title: Ketogenic diet does not impair spatial ability controlled by the hippocampus in male rats.
abstract: A ketogenic diet was recently shown to reduce glutamate accumulation in synaptic vesicles, decreasing glutamate transmission. We questioned whether a ketogenic diet affects hippocampal function, as glutamate transmission is critically involved in visuospatial ability. In the present study, male Wistar rats were maintained on a ketogenic diet containing 10% protein and 90% fat with complements for 3 weeks to change their energy expenditure from glucose-dependent to fat-dependent. Control rats were fed a diet containing 10% protein, 10% fat, and 80% carbohydrates. The fat-dependent energy expenditure induced by the ketogenic diet led to decreased body weight and increased blood ketone production, though the rats in the two groups consumed the same number of calories. The ketogenic diet did not alter food preferences for the control or high-fat diet containing 10% protein, 45% fat, and 45% carbohydrates. Anxiety in the open field was not altered by ingestion the ketogenic diet. However, rats fed the ketogenic diet performed better in the Y-maze test than rats fed the control diet. No difference was observed between the two groups in the Morris water maze test. Finally, Western blot revealed that the hippocampal expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptor subunit 1 (GluR1) was significantly increased in mice fed a ketogenic diet. These results suggest that hippocampal function is not impaired by a ketogenic diet and we speculate that the fat-dependent energy expenditure does not impair visuospatial ability.
authors.affiliation: Department of Physiology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki 216-8511, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Fukushima
authors.affiliation: Department of Physiology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki 216-8511, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ogura
authors.affiliation: Department of Physiology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki 216-8511, Japan.
authors.forename: Miyako
authors.initials: M
authors.lastname: Furuta
authors.affiliation: Department of Physiology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki 216-8511, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Kakehashi
authors.affiliation: Department of Physiology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki 216-8511, Japan. Electronic address: toshiya@marianna-u.ac.jp.
authors.forename: Toshiya
authors.initials: T
authors.lastname: Funabashi
authors.affiliation: Department of Physiology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki 216-8511, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Akema
mesh_terms: D000821:Animal Feed; D000818:Animals; D001007:Anxiety / Q000503:physiopathology; D001786:Blood Glucose / Q000502:physiology; D015153:Blotting, Western; D001835:Body Weight / Q000502:physiology; D020148:Butyric Acid / Q000097:blood; D002755:Choice Behavior / Q000502:physiology; D055423:Diet, Ketogenic; D005247:Feeding Behavior / Q000502:physiology; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000378:metabolism; D065854:Spatial Navigation / Q000502:physiology*; D055697:Taste Perception
chemical_list: D001786:Blood Glucose; D020148:Butyric Acid; D018091:Receptors, AMPA
keywords: AMPA receptors; Hippocampus; Ketogenic diet; Ketone; Y-maze