tight junctions of the paracellular pathway must be considered as an alternative possibility. Current peaks over MR cells could be due to high density of such sites in tight junctions between MR and surrounding principal cells. Improvement of the spatial resolution of the vibrating probe is required to verify this view. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Mitochondria-rich Cells and Voltage-activated Chloride Current in Toad Skin Epithelium: Analysis with the Scanning Vibrating Electrode Technique

Loading next page...
 
/lp/springer_journal/mitochondria-rich-cells-and-voltage-activated-chloride-current-in-toad-LB86oGnvAw
Publisher
Springer-Verlag
Copyright
Copyright © Inc. by 1998 Springer-Verlag New York
Subject
Life Sciences; Biochemistry, general; Human Physiology
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s002329900320
Publisher site
See Article on Publisher Site

Abstract

The pathway for the voltage-activated chloride current across isolated toad skin was analyzed using a scanning 2D-vibrating voltage probe technique, which permits discrimination of local current peaks if their origins are more than 50 μm apart. The epithelium was separated from the corial connective tissue after enzymatic digestion with collagenase. Cl− current was activated by voltage clamping the transepithelial potential to 60–100 mV, serosa positive. Activated inward current was between 85 and 450 μA/cm2. In more than 25 tissue areas of 150 × 100 μm from 10 animals, which were automatically scanned with the vibrating probe, between 0 and 4 peaks of elevated local current (up to 800 μA/cm2) could be identified in individual fields. The density of current peaks, which were generally located at sites of mitochondria-rich (MR) cells, was less than 10% of the density of microscopically identified MR cells. The total current across individual sites of elevated conductance was 3.9 ± 0.6 nA. Considering the density of peaks, they account for 17 ± 2.5% of the applied transepithelial clamping current. The time course of current activation over previously identified conductive sites was in most cases unrelated to that of the total transepithelial current. Moreover, initially active sites could spontaneously inactivate. The results indicate that detection of elevated current above some MR cells is not sufficient to verify these cells as the pathway for transepithelial voltage-activated Cl− current. Since the major fraction of activated current is apparently not associated with a route through MR cells, channel-like structures in the tight junctions of the paracellular pathway must be considered as an alternative possibility. Current peaks over MR cells could be due to high density of such sites in tight junctions between MR and surrounding principal cells. Improvement of the spatial resolution of the vibrating probe is required to verify this view.

Journal

The Journal of Membrane BiologySpringer Journals

Published: Jan 15, 1998

There are no references for this article.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off