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Titolo:
Modulation of the intracellular calcium concentration in photoreceptor terminals by a presynaptic metabotropic glutamate receptor
Autore:
Koulen, P; Kuhn, R; Wassle, H; Brandstatter, JH;
Indirizzi:
Max Planck Inst Hirnforsch, Abt Neuroanat, D-60528 Frankfurt, Germany Max Planck Inst Hirnforsch Frankfurt Germany D-60528 Frankfurt, Germany Novartis, CNS Res, CH-4002 Basel, Switzerland Novartis Basel SwitzerlandCH-4002 , CNS Res, CH-4002 Basel, Switzerland
Titolo Testata:
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
fascicolo: 17, volume: 96, anno: 1999,
pagine: 9909 - 9914
SICI:
0027-8424(19990817)96:17<9909:MOTICC>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
ROD BIPOLAR CELLS; RAT RETINA; MAMMALIAN RETINA; G-PROTEIN; 2-AMINO-4-PHOSPHONOBUTYRIC ACID; DEVELOPMENTAL EXPRESSION; SYNAPTIC TRANSMISSION; CONE PHOTORECEPTORS; LOCALIZATION; RELEASE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Brandstatter, JH Max Planck Inst Hirnforsch, Abt Neuroanat, Deutschordenstr 46, D-60528 Frankfurt, Germany Max Planck Inst Hirnforsch Deutschordenstr46 Frankfurt Germany D-60528
Citazione:
P. Koulen et al., "Modulation of the intracellular calcium concentration in photoreceptor terminals by a presynaptic metabotropic glutamate receptor", P NAS US, 96(17), 1999, pp. 9909-9914

Abstract

Fast excitatory neurotransmission in the central nervous system is mediated through glutamate acting on ionotropic glutamate receptors, However, glutamate acting on metabotropic glutamate receptors (mGluRs) can also exert aninhibitory action. Here, we report by immunocytochemistry and physiology, to our knowledge, the first glutamate receptor to be found in terminals of photoreceptors in the mammalian retina-the group III metabotropic glutamatereceptor mGluR8, Glutamate is the transmitter of photoreceptors, and thus mGluR8 functions as an autoreceptor. Activation of mGluR8 by the group III mGluR agonists L-2-amino-4-phosphonobutyrate and L-serine-O-phosphate, or by glutamate itself, evokes a decrease in the intracellular calcium ion concentration ([Ca2+](i)) in isolated photoreceptors. This effect is blocked bythe group III mGluR antagonists (RS)-alpha-methyl-4-phosphonophenylglycineand (RS)-alpha-methylserine-O-phosphate. Agonists for other classes of glutamate receptors-N-methyl-D-aspartic acid, quisqualic acid, kainic acid, or(RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-have no effect on the [Ca2+](i) in isolated photoreceptors. The down-regulation of the [Ca2+](i) in photoreceptors by mGluR8 provides evidence for an inhibitory feedback loop at the photoreceptor synapse in the mammalian retina. This negative feedback may be a mechanism for the fine adjustment of the light-regulated release of glutamate from photoreceptors and may serve as a safety device against excitotoxic levels of release at this tonic synapse. Such a mechanism may provide a model for feedback inhibition in other parts of the central nervous system.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/07/20 alle ore 21:05:18