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Distinct synaptic and extrasynaptic NMDA receptors identified in dorsal horn neurones of the adult rat spinal cord
Author(s) -
Momiyama Akiko
Publication year - 2000
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.2000.t01-1-00621.x
Subject(s) - ifenprodil , nmda receptor , neuroscience , spinal cord , glutamate receptor , chemistry , patch clamp , receptor , nociception , protein subunit , biophysics , electrophysiology , biology , biochemistry , gene
1 N‐ methyl‐D‐aspartate receptors (NMDARs) were examined in substantia gelatinosa (SG) neurones of adult rat spinal cord slices. 2 In somatic outside‐out patches, high‐ and low‐conductance NMDAR channels were present. The low‐conductance channels exhibited asymmetrical transitions between the main (44 pS) and subconductance (19 pS) levels, suggesting that they arise from NR2D subunit‐containing receptors. The high‐conductance channels (main conductance, 57 pS) were blocked by ifenprodil, an NR2B subunit selective blocker. 3 Ifenprodil had no effect on NMDA‐EPSCs. The double‐exponential decay time course and the apparent K d for Mg 2+ of NMDA‐EPSCs suggested the expression of NR2A subunit‐containing receptors at the synapse. 4 These results indicate that different NMDAR subtypes are expressed in subsynaptic and extrasynaptic regions of adult SG neurones, which may have differential roles in nociception.