Effects of steroids on NMDA receptors and excitatory synaptic transmission 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
11553299
DOI
10.1046/j.0953-816x.2001.01663.x
PII: ejn1663
Knihovny.cz E-resources
- MeSH
- Algorithms MeSH
- Electrophysiology MeSH
- Excitatory Postsynaptic Potentials drug effects MeSH
- Rats MeSH
- Patch-Clamp Techniques MeSH
- Spinal Cord cytology drug effects physiology MeSH
- Motor Neurons drug effects MeSH
- Synaptic Transmission drug effects MeSH
- Animals, Newborn physiology MeSH
- Rats, Wistar MeSH
- Receptors, N-Methyl-D-Aspartate antagonists & inhibitors MeSH
- Steroids pharmacology 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
- Receptors, N-Methyl-D-Aspartate MeSH
- Steroids MeSH
The effect of steroids on NMDA receptors and excitatory postsynaptic transmission was studied in fluorescence-labelled motoneurons in thin spinal cord slices. In outside-out patches, NMDA-induced responses were potentiated by 79% in the presence of 20-oxopregn-5-en-3beta-yl sulfate (PS), while in the presence of 20-oxo-5alpha-pregnan-3alpha-yl sulfate (3alpha5alphaS) and 20-oxo-5beta-pregnan-3alpha-yl sulfate (3alpha5betaS) they were diminished by 57% and 66%, respectively. PS and 3alpha5betaS had no effect on the amplitude of single NMDA receptor channel openings, however, both compounds altered relative distribution of the openings to individual conductance levels. In control cases, the most frequent openings of the NMDA receptor channels were at the 70 pS conductance level, while in the presence of PS or 3alpha5betaS, the most frequent openings were at the 55 pS conductance level. Analysis of the mean current transferred by NMDA receptor channel openings at individual conductance levels indicated that in the presence of PS, the mean current induced by 55 pS conductance openings was significantly increased. In the presence of 3alpha5betaS, the mean currents induced by 55 pS and 70 pS conductance openings were significantly decreased. The amplitude of NMDA receptor-mediated EPSCs was potentiated by 54% in the presence of PS and the deactivation kinetics slowed. Neither the amplitude nor the kinetics of NMDA receptor-mediated EPSCs was significantly changed in the presence of 3alpha5betaS. The results of our experiments indicate that neurosteroids affect NMDA receptors in motoneurons. The effect appears to be influenced by the receptor subunit composition.
References provided by Crossref.org
20-oxo-5beta-pregnan-3alpha-yl sulfate is a use-dependent NMDA receptor inhibitor
Molecular mechanism of pregnenolone sulfate action at NR1/NR2B receptors
