Feedback stimulation of somatodendritic serotonin release: A 5-HT3 receptor-mediated effect in the raphe nuclei of the rat

Erzsebet Bagdy, Sandor Solyom, L. Hársing

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

Slices from rat midbrain containing the raphe nuclei and from hippocampus were prepared, loaded with [3H]5-HT and superfused and the resting and the electrically stimulated [3H]5-HT release was measured. The 5-HT3 receptor agonist 2-methyl-5-HT (1 to 10 μmol/l) increased the resting tritium outflow in superfused raphe nuclei slices, EC50 5.3 μmol/l. The 2- methyl-5-HT-induced increase of tritium outflow was an external Ca2+- independent process and was not altered by reserpine pretreatment but it was reversed by addition of the 5-HT uptake inhibitor fluoxetine (1 mmol/l). The 5-HT3 receptor antagonists ondansetron and GYKI-46 903 (1 μmol/l) did not antagonize the stimulatory effect of 2-methyl-5-HT on resting tritium outflow. 2-Methyl-5-HT in lower concentration increased the electrically induced tritium overflow from raphe nuclei slices (EC50 0.56 μmol/l) and also from hippocampal slices preloaded with [3H]5-HT. These effects were reversed by 1 μmol/l of ondansetron and GYKI-46903. The 5-HT3 receptor antagonists (1 μmol/l) were without effects on depolarization-evoked [3H]5- HT release at 2 Hz stimulation, when 10 Hz stimulation was used, ondansetron and GYKI-46 903 reduced the tritium overflow from raphe nuclei slices. These data indicate that 5-HT3 receptors positively alter depolarization-induced somatodendritic 5-HT release in the raphe nuclei. They also show that 2- methyl-5-HT is able to evoke 5-HT release not only from vesicles but also from cytoplasmic stores via a transporter-dependent exchange process.

Original languageEnglish
Pages (from-to)203-208
Number of pages6
JournalBrain Research Bulletin
Volume45
Issue number2
DOIs
Publication statusPublished - 1998

Fingerprint

Receptors, Serotonin, 5-HT3
Raphe Nuclei
Tritium
Serotonin
Ondansetron
Serotonin 5-HT3 Receptor Antagonists
Serotonin 5-HT3 Receptor Agonists
Cytoplasmic Vesicles
Fluoxetine
Reserpine
Serotonin Uptake Inhibitors
Hippocampus
2-methyl-5-HT

Keywords

  • 2-Methyl-5- HT
  • 5-HT receptors
  • GYKI-46 903
  • Ondansetron
  • Raphe nuclei slices
  • Serotonin release

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Feedback stimulation of somatodendritic serotonin release : A 5-HT3 receptor-mediated effect in the raphe nuclei of the rat. / Bagdy, Erzsebet; Solyom, Sandor; Hársing, L.

In: Brain Research Bulletin, Vol. 45, No. 2, 1998, p. 203-208.

Research output: Contribution to journalArticle

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