title: Hippocampal place cell responses to distal and proximal cue manipulations in dopamine D2 receptor-knockout mice.
abstract: The human hippocampus is critical for learning and memory. In rodents, hippocampal pyramidal neurons fire in a location-specific manner and form relational representations of environmental cues. The important roles of dopaminergic D1 receptors in learning and in hippocampal neural synaptic plasticity in novel environments have been previously shown. However, the roles of D2 receptors in hippocampal neural plasticity in response to novel and familiar spatial stimuli remain unclear. In order to clarify this issue, we recorded from hippocampal neurons in dopamine D2 receptor-knockout (D2R-KO) mice and their wild-type (WT) littermates during manipulations of distinct spatial cues in familiar and novel environments. Here, we report that D2R-KO mice showed substantial deficits in place-cell properties (number of place cells, intra-field firing rates, spatial tuning, and spatial coherence). Furthermore, although place cells in D2R-KO mice responded to manipulations of distal and proximal cues in both familiar and novel environments in a manner that was similar to place cells in WT mice, place fields were less stable in the D . The axes represent the differences between the peak and the valley of each waveform of EL2 and EL3.2R-KO mice in the familiar environment, but not in the novel environment. The present results suggested that D2 receptors in the hippocampus are important for place response stability. The place-cell properties of D2R-KO mice were similar to aged animals, suggesting that the alterations of place-cell properties in aged animals might be ascribed partly to alterations in the D2R in the HF of aged animals.
authors.affiliation: System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan.
authors.forename: Chien Le
authors.initials: CL
authors.lastname: Nguyen
authors.affiliation: System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan.
authors.forename: Anh Hai
authors.initials: AH
authors.lastname: Tran
authors.affiliation: System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan.
authors.forename: Jumpei
authors.initials: J
authors.lastname: Matsumoto
authors.affiliation: System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan.
authors.forename: Etsuro
authors.initials: E
authors.lastname: Hori
authors.affiliation: Integrative Neuroscience, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan.
authors.forename: Teruko
authors.initials: T
authors.lastname: Uwano
authors.affiliation: Integrative Neuroscience, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan.
authors.forename: Taketoshi
authors.initials: T
authors.lastname: Ono
authors.affiliation: System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan. Electronic address: nishijo@med.u-toyama.ac.jp.
authors.forename: Hisao
authors.initials: H
authors.lastname: Nishijo
mesh_terms: D000200:Action Potentials; D000818:Animals; D056547:CA1 Region, Hippocampal / Q000502:physiology*; D002452:Cell Count; D003463:Cues; D004567:Electrodes, Implanted; D004777:Environment; D008297:Male; D018345:Mice, Knockout; D009043:Motor Activity / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D009483:Neuropsychological Tests; D011601:Psychophysics; D017448:Receptors, Dopamine D2 / Q000235:genetics / Q000378:metabolism*; D021641:Recognition, Psychology / Q000502:physiology; D013028:Space Perception / Q000502:physiology*
chemical_list: D017448:Receptors, Dopamine D2
keywords: D2 Receptor-knockout; Dopamine; Environmental manipulation; Hippocampus; Mice; Place-cell