title: Stress enhances return-based behaviors in Wistar rats during spatial navigation without altering spatial performance: improvement or deficit?
abstract: Stress is frequently reported to be deleterious to spatial learning and memory. However, there are many instances in which spatial performance is not affected by stress. This discrepancy observed across different studies, in addition to the animals' strain and gender, may be caused by the type of the task employed to assess stress-related behavioral changes. The present experiments set out to investigate the effects of repeated restraint stress (3h/21 days) on spatial performance within the two wet-land (Morris water task; MWT) and dry-land (the ziggurat task; ZT) tasks for spatial learning and memory in adult male Wistar rats. All rats were tested before and after stress treatment. Stressed rats gained less weight than controls. Stress also enhanced circulating corticosterone (CORT). We did not observe a deleterious effect of stress on spatial learning and memory in either of the tasks: both groups successfully performed the wet- and dry-land tasks across all spatial testing days, indicating intact spatial cognition in control and stress rats. However, daily restraint stress for 21 days significantly caused enhancement in rats' memory-dependent returns during the goal-directed investigation in the ZT. The number of returns on learning days was not affected by repeated restraint stress. Return-based spatial investigation induced by stress only on memory days in the dry-land task, not only emphasize on the task-dependent nature of stress-related alterations, it may reveal one of the silent, but arguably deleterious effects of stress on spatial memory in Wistar rats.
authors.affiliation: Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada; Golestan University of Medical Sciences, Faculty of Nursing & Midwifery, Gorgan, Islamic Republic of Iran. Electronic address: jamshid.faraji@uleth.ca.
authors.forename: Jamshid
authors.initials: J
authors.lastname: Faraji
authors.forename: Seyyed Yaghoob
authors.initials: SY
authors.lastname: Jafari
authors.forename: Nabiollah
authors.initials: N
authors.lastname: Soltanpour
authors.forename: Kaveh
authors.initials: K
authors.lastname: Arjang
authors.forename: Nasrin
authors.initials: N
authors.lastname: Soltanpour
authors.forename: Reza
authors.initials: R
authors.lastname: Moeeini
mesh_terms: D000818:Animals; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical; D013028:Space Perception / Q000502:physiology*; D013037:Spatial Behavior / Q000502:physiology*; D013312:Stress, Physiological / Q000502:physiology*; D013315:Stress, Psychological / Q000503:physiopathology*
keywords: Memory; Restraint stress; Return; Spatial performance; Ziggurat task