Linked Life Data

2415917

Source:http://linkedlifedata.com/resource/pubmed/id/2415917

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1986-1-6
pubmed:abstractText
The fluctuations in transepithelial current through the abdominal skin of bullfrogs (Rana catesbeiana) were analysed while the transepithelial voltage was clamped to zero. A Lorentzian component in the power spectrum was recorded when the skin was bathed with Ca2+ free NaCl Ringer's on both sides. After replacement of all mucosal Na+ by choline the Lorentzian component disappeared. The application of mucosa positive potentials enhanced the plateau of the relaxation noise component while it was depressed by mucosa negative potentials. These observations showed that the current associated with the relaxation noise, was carried by Na+ moving in the inward direction. Divalent cations added to the mucosal solution in micromolar concentrations depressed the relaxation noise immediately, which is indicative for an apical localization of the fluctuating channels. The relaxation noise depended strongly on the pH of the mucosal medium: alkalinization enhanced the relaxation noise while acidification depressed the fluctuations. Micromolar concentrations of the diuretic amiloride, which is known to block the Na+ entry into the cellular compartment, enhanced the Na+-dependent relaxation noise while at higher concentrations an inhibitory effect was observed. From these observations it was concluded that the relaxation noise is caused by inward Na+ movement through fluctuating channels which are localized in the apical membrane. These channels seem to constitute a pathway in parallel with the amiloride-blockable channels. Ionic substitution of Na+ by other monovalent cations showed that these channels are also permeable for K+, Rb+, NH4+, Cs+ and Tl+, but not for Li+. Divalent cations in micromolar concentrations completely occlude these fluctuating channels. Therefore, this pathway will be blocked for monovalent cations when normal Ca2+ containing Ringer's are used as mucosal bathing medium.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0031-6768
pubmed:author
pubmed:issnType
Print
pubmed:volume
405
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
250-9
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Ca2+-sensitive, spontaneously fluctuating, cation channels in the apical membrane of the adult frog skin epithelium.
pubmed:publicationType
Journal Article