Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
PRESYNAPTIC DEPRESSION AT A CALYX SYNAPSE - THE SMALL CONTRIBUTION OFMETABOTROPIC GLUTAMATE RECEPTORS
Autore:
VONGERSDORFF H; SCHNEGGENBURGER R; WEIS S; NEHER E;
Indirizzi:
MAX PLANCK INST BIOPHYS CHEM,ABT MEMBRANBIOPHYS,FASSBERG D-37077 GOTTINGEN GERMANY
Titolo Testata:
The Journal of neuroscience
fascicolo: 21, volume: 17, anno: 1997,
pagine: 8137 - 8146
SICI:
0270-6474(1997)17:21<8137:PDAACS>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
CULTURED HIPPOCAMPAL-NEURONS; EXCITATORY POSTSYNAPTIC CURRENTS; FREQUENCY-DEPENDENT DEPRESSION; LONG-TERM DEPRESSION; AUDITORY BRAIN-STEM; SQUID GIANT SYNAPSE; TRANSMITTER RELEASE; RAT HIPPOCAMPUS; MEDIAL NUCLEUS; TRAPEZOID BODY;
Keywords:
EPSCS; NMDA; AMPA; COMPETITIVE ANTAGONIST; SYNAPTIC TRANSMISSION; AUDITORY BRAIN-STEM SLICES; SECRETION; SHORT-TERM PLASTICITY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
75
Recensione:
Indirizzi per estratti:
Citazione:
H. Vongersdorff et al., "PRESYNAPTIC DEPRESSION AT A CALYX SYNAPSE - THE SMALL CONTRIBUTION OFMETABOTROPIC GLUTAMATE RECEPTORS", The Journal of neuroscience, 17(21), 1997, pp. 8137-8146

Abstract

Synaptic depression of evoked EPSCs was quantified with stimulation frequencies ranging from 0.2 to 100 Hz at the single CNS synapse formedby the calyx of Held in the rat brainstem. Half-maximal depression occurred at approximate to 1 Hz, with 10 and 100 Hz stimulation frequencies reducing EPSC amplitudes to approximate to 30% and approximate to 10% of their initial magnitude, respectively. The time constant of recovery from depression elicited by 10 Hz afferent fiber stimulation was4.2 sec. AMPA and NMDA receptor-mediated EPSCs depressed in parallel at 1-5 Hz stimulation frequencies, suggesting that depression was induced by presynaptic mechanism(s) that reduced glutamate release. To determine the contribution of autoreceptors to depression, we studied theinhibitory effects of the metabotropic glutamate receptor (mGluR) agonists (1S, 3S)-ACPD and L-AP4 and found them to be reversed in a dose-dependent manner by (RS)-alpha-cyclopropyl-4-phosphonophenylglycine (CPPG), a novel and potent competitive antagonist of mGluRs. At 300 mu M, CPPG completely reversed the effects of L-AP4 and (1S, 3S)-ACPD, butreduced 5-10 Hz elicited depression by only approximate to 6%. CPPG-sensitive mGluRs, presumably activated by glutamate spillover during physiological synaptic transmission, thus contribute on the order of only 10% to short-term synaptic depression. We therefore suggest that themain mechanism contributing to the robust depression elicited by 5-10Hz afferent fiber stimulation of the calyx of Held synapse is synaptic vesicle pool depletion.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 15/07/20 alle ore 08:18:12