Linked Life Data

1383018

Source:http://linkedlifedata.com/resource/pubmed/id/1383018

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1992-11-6
pubmed:abstractText
In patch clamp studies of apical membrane from frog lens epithelium, the most frequently observed channel is 'stretch-activated', highly selective for cations over anions but showing little selectivity for Na+ vs. K+. In normal physiological saline, the open channel conductance is 25-30 pS and quite linear over +/- 100 mV. In the absence of extracellular divalent ions, the open channel conductance for inward current flow increases to about 50 pS at the normal lens resting voltage of -75 mV, whereas the conductance for outward current flow is unaffected. In the intact lens, removal of extracellular divalents causes the input conductance approximately to double and the intracellular voltage to depolarize from -74 to -58 mV. A variety of divalent ions block this change in whole lens conductance and voltage in the same order in which they block the 'stretch channels'. Single voltage-clamped epithelial cells also increase their conductance when Ca2+ is removed from their bathing medium. There are, therefore, some striking parallels between the open channel properties of the 'stretch-activated' cation channel and the response of the whole lens or single lens cells to removal of extracellular Ca2+. There are also inconsistencies. This channel is apparently not open in the normal resting lens so removal of extracellular Ca2+ must cause it to open if it is indeed responsible for the increase in lens conductance. However, we have not been able to demonstrate convincingly an increase in open probability at the single-channel level when external divalents are removed.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0014-4835
pubmed:author
pubmed:issnType
Print
pubmed:volume
55
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
135-44
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Divalent cation effects on lens conductance and stretch-activated cation channels.
pubmed:affiliation
Department of Physiology, Mayo Foundation, Rochester, MN 55905.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't