title: Severely impaired learning and altered neuronal morphology in mice lacking NMDA receptors in medium spiny neurons.
abstract: The striatum is composed predominantly of medium spiny neurons (MSNs) that integrate excitatory, glutamatergic inputs from the cortex and thalamus, and modulatory dopaminergic inputs from the ventral midbrain to influence behavior. Glutamatergic activation of AMPA, NMDA, and metabotropic receptors on MSNs is important for striatal development and function, but the roles of each of these receptor classes remain incompletely understood. Signaling through NMDA-type glutamate receptors (NMDARs) in the striatum has been implicated in various motor and appetitive learning paradigms. In addition, signaling through NMDARs influences neuronal morphology, which could underlie their role in mediating learned behaviors. To study the role of NMDARs on MSNs in learning and in morphological development, we generated mice lacking the essential NR1 subunit, encoded by the Grin1 gene, selectively in MSNs. Although these knockout mice appear normal and display normal 24-hour locomotion, they have severe deficits in motor learning, operant conditioning and active avoidance. In addition, the MSNs from these knockout mice have smaller cell bodies and decreased dendritic length compared to littermate controls. We conclude that NMDAR signaling in MSNs is critical for normal MSN morphology and many forms of learning.
authors: Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America.
authors: Lisa R
authors: LR
authors: Beutler
authors: Kiara C
authors: KC
authors: Eldred
authors: Albert
authors: A
authors: Quintana
authors: C Dirk
authors: CD
authors: Keene
authors: Shannon E
authors: SE
authors: Rose
authors: Nadia
authors: N
authors: Postupna
authors: Thomas J
authors: TJ
authors: Montine
authors: Richard D
authors: RD
authors: Palmiter
mesh_terms: D000818:Animals; D001362:Avoidance Learning; D049628:Body Size; D003216:Conditioning, Operant; D005239:Fear; D007858:Learning; D008124:Locomotion; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009043:Motor Activity; D009474:Neurons / Q000473:pathology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000172:deficiency* / Q000378:metabolism; D013647:Task Performance and Analysis
chemical_list: C409466:NR1 NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate