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GABAergic modulation of serotonin release in the rat subfornical organ area.
- Source :
-
Neuroscience letters [Neurosci Lett] 2016 Sep 06; Vol. 630, pp. 114-119. Date of Electronic Publication: 2016 Jul 21. - Publication Year :
- 2016
-
Abstract
- The present study was carried out to examine whether γ-aminobutyric acid (GABA) receptor mechanisms are involved in the release of serotonin (5-hydroxytryptamine, 5-HT) in the subfornical organ (SFO) using intracerebral microdialysis techniques. Perfusion with the GABA receptor antagonists as well as agonists was performed in the region of the SFO through a microdialysis probe and extracellular concentrations of 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) were measured in freely moving rats. Perfusion with the GABAA receptor antagonist bicuculline (10 and 50μM), but not the GABAB receptor antagonist phaclofen (10 and 50μM), increased dialysate 5-HT and 5-HIAA concentrations in the SFO area, suggesting that the GABAergic system may tonically inhibit the 5-HT release in the SFO area through GABAA receptors. Higher perfusion with the GABAA receptor agonist muscimol (50μM) or the GABAB receptor agonist baclofen (250μM) decreased extracellular levels of 5-HT and 5-HIAA in the SFO area. Nonhypotensive hypovolemia induced by subcutaneous injection of polyethylene glycol (PEG, 30%, 5ml) significantly enhanced the 5-HT and 5-HIAA concentrations in the SFO area. The enhanced 5-HT and 5-HIAA levels elicited the PEG treatment were reduced by perfusion with muscimol (10μM), but not by baclofen (50μM). These results show the involvement of both GABAA and GABAB receptors in the modulation of the 5-HT release in the SFO area, and imply that the GABAA receptor mechanism may be importance for the serotonergic regulatory system of body fluid balance.<br /> (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)
- Subjects :
- Animals
Baclofen administration & dosage
Baclofen analogs & derivatives
Bicuculline administration & dosage
GABA-A Receptor Agonists administration & dosage
GABA-A Receptor Antagonists administration & dosage
GABA-B Receptor Agonists administration & dosage
GABA-B Receptor Antagonists administration & dosage
Hydroxyindoleacetic Acid metabolism
Male
Muscimol administration & dosage
Rats
Rats, Wistar
Receptors, GABA-A metabolism
Receptors, GABA-B metabolism
Serotonin metabolism
Subfornical Organ metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1872-7972
- Volume :
- 630
- Database :
- MEDLINE
- Journal :
- Neuroscience letters
- Publication Type :
- Academic Journal
- Accession number :
- 27453060
- Full Text :
- https://doi.org/10.1016/j.neulet.2016.07.040