Molecular and functional properties of synaptically activated NMDA receptors in neonatal motoneurons in rat spinal cord slices
Language English Country France Media print
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
10762325
DOI
10.1046/j.1460-9568.2000.00989.x
PII: ejn989
Knihovny.cz E-resources
- MeSH
- 6-Cyano-7-nitroquinoxaline-2,3-dione pharmacology MeSH
- Excitatory Amino Acid Antagonists pharmacology MeSH
- Electric Stimulation MeSH
- Electrophysiology MeSH
- Excitatory Postsynaptic Potentials drug effects physiology MeSH
- Magnesium pharmacology MeSH
- Rats MeSH
- Membrane Potentials drug effects physiology MeSH
- Patch-Clamp Techniques MeSH
- Spinal Cord cytology drug effects physiology MeSH
- Motor Neurons drug effects physiology MeSH
- Animals, Newborn physiology MeSH
- Reverse Transcriptase Polymerase Chain Reaction MeSH
- Receptors, N-Methyl-D-Aspartate antagonists & inhibitors genetics physiology MeSH
- Synapses drug effects physiology MeSH
- In Vitro Techniques MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- 6-Cyano-7-nitroquinoxaline-2,3-dione MeSH
- Excitatory Amino Acid Antagonists MeSH
- Magnesium MeSH
- Receptors, N-Methyl-D-Aspartate MeSH
The functional properties of N-methyl-D-aspartate (NMDA) receptor-mediated excitatory postsynaptic currents (EPSC) were studied in fluorescence-labelled motoneurons in thin spinal cord slices. The deactivation of NMDA receptor EPSCs in motoneurons voltage-clamped at +40 mV was independent of intensity or location of stimulation and of postnatal age [taufast = 28.5 +/- 4.6 ms (63.6 +/- 8.8%) and tauslow = 165.6 +/- 49.6 ms]. In the presence of 1 mM Mg2+ the amplitude of NMDA receptor EPSCs was voltage-dependent. Boltzmann analysis of the relationship between peak NMDA receptor EPSC amplitude and membrane potential suggested an apparent Kd of Mg2+ (at 0 mV) of 0.87 mM. Nonstationary variance analysis of NMDA receptor EPSCs gave an estimated single-channel conductance of 59 +/- 14 pS. Direct measurement of the NMDA receptor channel openings in outside-out patches isolated from motoneurons indicated the presence of single-channel conductance levels of 21.8 +/- 2.8 pS, 37. 1 +/- 3.2 pS, 49.6 +/- 5.1 pS and 69.6 +/- 4.2 pS. Single-cell RT-PCR analysis of mRNA revealed that NR1, NR2A-D and NR3A transcripts were expressed in motoneurons. These results suggest that specific assembly of NMDA receptor subunits in motoneurons determines the functional and pharmacological properties of the receptors in these cells.
References provided by Crossref.org
20-oxo-5beta-pregnan-3alpha-yl sulfate is a use-dependent NMDA receptor inhibitor
Axotomy-induced changes in the properties of NMDA receptor channels in rat spinal cord motoneurons
