Presynaptic suppression of excitatory postsynaptic potentials in rat ventral horn neurons by muscarinic agonists

Z. G. Jiang, N. J. Dun

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In addition to depolarizing the ventral horn cells including antidromically identified motoneurons in thin transverse neonatal rat spinal cord slice preparations, exogenously applied acetylcholine (ACh) suppressed the amplitude of excitatory postsynaptic potentials (EPSPs) either occurring spontaneously or elicited by stimulation of dorsal rootlets. A reduction of EPSPs could still be detected when the ACh-induced depolarization was nullified by hyperpolarizing current. Atropine but not d-tubocurarine effectively antagonized the depolarization and synaptic depression caused by ACh. While depressing the EPSPs, ACh had no appreciable effect on membrane depolarizations elicited by glutamate. Methacholine mimicked the depolarizing and synaptic depressant effects of ACh. The results suggest that muscarinic agonists inhibit synaptic transmission of ventral horn neurons including motoneurons by a presynaptic mechanism in reducing the output of excitatory transmitters.

Original languageEnglish (US)
Pages (from-to)182-186
Number of pages5
JournalBrain research
Issue number1
StatePublished - Aug 27 1986



  • motoneuron
  • muscarinic agonist
  • presynaptic inhibition
  • ventral horn neuron

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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