5-Hydroxytryptamine-3 receptors modulate synaptic activity in the rat nucleus tractus solitarius in vitro

Steven R. Glaum*, Penelope A. Brooks, K. Michael Spyer, Richard J. Miller

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

52 Scopus citations

Abstract

Whole-cell patch clamp recordings were made from neurons in the rat nucleus tractus solitarius (NTS) in transverse brainstem slices. 5-Hydroxytryptamine (5-HT, 100 μM) and the selective 5-HT3 receptor agonist 2-methyl-5-HT (2-CH3-5-HT, 100 μM) depolarized 86% of NTS neurons at resting membrane potential (Vm). This response was resistant to tetrodotoxin (TTX) and Co2+ application. In addition, 2-CH3-5-HT (500 nM-100 μM) increased the amplitude and frequency of both excitatory and inhibitory spontaneous synaptic potentials. This effect was also TTX-resistant, but was abolished by Co2+. The effects of 2-CH3-5-HT on EPSPs and IPSPs evoked by electrical stimulation of the tractus solitarius (TS) were analyzed separately in the presence of bicuculline or 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), respectively. Concentrations of 2-CH3-5-HT between 500 nM and 1 μM decreased the amplitude of evoked EPSPs and IPSPs with similar potency. The selective 5-HT3 receptor antagonists ICS 205-930 (10 nM) and MDL 72222 (10 μM) reversibly blocked the effects of 2-CH3-5-HT at all doses examined. It is concluded that 5-HT3 receptors can mediate both pre- and postsynaptic responses in the NTS.

Original languageEnglish (US)
Pages (from-to)62-68
Number of pages7
JournalBrain research
Volume589
Issue number1
DOIs
StatePublished - Aug 28 1992

Keywords

  • Brain slice
  • Medulla oblongata
  • Nucleus tractus solitarii
  • Patch clamp
  • Serotonin
  • Serotonin

ASJC Scopus subject areas

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

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