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rdf:type |
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lifeskim:mentions |
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pubmed:dateCreated |
2000-8-21
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pubmed:abstractText |
We investigated the types and distribution of voltage-gated K+ channels in the soma and apical dendrite of layer 5 (L5) neocortical pyramidal neurones, of young rats (postnatal days 13-15), in acute brain slices. A slow inactivating outward K+ current and a fast inactivating outward K+ current were detected in nucleated patches. The slow K+ current was completely blocked by tetraethylammonium (TEA) with an IC50 of 5 +/- 1 mM (mean +/- s.e.m.) and was partially blocked by 4-aminopyridine (4-AP). The fast K+ current was blocked by 4-AP with an IC50 of 4.2 +/- 0.5 mM, but was not blocked by TEA. The activation kinetics of the slow K+ current were described by a second order Hodgkin-Huxley model. The slow K+ current displayed bi-exponential inactivation. A fourth order Hodgkin-Huxley model for activation and first order for inactivation described the kinetics of the fast K+ current. In somatic cell-attached recordings, three classes of single K+ channels could be differentiated based on their unitary conductance and inactivation kinetics, a fast inactivating channel having a conductance of 13 +/- 1 pS, a slow inactivating channel having a conductance of 9.5 +/- 0.5 pS, and a very slowly inactivating channel having a conductance of 16 +/- 1 pS. The inactivation time constants of the slow and of the very slow K+ channel corresponded to the two inactivation time constants of the slow K+ current observed in nucleated patches. This suggested that two distinct K+ channels mediated the slow K+ current in nucleated patches. The three subtypes of K+ channels that were observed in somatic recordings were present along the apical dendrite. The amplitude of ensemble K+ currents in cell-attached patches decreased along the apical dendrite as the distance from the soma increased, with a slope of -0.9 +/- 0.3 pA per 100 microm. The results suggest that the decrease of the voltage-gated K+ channel density from the soma along the apical dendrite of L5 pyramidal neurones helps to define a distal, low threshold region for the initiation of dendritic regenerative potentials.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/10856117-10192334,
http://linkedlifedata.com/resource/pubmed/commentcorrection/10856117-10634854,
http://linkedlifedata.com/resource/pubmed/commentcorrection/10856117-12991237,
http://linkedlifedata.com/resource/pubmed/commentcorrection/10856117-1359126,
http://linkedlifedata.com/resource/pubmed/commentcorrection/10856117-1528115,
http://linkedlifedata.com/resource/pubmed/commentcorrection/10856117-1668364,
http://linkedlifedata.com/resource/pubmed/commentcorrection/10856117-1908562,
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http://linkedlifedata.com/resource/pubmed/commentcorrection/10856117-2348860,
http://linkedlifedata.com/resource/pubmed/commentcorrection/10856117-2456612,
http://linkedlifedata.com/resource/pubmed/commentcorrection/10856117-3059497,
http://linkedlifedata.com/resource/pubmed/commentcorrection/10856117-7500154,
http://linkedlifedata.com/resource/pubmed/commentcorrection/10856117-7623158,
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http://linkedlifedata.com/resource/pubmed/commentcorrection/10856117-9689126
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Jun
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pubmed:issn |
0022-3751
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
15
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pubmed:volume |
525 Pt 3
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
621-39
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:10856117-4-Aminopyridine,
pubmed-meshheading:10856117-Age Factors,
pubmed-meshheading:10856117-Animals,
pubmed-meshheading:10856117-Dendrites,
pubmed-meshheading:10856117-Electric Stimulation,
pubmed-meshheading:10856117-Ion Channel Gating,
pubmed-meshheading:10856117-Membrane Potentials,
pubmed-meshheading:10856117-Patch-Clamp Techniques,
pubmed-meshheading:10856117-Potassium,
pubmed-meshheading:10856117-Potassium Channels,
pubmed-meshheading:10856117-Pyramidal Cells,
pubmed-meshheading:10856117-Rats,
pubmed-meshheading:10856117-Rats, Wistar,
pubmed-meshheading:10856117-Somatosensory Cortex,
pubmed-meshheading:10856117-Tetraethylammonium,
pubmed-meshheading:10856117-Tetrodotoxin
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pubmed:year |
2000
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pubmed:articleTitle |
Voltage-gated K+ channels in layer 5 neocortical pyramidal neurones from young rats: subtypes and gradients.
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pubmed:affiliation |
Abteilung Zellphysiologie, Max-Planck-Institut für Medizinische Forschung, Jahnstrasse 29, D-69120 Heidelberg, Germany. alon.mpimf-heidelberg.mpg.de
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pubmed:publicationType |
Journal Article,
In Vitro
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