title: Short-term exposure to enriched environment rescues chronic stress-induced impaired hippocampal synaptic plasticity, anxiety, and memory deficits.
abstract: Exposure to prolonged stress results in structural and functional alterations in the hippocampus including reduced long-term potentiation (LTP), neurogenesis, spatial learning and working memory impairments, and enhanced anxiety-like behavior. On the other hand, enriched environment (EE) has beneficial effects on hippocampal structure and function, such as improved memory, increased hippocampal neurogenesis, and progressive synaptic plasticity. It is unclear whether exposure to short-term EE for 10 days can overcome restraint stress-induced cognitive deficits and impaired hippocampal plasticity. Consequently, the present study explored the beneficial effects of short-term EE on chronic stress-induced impaired LTP, working memory, and anxiety-like behavior. Male Wistar rats were subjected to chronic restraint stress (6 hr/day) over a period of 21 days, and then they were exposed to EE (6 hr/day) for 10 days. Restraint stress reduced hippocampal CA1-LTP, increased anxiety-like symptoms in elevated plus maze, and impaired working memory in T-maze task. Remarkably, EE facilitated hippocampal LTP, improved working memory performance, and completely overcame the effect of chronic stress on anxiety behavior. In conclusion, exposure to EE can bring out positive effects on synaptic plasticity in the hippocampus and thereby elicit its beneficial effects on cognitive functions. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India.
authors.forename: Venkanna Rao
authors.initials: VR
authors.lastname: Bhagya
authors.affiliation: Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India.
authors.forename: Bettadapura N
authors.initials: BN
authors.lastname: Srikumar
authors.affiliation: Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India.
authors.forename: Jayagopalan
authors.initials: J
authors.lastname: Veena
authors.affiliation: Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India.
authors.forename: Byrathnahalli S
authors.initials: BS
authors.lastname: Shankaranarayana Rao
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001007:Anxiety / Q000209:etiology / Q000451:nursing*; D004195:Disease Models, Animal; D004558:Electric Stimulation; D004777:Environment; D006624:Hippocampus / Q000503:physiopathology*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000502:physiology; D008297:Male; D018782:Maze Learning; D008569:Memory Disorders / Q000209:etiology / Q000451:nursing*; D008570:Memory, Short-Term / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013315:Stress, Psychological / Q000150:complications / Q000473:pathology*
keywords: chronic stress; environmental enrichment; hippocampus; synaptic plasticity; working memory