Linked Life Data

9698322

Source:http://linkedlifedata.com/resource/pubmed/id/9698322

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
16
pubmed:dateCreated
1998-9-9
pubmed:abstractText
By affecting the activity of the adaptation motor, Ca2+ entering a hair bundle through mechanoelectrical transduction channels regulates the sensitivity of the bundle to stimulation. For adaptation to set the position of mechanosensitivity of the bundle accurately, the free Ca2+ concentration in stereocilia must be tightly controlled. To define the roles of Ca2+-regulatory mechanisms and thus the factors influencing adaptation motor activity, we used confocal microscopy to detect Ca2+ entry into and clearance from individual stereocilia of hair cells dialyzed with the Ca2+ indicator fluo-3. We also developed a model of stereociliary Ca2+ homeostasis that incorporates four regulatory mechanisms: Ca2+ clearance from the bundle by free diffusion in one dimension, Ca2+ extrusion by pumps, Ca2+ binding to fixed stereociliary buffers, and Ca2+ binding to mobile buffers. To test the success of the model, we compared the predicted profiles of fluo-3 fluorescence during the response to mechanical stimulation with the fluorescence patterns measured in individual stereocilia. The results indicate that all four of the Ca2+ regulatory mechanisms must be included in the model to account for the observed rate of clearance of the ion from the hair bundle. The best fit of the model suggests that a free Ca2+ concentration of a few micromolar is attained near the adaptation motor after transduction-channel opening. The free Ca2+ concentration substantially rises only in the upper portion of the stereocilium and quickly falls toward the resting level as adaptation proceeds.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0270-6474
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
18
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6300-18
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Regulation of free Ca2+ concentration in hair-cell stereocilia.
pubmed:affiliation
Howard Hughes Medical Institute and Laboratory of Sensory Neuroscience, The Rockefeller University, New York, New York 10021-6399, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't