title: Characterization of glutamate receptors induced in Xenopus oocytes after injection of rat brain mRNA.
abstract: Xenopus oocytes in which poly(A)+ mRNA isolated from rat brains were previously injected, exhibited at least 3 categories of current responses to excitatory amino acids. They were oscillatory responses to glutamate (Glu) or quisqualate (QA), smooth large responses to kainate (KA), and smooth small responses to Glu and QA. Oscillatory responses were mediated by a metabotropic type of Glu receptor which is coupled to a G-protein but not directly to an ionic channel. Amplitudes of smooth Glu responses and smooth QA responses were similar in size, and were not additive to each other, suggesting a common receptor mediating both responses. L-Glutamylglycine inhibited KA responses in a competitive manner without affecting smooth Glu/QA responses, indicating that KA and smooth Glu/QA responses were mediated by separate receptors. From these results, it was concluded that the injection of rat brain mRNA induced at least 3 different glutamatergic receptors: receptors mediating (a) KA responses and (b) smooth Glu/QA responses, and (c) the metabotropic Glu receptor. The former two may most likely correspond to Glu receptor subtypes preferring KA and QA, respectively, as seen in the brain.
authors.affiliation: Department of Cellular Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Hirono
authors.forename: I
authors.initials: I
authors.lastname: Ito
authors.forename: S
authors.initials: S
authors.lastname: Yamagishi
authors.forename: H
authors.initials: H
authors.lastname: Sugiyama
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D007608:Kainic Acid / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D010069:Oxadiazoles / Q000494:pharmacology; D016318:Quisqualic Acid; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D014982:Xenopus laevis
chemical_list: D005971:Glutamates; D010069:Oxadiazoles; D012333:RNA, Messenger; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter; D018698:Glutamic Acid; D016318:Quisqualic Acid; D007608:Kainic Acid