title: Memory in Caenorhabditis elegans is mediated by NMDA-type ionotropic glutamate receptors.
abstract: Learning and memory are essential processes of both vertebrate and invertebrate nervous systems that allow animals to survive and reproduce. The neurotransmitter glutamate signals via ionotropic glutamate receptors (iGluRs) that have been linked to learning and memory formation; however, the signaling pathways that contribute to these behaviors are still not well understood. We therefore undertook a genetic and electrophysiological analysis of learning and memory in the nematode Caenorhabditis elegans. Here, we show that two genes, nmr-1 and nmr-2, are predicted to encode the subunits of an NMDA-type (NMDAR) iGluR that is necessary for memory retention in C. elegans. We cloned nmr-2, generated a deletion mutation in the gene, and showed that like nmr-1, nmr-2 is required for in vivo NMDA-gated currents. Using an associative-learning paradigm that pairs starvation with the attractant NaCl, we also showed that the memory of a learned avoidance response is dependent on NMR-1 and NMR-2 and that expression of NMDARs in a single pair of interneurons is sufficient for normal memory. Our results provide new insights into the molecular and cellular mechanisms underlying the memory of a learned event.
authors.affiliation: Department of Physical Information, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kano
authors.forename: Penelope J
authors.initials: PJ
authors.lastname: Brockie
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Sassa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fujimoto
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawahara
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Iino
authors.forename: Jerry E
authors.initials: JE
authors.lastname: Mellem
authors.forename: David M
authors.initials: DM
authors.lastname: Madsen
authors.forename: Ryuji
authors.initials: R
authors.lastname: Hosono
authors.forename: Andres V
authors.initials: AV
authors.lastname: Maricq
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001070:Appetitive Behavior / Q000187:drug effects; D001245:Association Learning; D001362:Avoidance Learning; D017173:Caenorhabditis elegans / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D002633:Chemotaxis; D005502:Food; D007395:Interneurons / Q000378:metabolism; D008568:Memory; D008969:Molecular Sequence Data; D009154:Mutation; D016202:N-Methylaspartate / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000494:pharmacology; D013217:Starvation
chemical_list: D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; C436186:NMR-1 protein, C elegans; C531979:NMR-2 protein, C elegans; D016194:Receptors, N-Methyl-D-Aspartate; C437625:unc-10 protein, C elegans; D012965:Sodium Chloride; D016202:N-Methylaspartate