Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
3
|
| pubmed:dateCreated |
1980-11-25
|
| pubmed:abstractText |
The 42K efflux was measured in voltage clamped sheep Purkinje fibers. The voltage dependence of the K efflux can be described as N-shaped, showing a negative slope region. At potentials negative to -30mV, the K efflux is largely due to K flowing through a channel which rectifies in the inward direction and which is blocked by external application of 20mM Cs+. At potentials positive to -30mV an outward rectifier dominates the shape of the K efflux-voltage relationship. This component is insensitive to short external application of Cs+. Both components were also found when Na+ was replaced by tetramethylammonium. When the steady-state current-voltage relationship is compared with the K efflux one can conclude that the outward rectifying K flux largely determines the shape of this curve at positive membrane potentials, while the negative slope region of the K efflux correlates with the negative slope of the steady-state current-voltage relation. The K efflux is only slightly enhanced by stimulation of the preparation, corroborating the finding of inward-going rectification of the K channel. A clamp program repetitively activating the positive dynamic current e.g. by alternating the membrane potential between -70 and +10mV, increases the K efflux by about 50% as compared to the efflux measured in steady-state at this positive membrane potential. 4-Aminopyridine suppresses both this extra K efflux and the positive dynamic current. It is concluded that K ions contribute to the positive dynamic current.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Apr
|
| pubmed:issn |
0031-6768
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
384
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
207-17
|
| pubmed:dateRevised |
2003-11-14
|
| pubmed:meshHeading |
pubmed-meshheading:6251423-Animals,
pubmed-meshheading:6251423-Cesium,
pubmed-meshheading:6251423-Electric Stimulation,
pubmed-meshheading:6251423-Heart Conduction System,
pubmed-meshheading:6251423-Ion Channels,
pubmed-meshheading:6251423-Kinetics,
pubmed-meshheading:6251423-Membrane Potentials,
pubmed-meshheading:6251423-Potassium,
pubmed-meshheading:6251423-Purkinje Fibers,
pubmed-meshheading:6251423-Sheep
|
| pubmed:year |
1980
|
| pubmed:articleTitle |
K efflux through inward rectifying K channels in voltage clamped Purkinje fibers.
|
| pubmed:publicationType |
Journal Article
|