title: A novel metabotropic glutamate receptor expressed in the retina and olfactory bulb.
abstract: A novel metabotropic glutamate receptor, mGluR8, was identified by screening a mouse retina cDNA library. This receptor is most related to mGluR4, mGluR7, and mGluR6 (74%, 74%, and 70% identical amino acid residues, respectively). Similar to these receptors, stimulation by L-glutamate or L-2-amino-4-phosphonobutyrate (L-APB) of Chinese hamster ovary (CHO) cells stably transfected with mGluR8 result in the inhibition of forskolin-stimulated adenylyl cyclase. In situ hybridization studies revealed a strong expression of the mGluR8 gene in the olfactory bulb, accessory olfactory bulb, and mammillary body. A weaker expression was found in the retina, and in scattered cells in the cortex and hindbrain. During development, the distribution of mGluR8 expression was more widespread. These results extend the diversity of metabotropic glutamate receptors in the CNS. Because at least two APB receptors are expressed in the retina, the use of this drug to block selectively the ON pathway needs to be reconsidered. The pharmacology and expression of mGluR8 in mitral/tufted cells suggest it could be a presynaptic receptor modulating glutamate release by these cells at their axon terminals in the entorhinal cortex.
authors.affiliation: Margaret M. Dyson Vision Research Institute, Department of Ophthalmology, Cornell University Medical College, New York, New York 10021, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Duvoisin
authors.forename: C
authors.initials: C
authors.lastname: Zhang
authors.forename: K
authors.initials: K
authors.lastname: Ramonell
mesh_terms: D000595:Amino Acid Sequence; D000613:Aminobutyrates / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D003001:Cloning, Molecular; D005576:Colforsin / Q000494:pharmacology; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism; D017931:DNA Primers; D018076:DNA, Complementary; D015870:Gene Expression; D015723:Gene Library; D018698:Glutamic Acid / Q000494:pharmacology*; D017403:In Situ Hybridization; D051379:Mice; D008969:Molecular Sequence Data; D005810:Multigene Family; D009830:Olfactory Bulb / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D018094:Receptors, Metabotropic Glutamate / Q000096:biosynthesis*; D011994:Recombinant Proteins / Q000096:biosynthesis; D012160:Retina / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014162:Transfection
chemical_list: D000613:Aminobutyrates; D017931:DNA Primers; D018076:DNA, Complementary; D012333:RNA, Messenger; D018094:Receptors, Metabotropic Glutamate; D011994:Recombinant Proteins; D005576:Colforsin; D018698:Glutamic Acid; D000242:Cyclic AMP; C012729:2-amino-4-phosphonobutyric acid