Release of homocysteic acid from rat thalamus following stimulation of somatosensory afferents in vivo: feasibility of glial participation in synaptic transmission.

Details

Serval ID
serval:BIB_5C1B976FD724
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Release of homocysteic acid from rat thalamus following stimulation of somatosensory afferents in vivo: feasibility of glial participation in synaptic transmission.
Journal
Neuroscience
Author(s)
Do K.Q., Benz B., Binns K.E., Eaton S.A., Salt T.E.
ISSN
0306-4522
Publication state
Published
Issued date
2004
Peer-reviewed
Oui
Volume
124
Number
2
Pages
387-393
Language
english
Abstract
The sulphur-containing amino acid homocysteic acid (HCA) is present in and released in vitro from nervous tissue and is a potent neuronal excitant, predominantly activating N-methyl-d-aspartate (NMDA) receptors. However, HCA is localised not in neurones but in glial cells [Eur J Neurosci 3 (1991) 1370], and we have shown that it is released from astrocytes in culture upon glutamate receptor activation [Neuroscience 124 (2004) 377]. We now report the in vivo release of HCA from ventrobasal (VB) thalamus following natural stimulation of somatosensory afferents arising from the facial vibrissae of the rat. Simultaneously with multi-unit recording, [35S]-methionine, a HCA precursor, was perfused through a push-pull cannula in VB thalamus of anaesthetized rats. Perfusates were collected before, during and after 4 min stimulation of the vibrissal afferents with an air jet. A marked release of radiolabeled HCA was observed during and after the stimulation. Furthermore, the beta-adrenoreceptor agonist isoproterenol, which is known to evoke HCA release from glia in vitro, was found to increase the efflux of HCA in the perfusate in vivo. In separate experiments, the excitatory actions of iontophoretically applied HCA on VB neurones were inhibited by the NMDA receptor antagonist CPP, but not by the non-NMDA antagonist CNQX. These results suggest a possible "gliotransmitter" role for HCA in VB thalamus. The release of HCA from glia might exert a direct response or modulate responses to other neurotransmitters in postsynaptic neurons, thus enhancing excitatory processes.
Keywords
6-Cyano-7-nitroquinoxaline-2,3-dione/pharmacology, Action Potentials/drug effects, Animals, Brain Chemistry, Chromatography, High Pressure Liquid/methods, Excitatory Amino Acid Agonists/pharmacology, Excitatory Amino Acid Antagonists/pharmacology, Homocysteine/analogs &amp, derivatives, Homocysteine/metabolism, Iontophoresis/methods, Kainic Acid/pharmacology, Male, Methionine/metabolism, N-Methylaspartate/pharmacology, Neuroglia/metabolism, Physical Stimulation, Piperazines/pharmacology, Rats, Rats, Wistar, Sulfur Isotopes/metabolism, Synaptic Transmission/physiology, Thalamus/metabolism, Vibrissae/innervation
Pubmed
Web of science
Create date
10/03/2008 10:49
Last modification date
20/08/2019 14:14
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