title: Regional vulnerability of the hippocampus to repeated motor activity deprivation.
abstract: Spontaneous vertical and horizontal exploratory movements are integral components of rodent behavior. Little is known, however, about the structural and functional consequences of restricted spontaneous exploration. Here, we report two experiments to probe whether restriction in vertical activity (rearing) in rats could induce neuro-hormonal and behavioral disturbances. Rearing movements in rats were deprived for 3h/day for 30 consecutive days by placing the animal into a circular tunnel task. Rats temporarily deprived of rearing behavior showed elevated plasma corticosterone levels but no detectable psychological distress and/or anxiety-related behavior within an elevated plus maze. However, rats emitted a greater number of 22-kHz ultrasonic vocalizations and spent significantly more time vocalizing than controls when deprived of their rearing behavior. Despite intact spatial performance within wet- and dry-land spatial tasks, rearing-deprived rats also exhibited a significant alteration in search strategies within both spatial tasks along with reduced volume and neuron number in the hippocampal subregion CA2. These data suggest a new approach to test the importance of free exploratory behavior in endocrine and structural manifestations. The results support a central role of the CA2 in spontaneous exploratory behavior and vulnerability to psychological stress.
authors.affiliation: Golestan University of Medical Sciences, Faculty of Nursing & Midwifery, Gorgan, Islamic Republic of Iran; Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB T1K 3M4 Canada. Electronic address: jamshid.faraji@uleth.ca.
authors.forename: Jamshid
authors.initials: J
authors.lastname: Faraji
authors.affiliation: Babol University of Medical Sciences, Department of Anatomy, Biology and Molecular Research Center, Babol, Islamic Republic of Iran.
authors.forename: Nabiollah
authors.initials: N
authors.lastname: Soltanpour
authors.affiliation: Avicenna Institute of Neuroscience, Department of Behavioural Studies, Yazd, Islamic Republic of Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Moeeini
authors.affiliation: Golestan University of Medical Sciences, Faculty of Nursing & Midwifery, Gorgan, Islamic Republic of Iran.
authors.forename: Seyed Abedin
authors.initials: SA
authors.lastname: Hosseini
authors.affiliation: Avicenna Institute of Neuroscience, Department of Behavioural Studies, Yazd, Islamic Republic of Iran.
authors.forename: Shiva
authors.initials: S
authors.lastname: Pakdel
authors.affiliation: Golestan University of Medical Sciences, Department of Anatomy, Gorgan, Islamic Republic of Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Moharrerie
authors.affiliation: Avicenna Institute of Neuroscience, Department of Behavioural Studies, Yazd, Islamic Republic of Iran.
authors.forename: Kaveh
authors.initials: K
authors.lastname: Arjang
authors.affiliation: Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB T1K 3M4 Canada.
authors.forename: Nasrin
authors.initials: N
authors.lastname: Soltanpour
authors.affiliation: Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB T1K 3M4 Canada.
authors.forename: Gerlinde A S
authors.initials: GA
authors.lastname: Metz
mesh_terms: D000818:Animals; D001007:Anxiety / Q000503:physiopathology; D001786:Blood Glucose / Q000502:physiology; D056651:CA2 Region, Hippocampal / Q000473:pathology / Q000503:physiopathology*; D002452:Cell Count; D003345:Corticosterone / Q000097:blood; D004644:Emotions / Q000502:physiology; D005106:Exploratory Behavior / Q000502:physiology; D008297:Male; D018782:Maze Learning / Q000502:physiology; D009043:Motor Activity / Q000502:physiology*; D009474:Neurons / Q000473:pathology / Q000502:physiology; D009483:Neuropsychological Tests; D009929:Organ Size; D017208:Rats, Wistar; D013037:Spatial Behavior / Q000502:physiology; D014465:Ultrasonics; D014828:Vocalization, Animal / Q000502:physiology
chemical_list: D001786:Blood Glucose; D003345:Corticosterone
keywords: CA2; Circular tunnel task; Corticosterone; Emotionality; Hippocampus; Learning and memory; Rearing; Spatial navigation; Ultrasonic Vocalization; Vertical activity