title: Degeneration of the amygdala/piriform cortex and enhanced fear/anxiety behaviors in sodium pump alpha2 subunit (Atp1a2)-deficient mice.
abstract: The sodium pump is the enzyme responsible for the maintenance of Na+ and K+ gradients across the cell membrane. Four isoforms of the catalytic alpha subunit have been identified, but their individual roles remain essentially unknown. To investigate the necessary functions of the alpha2 subunit in vivo, we generated and analyzed mice defective in the alpha2 subunit gene. Mice homozygous for the alpha2 mutation died just after birth and displayed selective neuronal apoptosis in the amygdala and piriform cortex. In these regions, high expression of c-Fos before apoptosis indicated neural hyperactivity, and re-uptake of glutamic acid and GABA into P2 fraction containing crude synaptosome was impaired. These results indicate that the alpha2 subunit plays a critical role regulating neural activity in the developing amygdala and piriform cortex. Further supporting a role of the alpha2 subunit in the function of the amygdala, heterozygous adult mice showed augmented fear/anxiety behaviors and enhanced neuronal activity in the amygdala and piriform cortex after conditioned fear stimuli.
authors.affiliation: Department of Biology Jichi Medical School, Kawachi, Tochigi 329-0498, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Ikeda
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Onaka
authors.forename: Makoto
authors.initials: M
authors.lastname: Yamakado
authors.forename: Junichi
authors.initials: J
authors.lastname: Nakai
authors.forename: Tomo-o
authors.initials: TO
authors.lastname: Ishikawa
authors.forename: Makoto M
authors.initials: MM
authors.lastname: Taketo
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Kawakami
mesh_terms: D000679:Amygdala / Q000473:pathology*; D000818:Animals; D001007:Anxiety / Q000235:genetics; D017209:Apoptosis; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism; D001522:Behavior, Animal / Q000502:physiology; D001923:Brain Chemistry; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000473:pathology*; D003214:Conditioning, Classical; D005239:Fear / Q000502:physiology; D005804:Genes, Lethal; D018698:Glutamic Acid / Q000378:metabolism / Q000493:pharmacokinetics; D006579:Heterozygote; D006720:Homozygote; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D009154:Mutation; D019636:Neurodegenerative Diseases / Q000473:pathology / Q000503:physiopathology; D009833:Olfactory Pathways / Q000473:pathology*; D021122:Protein Subunits / Q000172:deficiency / Q000235:genetics; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000172:deficiency* / Q000235:genetics; D013574:Synaptosomes / Q000737:chemistry / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism / Q000493:pharmacokinetics
chemical_list: D021122:Protein Subunits; D016760:Proto-Oncogene Proteins c-fos; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; C401838:Atp1a2 protein, mouse; D000254:Sodium-Potassium-Exchanging ATPase