Linked Life Data

2585554

Source:http://linkedlifedata.com/resource/pubmed/id/2585554

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1989-12-28
pubmed:abstractText
Cochlear outer hair cells have been well established as primary targets of the ototoxic actions of aminoglycoside antibiotics. These cells, isolated from the guinea pig cochlea and maintained in short-term culture, were used as a model for evaluating the acute effects of gentamicin on cell viability, depolarization-induced transmembrane calcium flux, and depolarization-induced motile responses. On the basis of morphology and fluorochromasia, the presence of extracellular gentamicin as high as 5 mM did not affect the viability of the cells for up to 6 hr, the longest time tested. Viable cells showed binding of fluorescently tagged gentamicin to their base but excluded the drug from their cytoplasm. In response to [K+]-depolarization, intracellular calcium levels (monitored with the fluorescent calcium-sensitive dye fluo-3) increased from a resting value of 218 +/- 102 nM to 2,018 +/- 1,077 nM concomitant with a cell shortening of 0.7% +/- 1.3%. The depolarization-induced calcium increase was apparently caused by calcium entry into the cell as it was inhibited by the calcium-channel blocker methoxyverapamil and prevented in the absence of extracellular calcium. Both gentamicin and neomycin blocked the [K+]-induced calcium increase at an IC50 of 50 microM. Despite the inhibition of calcium entry the ability of the outer hair cells to shorten under [K+]-depolarization was not impaired; in fact, cell shortening was even more pronounced in the absence of calcium influx (2.6% +/- 1.4%). This argues effectively against the existence of a calcium-dependent actomyosin-mediated component in [K+]-induced shape changes.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0360-4012
pubmed:author
pubmed:issnType
Print
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
338-46
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Aminoglycoside antibiotics impair calcium entry but not viability and motility in isolated cochlear outer hair cells.
pubmed:affiliation
Kresge Hearing Research Institute, University of Michigan, Ann Arbor 48109-0506.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't