5-Hydroxytryptamine3 receptor modulation of excitatory amino acid release in the rat nucleus tractus solitarius

Neurosci Lett. 1995 May 19;191(1-2):75-8. doi: 10.1016/0304-3940(95)11564-5.


In vivo microdialysis was employed to measure release of endogenous L-glutamate (GLU) and L-aspartate (ASP) in the medial nucleus tractus solitarius of urethane anaesthetised rats. Basal extracellular levels of these amino acids were stable following a 90 min equilibration period (6.3 +/- 0.24 and 3.4 +/- 0.6 pmol/20 microliters sample of GLU and ASP, respectively). Basal levels of endogenous extracellular GLU and ASP were increased over 2-fold and 3-fold, respectively, following local administration of the selective 5-hydroxytryptamine (5-HT3) receptor agonist phenylbiguanide (300 microM). Intracerebral administration of the selective 5-HT3 receptor antagonist ondansetron (30 microM) blocked the effect of phenylbiguanide on GLU release whilst the effect on ASP was variable and complex. These data suggest that 5-HT3 receptor activation in the rat nucleus tractus solitarius can affect excitatory amino acid neurotransmission in this region of the medulla oblongata.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aspartic Acid / metabolism
  • Biguanides / pharmacology
  • Excitatory Amino Acids / metabolism*
  • Excitatory Amino Acids / pharmacology
  • Glutamic Acid / metabolism
  • Hypoglycemic Agents / pharmacology
  • In Vitro Techniques
  • Male
  • Microdialysis
  • Ondansetron / pharmacology
  • Rats
  • Rats, Inbred WKY
  • Receptors, Serotonin / metabolism*
  • Solitary Nucleus / drug effects
  • Solitary Nucleus / metabolism*


  • Biguanides
  • Excitatory Amino Acids
  • Hypoglycemic Agents
  • Receptors, Serotonin
  • Aspartic Acid
  • Glutamic Acid
  • Ondansetron
  • phenyl biguanide