Linked Life Data

9651535

Source:http://linkedlifedata.com/resource/pubmed/id/9651535

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2-3
pubmed:dateCreated
1998-8-28
pubmed:abstractText
Glutamate receptors are important in neural plasticity, neural development and neurodegeneration. N-methyl-d-aspartate (NMDA) receptors and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)/kainate receptors act as glutamate-gated cation channels, whereas metabotropic receptors (mGluRs) modulate the production of second messengers via G proteins. Molecular studies from our and other laboratories indicated that NMDA receptors and mGluRs exist as multiple subunits (NMDAR1 and NMDAR2A-2D) and multiple subtypes (mGluR1-mGluR8). In light of the molecular diversity of glutamate receptors, we explored the function and intracellular signaling mechanisms of different members of glutamate receptors. In the visual system, retinal bipolar cells receive glutamate transmission from photoreceptors and contribute to segregating visual signals into ON and OFF pathways. The molecularly cloned mGluR6 is restrictedly expressed at the postsynaptic site of ON-bipolar cells in both rod and cone systems. Gene targeting of mGluR6 results in a loss of ON responses without changing OFF responses and severely impairs detecting visual contrasts. Since AMPA receptors mediate OFF responses in OFF-bipolar cells, two distinct types of glutamate receptors effectively operate for ON and OFF responses. mGluR1 and mGluR5 are both coupled to inositol triphosphate (IP3)/calcium signal transduction with an identical agonist selectivity. Single-cell intracellular calcium ([Ca2+]i) recordings indicated that glutamate evokes a non-oscillatory and oscillatory [Ca2+]i response in mGluR1-expressing and mGluR5-expressing cells, respectively. This difference results from a single amino acid substitution, aspartate of mGluR1 or threonine of mGluR5, at the G protein-interacting carboxy-terminal domains. Protein kinase C phosphorylation of the threonine of mGluR5 is responsible for inducing [Ca2+]i oscillations in mGluR5-expressing cells and cultured glial cells. Thus, the two closely related mGluR subtypes mediate diverging intracellular signaling in glutamate transmission.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:author
pubmed:copyrightInfo
Copyright 1998 Elsevier Science B.V. All rights reserved.
pubmed:volume
26
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
230-5
pubmed:dateRevised
2007-2-26
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Glutamate receptors: brain function and signal transduction.
pubmed:affiliation
Department of Biological Sciences, Kyoto University Faculty of Medicine, Yoshida, Sakyo-ku, Kyoto 606, Japan. snakanis@phy.med.kyoto-u.ac.jp
pubmed:publicationType
Journal Article, Review, Research Support, Non-U.S. Gov't