Actions of endomorphins on synaptic transmission of Aδ-fibers in spinal cord dorsal horn neurons

Yoichi Yajiri, Li-Yen Huang

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The effects of endogenous μ-opioid ligands, endomorphins, on Aδ- afferent-evoked excitatory postsynaptic currents (EPSCs) were studied in substantia gelatinosa neurons in spinal cord slices. Under voltage-clamp conditions, endomorphins blocked the evoked EPSCs in a dose-dependent manner. To determine if the block resulted from changes in transmitter release from glutamatergic synaptic terminals, the opioid actions on miniature excitatory postsynaptic currents (mEPSCs) were examined. Endomorphins (1 μM) reduced the frequency but not the amplitude of mEPSCs, suggesting that endomorphins directly act on presynaptic terminals. The effects of endomorphins on the unitary (quantal) properties of the evoked EPSCs were also studied. Endomorphins reduced unitary content without significantly changing unitary amplitude. These results suggest that in addition to presynaptic actions on interneurons, endomorphins also inhibit evoked EPSCs by reducing transmitter release from Aδ-afferent terminals. Copyright (C) 2000 National Science Council.

Original languageEnglish (US)
Pages (from-to)226-231
Number of pages6
JournalJournal of Biomedical Science
Volume7
Issue number3
StatePublished - May 2000

Fingerprint

Posterior Horn Cells
Myelinated Nerve Fibers
Excitatory Postsynaptic Potentials
Synaptic Transmission
Opioid Analgesics
Neurons
Transmitters
Fibers
Clamping devices
Presynaptic Terminals
Ligands
Electric potential
Substantia Gelatinosa
Interneurons
Spinal Cord Dorsal Horn
Spinal Cord

Keywords

  • μ-Opioid
  • Dorsal horn
  • Endomorphin
  • Nociceptive neurons
  • Spinal cord
  • Substantia gelatinosa

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

Cite this

Actions of endomorphins on synaptic transmission of Aδ-fibers in spinal cord dorsal horn neurons. / Yajiri, Yoichi; Huang, Li-Yen.

In: Journal of Biomedical Science, Vol. 7, No. 3, 05.2000, p. 226-231.

Research output: Contribution to journalArticle

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