Glutamate modulates neurotransmission in the submucosal plexus of guinea-pig small intestine

Neuroreport. 1999 Sep 29;10(14):3045-8. doi: 10.1097/00001756-199909290-00031.


Effects of glutamate on synaptic transmission in the submucosal plexus of guinea-pig small intestine were studied with intracellular electrophysiological recording methods. Glutamate suppressed stimulus-evoked slow excitatory postsynaptic potentials (EPSPs) and increased the amplitude of slow inhibitory postsynaptic potentials (IPSPs) in submucosal neurons. The actions of glutamate were mimicked by the group I metabotropic glutamate receptor (mGluRs) agonist DHPG, but not by the group II agonist S-4C3HPG, the group III agonist L-AP4, or selective agonists for ionotropic glutamate receptors (iGluRs). Glutamate actions were suppressed by the selective group I mGluRs antagonist S-4CPG, but not by group II and III mGluRs antagonist CPPG or iGluRs antagonists. Glutamate suppressed substance P- and 5-HT-evoked slow EPSP-like responses and potentiated norepinephrine-induced slow IPSP-like responses. The results suggest that group I mGluRs mediate glutamate-induced suppression of slow EPSPs and potentiation of slow IPSPs in S-type uniaxonal submucosal neurons.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Excitatory Amino Acid Agonists / pharmacology
  • Excitatory Amino Acid Antagonists / pharmacology
  • Excitatory Postsynaptic Potentials / physiology
  • Glutamic Acid / physiology*
  • Guinea Pigs
  • In Vitro Techniques
  • Intestinal Mucosa / innervation*
  • Intestine, Small / innervation*
  • Male
  • Receptors, Metabotropic Glutamate / agonists
  • Receptors, Metabotropic Glutamate / antagonists & inhibitors
  • Synaptic Transmission / physiology*


  • Excitatory Amino Acid Agonists
  • Excitatory Amino Acid Antagonists
  • Receptors, Metabotropic Glutamate
  • Glutamic Acid