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Titolo:
Activation of presynaptic group III metabotropic receptors enhances glutamate release in rat entorhinal cortex
Autore:
Evans, DI; Jones, RSG; Woodhall, G;
Indirizzi:
Univ Bristol, Sch Med Sci, Dept Physiol, Bristol BS8 1TD, Avon, England Univ Bristol Bristol Avon England BS8 1TD Bristol BS8 1TD, Avon, England
Titolo Testata:
JOURNAL OF NEUROPHYSIOLOGY
fascicolo: 5, volume: 83, anno: 2000,
pagine: 2519 - 2525
SICI:
0022-3077(200005)83:5<2519:AOPGIM>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
TEMPORAL-LOBE EPILEPSY; AMINO-ACID RECEPTORS; IN-VITRO; SYNAPTIC TRANSMISSION; HIPPOCAMPUS; INVITRO; LOCALIZATION; SUBTYPES; NEURONS; L-AP4;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
41
Recensione:
Indirizzi per estratti:
Indirizzo: Woodhall, G Univ Bristol, Sch Med Sci, Dept Physiol, Bristol BS8 1TD, Avon, England Univ Bristol Bristol Avon England BS8 1TD 1TD, Avon, England
Citazione:
D.I. Evans et al., "Activation of presynaptic group III metabotropic receptors enhances glutamate release in rat entorhinal cortex", J NEUROPHYS, 83(5), 2000, pp. 2519-2525

Abstract

The role of group III metabotropic glutamate receptors (mGluRs) in modulating excitatory synaptic transmission was investigated in the rat entorhinalcortex (EC) in vitro. AMPA receptor-mediated excitatory postsynaptic currents (EPSCs) were recorded in the whole cell configuration of the patch-clamp technique from visually identified neurons in layers V and II. In layer V, bath application of the specific group III mGluR agonist L(+)-2-amino-4-phosphonobutyric acid (L-AP4, 500 mu M) resulted in a marked facilitation ofboth spontaneous and activity-independent "miniature" (s/ mEPSC) event frequency. Thr facilitatory effect of L-AP4 (100 mu M) on sEPSC frequency prevailed in the presence of DL-2-amino-5-phosphonopentanoic acid (100 mu M) but was abolished by the group III antagonist (RS)-cyclopropyl-4-phosphonophenylglycine (20 mu M). These data confirmed that group III mGluRs, and not N-methyl-D-aspartate (NMDA) receptors were involved in the response to L-AP4. Bath application of the specific mGluR4a agonist (1S,3R,4S)-1-aminocyclopentane-1,2, 4-tricarboxylic acid (20 mu M) also had a facilitatory effect on sEPSC frequency, suggesting involvement of mGluR4a. In layer II neurons, L-AP4 caused a reduction in sEPSC frequency but did not affect mEPSCs recorded in the presence of tetrodotoxin. These findings suggest that a group III mGluR with mGluR4a-like pharmacology is involved in modulating synaptic transmission in layer V cells of the EC. The effect on mEPSCs suggests that this receptor is located presynaptically and that its activation results ina direct facilitation of glutamate release. This novel facilitatory effectis specific to layer V and, to our knowledge, is the first report of a direct facilitatory action of group III mGluRs on synaptic transmission. In layer II, L-AP4 had an inhibitory effect on glutamate release similar to thatreported in other brain regions.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 12/07/20 alle ore 11:24:54