Linked Life Data

9763471

Source:http://linkedlifedata.com/resource/pubmed/id/9763471

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
20
pubmed:dateCreated
1998-10-23
pubmed:abstractText
Mechanoelectrical transducer currents in turtle auditory hair cells adapt to maintained stimuli via a Ca2+-dependent mechanism that is sensitive to the level of internal calcium buffer. We have used the properties of transducer adaptation to compare the effects of exogenous calcium buffers in the patch electrode solution with those of the endogenous buffer assayed with perforated-patch recording. The endogenous buffer of the hair bundle was equivalent to 0.1-0.4 mM BAPTA and, in a majority of cells, supported adaptation in an external Ca2+ concentration of 70 microM similar to that in turtle endolymph. The endogenous buffer had a higher effective concentration, and the adaptation time constant was faster in cells at the high-frequency end than at the low-frequency end of the cochlea. Experiments using buffers with different Ca2+-binding rates or dissociation constants indicated that the speed of adaptation and the resting open probability of the transducer channels could be differentially regulated and imply that the endogenous buffer must be a fast, high-affinity buffer. In some hair cells, the transducer current did not decay exponentially during a sustained stimulus but displayed damped oscillations at a frequency (58-230 Hz) that depended on external Ca2+ concentration. The gradient in adaptation time constant and the tuned transducer current at physiological levels of calcium buffer and external Ca2+ suggest that transducer adaptation may contribute to hair cell frequency selectivity. The results are discussed in terms of feedback regulation of transducer channels mediated by Ca2+ binding at two intracellular sites.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0270-6474
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
18
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
8261-77
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
The endogenous calcium buffer and the time course of transducer adaptation in auditory hair cells.
pubmed:affiliation
Department of Physiology, University of Wisconsin Medical School, Madison, Wisconsin 53706, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.