title: Dopamine D1 receptors regulate protein synthesis-dependent long-term recognition memory via extracellular signal-regulated kinase 1/2 in the prefrontal cortex.
abstract: Several lines of evidence suggest that extracellular signal-regulated kinase1/2 (ERK1/2) and dopaminergic system is involved in learning and memory. However, it remains to be determined if the dopaminergic system and ERK1/2 pathway contribute to cognitive function in the prefrontal cortex (PFC). The amount of phosphorylated ERK1/2 was increased in the PFC immediately after exposure to novel objects in the training session of the novel object recognition test. An inhibitor of ERK kinase impaired long-term recognition memory 24 h after the training although short-term memory tested 1 h after the training was not affected by the treatment. The dopamine D1 receptor agonist increased ERK1/2 phosphorylation in the PFC in vivo as well as in cortical neurons in vitro. Microinjection of the dopamine D1 receptor antagonist into the PFC impaired long-term recognition memory whereas the D2 receptor antagonist had no effect. Immunohistochemistry revealed that exposure to novel objects resulted in an increase in c-Fos expression in the PFC. Microinjection of the protein synthesis inhibitor anisomycin into the PFC impaired the long-term recognition memory. These results suggest that the activation of ERK1/2 following the stimulation of dopamine D1 receptors is necessary for the protein synthesis-dependent long-term retention of recognition memory in the PFC.
authors.affiliation: Laboratory of Neuropsychopharmacology, Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Nagai
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Takuma
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kamei
authors.forename: Yukio
authors.initials: Y
authors.lastname: Ito
authors.forename: Noritaka
authors.initials: N
authors.lastname: Nakamichi
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ibi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Nakanishi
authors.forename: Masaaki
authors.initials: M
authors.lastname: Murai
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mizoguchi
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Nabeshima
authors.forename: Kiyofumi
authors.initials: K
authors.lastname: Yamada
mesh_terms: D000818:Animals; D004789:Enzyme Activation / Q000502:physiology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D010766:Phosphorylation; D017397:Prefrontal Cortex / Q000201:enzymology* / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D017447:Receptors, Dopamine D1 / Q000502:physiology*; D021641:Recognition, Psychology / Q000502:physiology*; D013997:Time Factors
chemical_list: D009419:Nerve Tissue Proteins; D016760:Proto-Oncogene Proteins c-fos; D017447:Receptors, Dopamine D1; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3