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Titolo:
POSTSYNAPTIC RESPONSES OF HORIZONTAL CELLS IN THE TIGER SALAMANDER RETINA ARE MEDIATED BY AMPA-PREFERRING RECEPTORS
Autore:
YANG JH; MAPLE B; GAO F; MAGUIRE G; WU SM;
Indirizzi:
BAYLOR COLL MED,CULLEN EYE INST,1 BAYLOR PLAZA HOUSTON TX 77030 BAYLOR COLL MED,CULLEN EYE INST HOUSTON TX 77030
Titolo Testata:
Brain research
fascicolo: 1, volume: 797, anno: 1998,
pagine: 125 - 134
SICI:
0006-8993(1998)797:1<125:PROHCI>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
GLUTAMATE-RECEPTOR; BIPOLAR CELLS; SYNAPTIC TRANSMISSION; KAINATE RECEPTORS; ACID; CYCLOTHIAZIDE; NEURONS; DESENSITIZATION; CURRENTS; GLYCINE;
Keywords:
GLUTAMATE; CYCLOTHIAZIDE; GYKI52466; CONCANAVALIN A; RECEPTOR DESENSITIZATION; LIGHT RESPONSE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
47
Recensione:
Indirizzi per estratti:
Citazione:
J.H. Yang et al., "POSTSYNAPTIC RESPONSES OF HORIZONTAL CELLS IN THE TIGER SALAMANDER RETINA ARE MEDIATED BY AMPA-PREFERRING RECEPTORS", Brain research, 797(1), 1998, pp. 125-134

Abstract

The postsynaptic responses of sign-preserving second-order retinal neurons (horizontal cells (HCs) and off-bipolar cells) are mediated by CNQX-sensitive AMPA/KA glutamate receptors. In this study we used receptor-specific allosteric regulators of desensitization and selected antagonists to determine the glutamate receptor subtypes in tiger salamander horizontal cells. Two approaches were employed in this study. The first was to measure postsynaptic currents induced by exogenously applied glutamate under voltage clamp conditions in living retinal slices;and the second was to record voltage responses controlled by endogenous glutamate released from photoreceptors in whole retinas. Application of 100 mu M cyclothiazide (a specific AMPA receptor desensitization blocker) enhanced the glutamate-induced current by about 5 fold. In contrast, 300 mu gml(-1) ConA (a specific kainate receptor desensitization blocker), had no effect. GYKI 52466 (a specific AMPA receptor antagonist) at 30 mu M almost completely suppressed the glutamate-induced inward current in HCs. Cyclothiazide at 100 mu M depolarized the HC dark membrane potential by about 5 mV and reduced the amplitudes of the voltage responses to dim Lights, but enhanced the voltage responses to bright lights. Cyclothiazide had no effect on either the dark potential or the light responses of rods and cones. Con A at 300 mu gml(-1) had no effect on either the dark potential or the light responses of theHC. GYKI 52466 (30 mu M) hyperpolarized the HC dark membrane potential by about 55 mV and almost completely suppressed the light responses. We conclude from these results that the postsynaptic glutamate- and Light-induced responses in the tiger salamander retinal horizontal cells are mediated by AMPA-preferring, and not kainate-preferring glutamate receptors. The functional roles of AMPA receptors and their desensitization kinetics in visual information processing are discussed. (C) 1998 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 15/07/20 alle ore 15:02:42