Linked Life Data

6090670

Source:http://linkedlifedata.com/resource/pubmed/id/6090670

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1984-11-6
pubmed:abstractText
Inhibition of the Na conductance of the apical membrane of the toad urinary bladder by amiloride, alkali cations and protons was voltage dependent. Bladders were bathed with a high K-sucrose serosal medium to reduce series basal-lateral resistance and potential difference. Transepithelial current-voltage relationships were measured over a voltage range of +/- 200 mV with a voltage ramp of frequency 0.5 to 1 Hz. Na channel I-V relationships were obtained by subtraction of currents measured in the presence of maximal doses of amiloride (10 to 20 microM). With submaximal doses of amiloride (0.05 to 0.5 microM), the degree of inhibition of the Na channel current (INa) increased as the mucosal potential was made more positive. The data can be reasonably well explained by assuming that amiloride blocks Na transport by binding to a site which senses approximately 12% of the transmembrane voltage difference. INa was reduced in a qualitatively similar voltage-dependent manner by mucosal K, Rb, Cs and Tl (approximately 100 mM) and by mucosal H (approximately 1 mM). Block by these cations cannot be explained in terms of interactions with a single membrane-voltage-sensing site; a model in which there are two or more blocking sites in series provides a better description of the data. On the other hand, amiloride block was reduced competitively by mucosal Na and K, suggesting that occupation of the channel by one cation excludes occupancy by the others. ADH and ouabain also reduce the apparent affinity of amiloride for its blocking site. Thus, intracellular Na may also compete with amiloride for occupancy of the channel.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0022-2631
pubmed:author
pubmed:issnType
Print
pubmed:volume
80
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
153-65
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
Voltage-dependent block by amiloride and other monovalent cations of apical Na channels in the toad urinary bladder.
pubmed:publicationType
Journal Article, Comparative Study, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't