Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
1 Pt 2
|
| pubmed:dateCreated |
1988-2-25
|
| pubmed:abstractText |
The basolateral membrane of the rabbit proximal convoluted tubule (PCT) is known to be largely permeable to K ions. The patch-clamp technique was used to investigate the molecular basis of this K permeability. At room temperature and with a high-K solution (127 mM) in both the bathing medium and the patch pipette, current jumps associated with an inward-rectifying channel could be detected in every active cell-attached experiment. When the K concentration in the pipette was changed from 200 to 5 mM KCl (NaCl replacement), the single-channel conductance for inward currents changed from 54 to 10 pS. The observed shift in the zero current potential measured as a function of the patch pipette K concentration could be fitted using the Goldman-Hodgkin-Katz equation with a permeability ratio PNa/PK = 0.06. The channel was found to be moderately voltage dependent (e-fold per 56 mV depolarization). For instance, the open-channel probability (Po) increased from 0.06 to 0.16 following a membrane depolarization from -50 to +50 mV. A time interval distribution analysis showed for the open state a dominant single time constant of 14 and 10 ms at 50 and -50 mV, respectively. Two time constants equal to 1 (flickering) and 26 ms at +50 mV and to 0.6 and 300 ms at -50 mV were obtained for the closed-state interval distribution. Based on this analysis, it was concluded that the decrease of Po at negative potentials was due more to the appearance of prolonged silent periods than from a change in the channel mean open time.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Jan
|
| pubmed:issn |
0002-9513
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
254
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
F105-13
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:2447800-Algorithms,
pubmed-meshheading:2447800-Animals,
pubmed-meshheading:2447800-Basement Membrane,
pubmed-meshheading:2447800-Electric Conductivity,
pubmed-meshheading:2447800-Electrophysiology,
pubmed-meshheading:2447800-Ion Channels,
pubmed-meshheading:2447800-Kidney Tubules, Proximal,
pubmed-meshheading:2447800-Membrane Potentials,
pubmed-meshheading:2447800-Potassium,
pubmed-meshheading:2447800-Rabbits
|
| pubmed:year |
1988
|
| pubmed:articleTitle |
Single-channel analysis of a K channel at basolateral membrane of rabbit proximal convoluted tubule.
|
| pubmed:affiliation |
Membrane Transport Research Group, University of Montreal, Quebec, Canada.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|