Linked Life Data

11833609

Source:http://linkedlifedata.com/resource/pubmed/id/11833609

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2002-2-8
pubmed:abstractText
In mammals, sound transduction by inner hair cells (IHC) generates a receptor potential whose amplitude and phase drive auditory nerve firing. The membrane filter properties that define the input-output function of IHC are derived from membrane conductance and capacitance. These elements of the membrane filter were quantified using whole-cell voltage clamp of IHC from the four turns of the guinea pig cochlea. IHC membrane properties were remarkably constant along the cochlea, in contrast with all other auditory hair cell systems, and suggests that extrinsic processes such as the active filter provided by the outer hair cells are matched to a constant transfer function of the IHC. Two outwardly rectifying K+ currents contribute to the IHC membrane conductance. These combined currents activate at approximately -55 mV. IHC mean input resistance was 140 M ohm and capacitance was 10.0 pF, generating a membrane time constant of 1.4 ms or a corner frequency of approximately 115 Hz, which is consistent with reported low-frequency roll-off of the IHC AC receptor potential in vivo. Approximately 40% of the 313-1 nS total K+ conductance about 0 mV was attributed to charybdotoxin-sensitive K(Ca) channels (also sensitive to cell dialysis with the Ca2+ chelator BAPTA or removal of extracellular Ca2+). The only known ligand-activated conductance in mature IHC, the P2X receptor conductance, averaged 31 nS (activated by 400 microM ATP; about -75 mV) irrespective of cell origin. Thus, regulation of intracellular Ca2+ and activation of P2X receptors by extracellular ATP provide capacity for local dynamic fine-tuning of the IHC membrane filter.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1525-3961
pubmed:author
pubmed:issnType
Print
pubmed:volume
2
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
362-76
pubmed:dateRevised
2011-10-26
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Positional analysis of guinea pig inner hair cell membrane conductances: implications for regulation of the membrane filter.
pubmed:affiliation
Physiology Division, Faculty of Medical and Health Sciences, University of Auckland, New Zealand.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't