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Titolo:
The role of NMDA channels in rabbit retinal directional selectivity
Autore:
Tjepkes, DS; Amthor, FR;
Indirizzi:
Univ Alabama, Dept Psychol, Birmingham, AL 35294 USA Univ Alabama Birmingham AL USA 35294 pt Psychol, Birmingham, AL 35294 USA Univ Alabama, Dept Neurobiol, Birmingham, AL 35294 USA Univ Alabama Birmingham AL USA 35294 Neurobiol, Birmingham, AL 35294 USA
Titolo Testata:
VISUAL NEUROSCIENCE
fascicolo: 2, volume: 17, anno: 2000,
pagine: 291 - 302
SICI:
0952-5238(200003/04)17:2<291:TRONCI>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
COMPLEX RECEPTIVE-FIELDS; STARBURST AMACRINE CELLS; MOUSE CENTRAL NEURONS; GANGLION-CELLS; ACETYLCHOLINE-RELEASE; DENDRITIC MORPHOLOGY; CHOLINERGIC NEURONS; ACTIVATED CHANNELS; INHIBITION; MOTION;
Keywords:
NMDA; directional selectivity; retinal ganglion cells;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
47
Recensione:
Indirizzi per estratti:
Indirizzo: Amthor, FR Univ Alabama, Dept Psychol, Birmingham, AL 35294 USA Univ Alabama Birmingham AL USA 35294 Birmingham, AL 35294 USA
Citazione:
D.S. Tjepkes e F.R. Amthor, "The role of NMDA channels in rabbit retinal directional selectivity", VIS NEUROSC, 17(2), 2000, pp. 291-302

Abstract

It has been previously demonstrated that the majority of the glutamatergicinput to directionally selective (DS) ganglion cells in the rabbit retina is mediated by NMDA receptors. To examine whether NMDA channels have any role in directional selectivity, we eliminated magnesium from the superfusionmedium to prevent the magnesium block of the channels at hyperpolarized membrane potentials. During superfusion in magnesium-free media, the responseto null-direction motion increased to the level of the response to preferred-direction motion. This effect was specifically mediated by NMDA channelsbecause subsequent blocking of the NMDA channels with AP7 restored directional selectivity. We also tested whether the increase in the null-directionresponse in magnesium-free medium was due to an increased release of acetylcholine from the cholinergic;amacrine cells, rather than an effect on the DS ganglion cells themselves, by blocking acetylcholine transmission with d-tubocurarine during superfusion with the magnesium-free medium. During zero-magnesium superfusion, d-tubocurarine reduced both the preferred-and null-direction responses of DS ganglion cells but did not restore directional selectivity. These findings suggest that null-direction motion normally causes portions of the dendritic membrane of the directionally selective ganglion cell to be maintained at a sufficiently negative potential that the NMDAchannels are blocked by magnesium ions. This result is discussed in terms of several models for the mechanisms of directional selectivity.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 11/07/20 alle ore 07:54:00