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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
4
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pubmed:dateCreated |
1996-3-5
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pubmed:abstractText |
In order to study the voltage-dependent ion channels in microglia, and their possible modulation by pro-inflammatory substances like lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) we employed the patch-clamp technique on purified rat microglial cell subcultures grown for 1 - 5 days in control condition or after a 24 hour treatment with those agents. Regardless of the culture condition, almost 100% of the cells presented inward-rectifying (IR) K+ currents identified by the following features: (a) extracellular K(+)-dependence of Vrev and whole-cell conductance; (b) inward-rectifying property; (c) channel blocking mechanism by Cs+; and (d) single channel conductance of 27 pS. A 'n' type outward-rectifying (OR) K+ current was present in 30% of the cells during the first 2 days of subcultivation. Its occurrence was strongly dependent on the preparation, varying from 0% to almost 80%, and it decreased to 13% of the cells after three days in culture. It showed the following features: (i) threshold of activation close to -30 mV; (ii) sigmoid current onset; (iii) voltage-dependent kinetics; and (iv) sensitivity to 4-aminopyridine (4-AP) and tetraethylammonium (TEA). Furthermore, we detected two ion currents not previously described in microglia: (i) a slowly activating outward current which appeared at potentials more positive than +20 mV and with a reversal potential close to 0 mV, tentatively identified as a proton current; and (ii) a Cl- conductance identified in ion substitution experiments as the current sensitive to the Cl- channel blocker SITS. The two agents, LPS (20 - 2,000 ng/ml) and IFN-gamma (10 - 100 u/ml), shared the following effects: (a) enhancement of membrane capacitance, and (b) increase of OR current amplitude and frequency of occurrence. Moreover, IFN-gamma was also able to increase IR current density, especially in cells with ameboid morphology, while LPS was ineffective. We conclude that the voltage-dependent ion channel pattern of microglia is more complex than previously thought and that activating agents such as LPS and IFN-gamma share some electrophysiological effects, but differ in others.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Cesium,
http://linkedlifedata.com/resource/pubmed/chemical/Chloride Channels,
http://linkedlifedata.com/resource/pubmed/chemical/Interferon-gamma,
http://linkedlifedata.com/resource/pubmed/chemical/Ion Channels,
http://linkedlifedata.com/resource/pubmed/chemical/Lipopolysaccharides,
http://linkedlifedata.com/resource/pubmed/chemical/Potassium Channels,
http://linkedlifedata.com/resource/pubmed/chemical/Protons
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pubmed:status |
MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
0360-4012
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
1
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pubmed:volume |
42
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
439-51
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pubmed:dateRevised |
2008-11-21
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pubmed:meshHeading |
pubmed-meshheading:8568930-Animals,
pubmed-meshheading:8568930-Biological Transport,
pubmed-meshheading:8568930-Cells, Cultured,
pubmed-meshheading:8568930-Cesium,
pubmed-meshheading:8568930-Chloride Channels,
pubmed-meshheading:8568930-Immunohistochemistry,
pubmed-meshheading:8568930-Interferon-gamma,
pubmed-meshheading:8568930-Ion Channels,
pubmed-meshheading:8568930-Lipopolysaccharides,
pubmed-meshheading:8568930-Microglia,
pubmed-meshheading:8568930-Patch-Clamp Techniques,
pubmed-meshheading:8568930-Potassium Channels,
pubmed-meshheading:8568930-Protons,
pubmed-meshheading:8568930-Rats,
pubmed-meshheading:8568930-Sensitivity and Specificity,
pubmed-meshheading:8568930-Time Factors
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pubmed:year |
1995
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pubmed:articleTitle |
Ion channels in rat microglia and their different sensitivity to lipopolysaccharide and interferon-gamma.
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pubmed:affiliation |
Laboratory of Pathophysiology, Istituto Superiore di Sanitá, Rome, Italy.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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