Modulation of primary afferent-mediated neurotransmission and Fos expression by glutamate uptake inhibition in rat spinal neurones in vitro.
Neuropharmacology
; 41(5): 582-91, 2001 Oct.
Article
em En
| MEDLINE
| ID: mdl-11587713
ABSTRACT
The effect of altered endogenous levels of synaptic glutamate on neurotransmission and synaptic dorsal horn Fos expression was determined in rat spinal cord in vitro. The uptake inhibitor L-trans-pyrrolidine-2,4-dicarboxylate (L-PDC, 1mM) was tested against dorsal root-ventral root potentials (DR-VRP), afferent-mediated slow dorsal horn excitatory postsynaptic potentials (DR-EPSP) and nociceptive afferent-induced synaptic currents (EPSCs) of substantia gelatinosa neurones. L-PDC reduced DR-VRP fast and slow peak amplitude and duration (P<0.05), slow DR-EPSP amplitude and duration (P<0.005) and EPSC amplitude (P<0.05). The Group II/III mGluR antagonist (RS)-alpha-cyclopropyl-4-phosphonophenylglycine (CPPG, 100 microM) reduced L-PDC inhibition of synaptic potentials. The Group II antagonist (2S)-2-amino-2-(1S,2S-2-carboxycycloprop-1-yl)-3-(xanth-9-yl)propanoic acid (LY341495, 300 nM) and the Group III antagonist (RS)-alpha-methylserine-O-phosphate (MSOP, 10 microM) partially reversed EPSC inhibition by L-PDC. The Group III agonist L(+)-2-amino-4-phosphonobutyric acid (L-AP4, 30 microM) mimicked CPPG-sensitive inhibitory effects of L-PDC on DR-VRP (P<0.001) and the slow DR-EPSP (P<0.005). L-PDC (1mM) or L-AP4 (30 microM) reduced afferent-evoked dorsal horn Fos expression, this effect was reversed by CPPG. These data suggest that increased synaptic glutamate levels may activate inhibitory Group II/III mGluR receptors and impact significantly on nociceptive neurotransmission and transcriptional adaptive responses of target neurones.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vias Aferentes
/
Proteínas Proto-Oncogênicas c-fos
/
Inibidores da Captação de Neurotransmissores
/
Ácido Glutâmico
/
Células do Corno Posterior
/
Glicina
Limite:
Animals
Idioma:
En
Revista:
Neuropharmacology
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Reino Unido