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Endogenously released 5-HT inhibits A and C fiber-evoked synaptic transmission in the rat spinal cord by the facilitation of GABA/glycine and 5-HT release via 5-HT2A and 5-HT3 receptors
Title: | Endogenously released 5-HT inhibits A and C fiber-evoked synaptic transmission in the rat spinal cord by the facilitation of GABA/glycine and 5-HT release via 5-HT2A and 5-HT3 receptors |
Authors: | Iwasaki, Takeyuki Browse this author | Otsuguro, Ken-ichi Browse this author →KAKEN DB | Kobayashi, Takeshi Browse this author | Ohta, Toshio Browse this author →KAKEN DB | Ito, Shigeo Browse this author →KAKEN DB |
Keywords: | 5-HT | Spinal reflex potential | GABA | Glycine | Autoreceptor |
Issue Date: | 28-Feb-2013 |
Publisher: | Elsevier |
Journal Title: | European Journal of Pharmacology |
Volume: | 702 |
Issue: | 1-3 |
Start Page: | 149 |
End Page: | 157 |
Publisher DOI: | 10.1016/j.ejphar.2013.01.058 |
PMID: | 23399761 |
Abstract: | Serotonin (5-HT) released from descending fibers plays important roles in spinal functions such as locomotion and nociception. 5-HT2A and 5-HT3 receptors are suggested to contribute to spinal antinociception, although their activation also contributes to neuronal excitation. In the neonatal spinal cord, DL-p-chloroamphetamine (pCA), a 5-HT releaser, inhibited both A fiber-evoked monosynaptic reflex potential (MSR) and C fiber-evoked slow ventral root potential (sVRP). The pCA-mediated inhibition was reversed by ketanserin (a 5-HT2A receptor antagonist) and tropisetron (a 5-HT3 receptor antagonist). Bath-applied 5-HT also inhibited MSR and sVRP; in this case, the actions of 5-HT were antagonized by ketanserin, but not by tropisetron. The pCA-evoked inhibition of sVRP was reduced by bicuculline (a GABA(A) receptor antagonist) and strychnine (a glycine receptor antagonist). Furthermore, ketanserin inhibited the pCA-evoked release of gamma-aminobutyric acid (GABA) and glycine, while tropisetron inhibited the pCA-evoked release of 5-HT. These results suggest that 5-HT released by pCA activates 5-HT2A receptors, which in turn stimulates the release of GABA/glycine and thereby blocks the spinal nociceptive pathway. 5-HT3 receptors may be involved in the facilitation of 5-HT release via a positive feedback process. (C) 2013 Elsevier B.V. All rights reserved. |
Relation: | http://www.sciencedirect.com/science/article/pii/S0014299913000782 |
Type: | article (author version) |
URI: | http://hdl.handle.net/2115/52751 |
Appears in Collections: | 獣医学院・獣医学研究院 (Graduate School of Veterinary Medicine / Faculty of Veterinary Medicine) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 乙黒 兼一
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