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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:dateCreated |
1984-9-19
|
| pubmed:abstractText |
L cells (a mouse fibroblast cell line) and macrophages have been reported to exhibit slow oscillatory hyperpolarizations and relatively low membrane potentials, when measured with glass micro-electrodes. This paper describes the role of micro-electrode-induced leakage in these oscillations for L cells and a mouse macrophage cell line (P388D1). Both L cells and macrophages showed fast negative-going peak-shaped potential transients upon micro-electrode entry. This shows that the micro-electrode introduces a leakage conductance across the membrane. The peak values of these fast transients were less negative for L cells (-17 mV) than for macrophages (-39 mV), although their sustained resting membrane potentials were about equal (-13 mV). This indicates that the pre-impaled membrane potential of macrophages is more negative than that of L cells. Ionophoretic injection of Ca2+ into the P388D1 macrophages showed the existence of a Ca2+ -dependent hyperpolarizing conductance presumed to be involved in the oscillatory hyperpolarizations of L cells and macrophages. Cells increased in size by X-ray irradiation to reduce membrane input resistances were still found to be susceptible to micro-electrode-induced leakage. Impalement transients upon entry of a second electrode during a hyperpolarization evoked by a first electrode, were often step-shaped instead of peak-shaped due to the high membrane conductance associated with hyperpolarization. Since peak-shaped impalement transients were always seen with the first impalement both in oscillating and non-oscillating cells, oscillatory hyperpolarizations cannot be regarded as spontaneously occurring in the unperturbed cells but are induced by micro-electrode penetration. Since the hyperpolarizing response can be evoked by ionophoretic injection of Ca2+, and oscillatory as well as single hyperpolarizing responses are absent in a Ca2+ -free medium, it is concluded that the Ca2+ needed intracellularly to activate the hyperpolarizing responses enters the cell via the leakage pathway introduced by the measuring electrode.
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| pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-1167564,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-13618265,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-379275,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-381668,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-410816,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-444508,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-4472868,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-5102533,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-512579,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-528572,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-561618,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-6171442,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-6270629,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-6288929,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-6406605,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-6783141,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-6833384,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-7024506,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-7024552,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-7238599,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-7360232,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-811677,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6747902-894703
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| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Jul
|
| pubmed:issn |
0022-3751
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
352
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
625-35
|
| pubmed:dateRevised |
2009-11-18
|
| pubmed:meshHeading |
pubmed-meshheading:6747902-Animals,
pubmed-meshheading:6747902-Calcium,
pubmed-meshheading:6747902-Cell Line,
pubmed-meshheading:6747902-Electric Conductivity,
pubmed-meshheading:6747902-L Cells (Cell Line),
pubmed-meshheading:6747902-Macrophages,
pubmed-meshheading:6747902-Membrane Potentials,
pubmed-meshheading:6747902-Mice,
pubmed-meshheading:6747902-Time Factors
|
| pubmed:year |
1984
|
| pubmed:articleTitle |
Oscillatory hyperpolarizations and resting membrane potentials of mouse fibroblast and macrophage cell lines.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|