Oxytocin modulates glutamatergic synaptic transmission between cultured neonatal spinal cord dorsal horn neurons

Young Hwan Jo, Marie Elisabeth Stoeckel, Marie José Freund-Mercier, Rémy Schlichter

Research output: Contribution to journalArticle

72 Scopus citations

Abstract

The functional characteristics of binding sites for the neuropeptide oxytocin (OT) detected by radioautography in laminae I and II of the dorsal horn (DH) and on cultured neonatal DH neurons were studied on the latter using perforated patch-clamp recordings. The neurons were identified by their spike discharge properties and on the basis of the presence of met- enkephalin-like and glutamate decarboxylase-like immunoreactivities. OT (100 nM) never induced any membrane current at a holding potential of -60 mV but increased the frequency of spontaneously occurring AMPA receptor-mediated EPSCs or the mean amplitude of electrically evoked EPSCs in a subset (35%) of neurons. The frequency of miniature EPSCs (m-EPSCs) recorded in the presence of 0.5 μM tetrodotoxin was also increased by OT (100 nM) without any change in their mean amplitude, indicating an action at a site close to the presynaptic terminal. The decay kinetics of any type of EPSC were never modified by OT. The effect of OT was reproduced by [Thr4,Gly7]-OT (100 nM), a selective OT receptor agonist, and blocked by d(CH2)5- [Tyr(Me)2,Thr4,Tyr-NH29]-ornithine vasotocin (100 nM), a specific OT receptor antagonist. Reducing the extracellular Ca2+ concentration from 2.5 to 0.3 mM in the presence of Cd2+ (100 μM) reversibly blocked the effect of OT on m-EPSCs. The OT receptors described here may represent the substrate for modulatory actions of descending hypothalamo-spinal OT-containing pathways on the nociceptive system.

Original languageEnglish (US)
Pages (from-to)2377-2386
Number of pages10
JournalJournal of Neuroscience
Volume18
Issue number7
DOIs
StatePublished - Apr 1 1998

Keywords

  • AMPA receptors
  • Dorsal horn neurons
  • EPSCs
  • GABA
  • Met-enkephalin
  • Nociception
  • Oxytocin
  • Spinal cord

ASJC Scopus subject areas

  • Neuroscience(all)

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