Linked Life Data

7666365

Source:http://linkedlifedata.com/resource/pubmed/id/7666365

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1995-10-10
pubmed:abstractText
1. Simultaneous fluorescence and whole-cell current measurements using the calcium indicator dye fura-2 were made in HEK 293 cells expressing recombinant glutamate receptor (GluR) channels, and fractional Ca2+ currents (the proportion of whole-cell current carried by Ca2+; Pf) were determined. 2. Cells expressing N-methyl-D-aspartate receptor (NMDAR) channels showed glutamate activated Ca2+ inflow in the voltage range -60 to 40 mV in normal extracellular solution. Ca2+ inflow decreased in a voltage-dependent manner at membrane potentials more negative than -30 mV due to Mg2+ block. Voltage dependence of block at negative potentials was stronger in cells expressing the NR1-NR2A as compared with cells expressing NR1-NR2C subunits. 3. Fractional Ca2+ currents through NMDARs were independent of extracellular Mg2+ and varied between 8.2% (NR1-NR2C subunits) and 11% (NR1-NR2A subunits) in normal extracellular solution (1.8 mM Ca2+) at -60 mV membrane potential. Pf values increased with increasing [Ca2+]o in the range of 0.5-10mM [Ca2+]o in a saturating fashion. 4. In cells expressing alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptor (AMPAR) subunits which were unedited at the Q/R site of the putative transmembrane segment TM2 (Q-form), or in cells coexpressing unedited and edited subunits (R-form), the glutamate-evoked Ca2+ inflow increased from 20 to -80 mV in an almost linear way. 5. Fractional Ca2+ currents through AMPAR channels depended on subunit composition. Pf values of Q-form homomeric channels at -60 mV and 1.8 mM [Ca2+]o were between 3.2 and 3.9%. They were slightly voltage dependent and increased with [Ca2+]o in the range 1.8-10mM. Pf values in cells co-expressing Q- and R-form subunits were almost one order of magnitude smaller (0.54%). 6. Relative concentrations of Q-form and R-form GluR-B subunit-specific cDNAs used for cell transfection determined the expression of functionally different heteromeric AMPARS. Pf decreased with increasing relative concentration of R-form encoding CDNAs from 3.4 to 1.4%, demonstrating that editing of the Q/R site of GluR-B subunits decreases Ca2+ inflow through heteromeric AMPARs. 7. Cells expressing the GluR-6 subunit of the kainate receptor (KAR) family were characterized by Pf values which depended on the editing in the TM1 and TM2 segments. Pf values were largest for the Q-form (1.55-2.0%) and lowest for R-form channels (< 0.2%), suggesting that Q/R site editing also decreases Ca2+ inflow through KAR channels. Cells co-expressing both subunit forms showed an intermediate value (0.58%).(ABSTRACT TRUNCATED AT 400 WORDS)
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-1282929, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-1326045, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-1331424, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-1370372, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-1382314, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-1697342, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-1699275, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-1709304, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-1834949, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-2155495, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-2167544, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-2451020, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-2457089, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-2543272, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-2856092, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-3838314, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-6270629, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-6325946, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-7510879, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-7512349, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-7545230, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-7678465, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-7681676, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-7687849, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-8011338, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-8094038, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-8265592, http://linkedlifedata.com/resource/pubmed/commentcorrection/7666365-8396474
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0022-3751
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
485 ( Pt 2)
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
403-18
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Fractional calcium currents through recombinant GluR channels of the NMDA, AMPA and kainate receptor subtypes.
pubmed:affiliation
Max-Planck-Institut für medizinische Forschung, Abteilung Zellphysiologie, Heidelberg, Germany.
pubmed:publicationType
Journal Article