The Basis of Higher Na+ Transport by Inner Medullary Collecting Duct Cells from Dahl Salt-Sensitive Rats: Implicating the Apical Membrane Na+ Channel

The Basis of Higher Na+ Transport by Inner Medullary Collecting Duct Cells from Dahl... The present experiments were designed to examine the function of Na/K pumps from Dahl salt-sensitive (S) and salt-resistant (R) rats. Previous reports have suggested that there is a difference in primary sequence in the α1 subunit, the major Na/K pump isoform in the kidney. This sequence difference might contribute to differences in NaCl excretion in these two strains which in turn could influence the systemic blood pressure. Using ``back-door'' phosphorylation of pumps isolated from basolateral membranes of kidney cortex, we found no differences between S and R strains. We also examined the Na/K pumps from cultured inner medullary collecting duct (IMCD) cells. This approach takes advantage of the fact that monolayers cultured from S rats transport about twice as much Na+ as monolayers cultured from R rats. In cells whose apical membrane was made permeable with amphotericin B, comparison of the affinities for ouabain, Na+, and K+, respectively, showed only small or no differences between S and R monolayers. Ouabain binding showed no difference in the number of Na/K pumps on the basolateral membrane of cultured cells, despite a 2-fold difference in Na+ transport rates. The analysis of the steady-state Na+ transport indicates that Na/K pumps in IMCD monolayers from S rats operate at a higher fraction of their maximum capacity than do pumps in monolayers from R rats. The results, taken together, suggest that the major reason for the higher rate of Na+ transport in S monolayers is because of a primary increase in the conductive permeability of the apical membrane to Na+. They suggest that the epithelial Na+ channel is intrinsically different or differently regulated in S and R rats. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

The Basis of Higher Na+ Transport by Inner Medullary Collecting Duct Cells from Dahl Salt-Sensitive Rats: Implicating the Apical Membrane Na+ Channel

Loading next page...
 
/lp/springer_journal/the-basis-of-higher-na-transport-by-inner-medullary-collecting-duct-N1WgjiQ33D
Publisher
Springer-Verlag
Copyright
Copyright © Inc. by 1997 Springer-Verlag New York
Subject
Life Sciences; Biochemistry, general; Human Physiology
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s002329900182
Publisher site
See Article on Publisher Site

Abstract

The present experiments were designed to examine the function of Na/K pumps from Dahl salt-sensitive (S) and salt-resistant (R) rats. Previous reports have suggested that there is a difference in primary sequence in the α1 subunit, the major Na/K pump isoform in the kidney. This sequence difference might contribute to differences in NaCl excretion in these two strains which in turn could influence the systemic blood pressure. Using ``back-door'' phosphorylation of pumps isolated from basolateral membranes of kidney cortex, we found no differences between S and R strains. We also examined the Na/K pumps from cultured inner medullary collecting duct (IMCD) cells. This approach takes advantage of the fact that monolayers cultured from S rats transport about twice as much Na+ as monolayers cultured from R rats. In cells whose apical membrane was made permeable with amphotericin B, comparison of the affinities for ouabain, Na+, and K+, respectively, showed only small or no differences between S and R monolayers. Ouabain binding showed no difference in the number of Na/K pumps on the basolateral membrane of cultured cells, despite a 2-fold difference in Na+ transport rates. The analysis of the steady-state Na+ transport indicates that Na/K pumps in IMCD monolayers from S rats operate at a higher fraction of their maximum capacity than do pumps in monolayers from R rats. The results, taken together, suggest that the major reason for the higher rate of Na+ transport in S monolayers is because of a primary increase in the conductive permeability of the apical membrane to Na+. They suggest that the epithelial Na+ channel is intrinsically different or differently regulated in S and R rats.

Journal

The Journal of Membrane BiologySpringer Journals

Published: Mar 1, 1997

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