title: Enriched environment improves synaptic plasticity and cognitive deficiency in chronic cerebral hypoperfused rats.
abstract: Recent studies have indicated that environmental enrichment (EE) increases the sensorial and social stimulations and leads to strengthened plastic changes in the brain. In models of chronic cerebral hypoperfusion, the ability of an EE to restore the cognition depends on hippocampal synaptic plasticity. The mechanisms for this effect have not, however, been adequately studied. Thus, the aim of the present study was to evaluate the neuroprotective effects and underlying mechanism of environmental enrichment by assessment of spatial memory tasks as well as parameters of synaptic plasticity in rats subjected to occlusion of the bilateral common carotid arteries (2-VO) model. Male Sprague-Dawley rats were used in this study. The model group was established by occlusion of the bilateral common carotid arteries. The animals were tested for learning, memory performance and synaptic plasticity using Morris water maze (MWM), 8-arm Radial Maze (RM), and field potential recording, respectively. The rats subjected to 2-VO in EE exhibited a significantly lower number of working errors and reference errors in RM. Moreover, the enriched environment recovered the memory performance of hypoperfused rats and decreased the swimming time to reach the platform in MWM. In addition, conditions of the environment did not have any effect on baseline synaptic transmission and presynaptic plasticity, but housing the animals in EE rescued the impairment of LTP induction induced by 2-VO. These results suggest that EE ameliorates the LTP and spatial memory impairment induced by 2-VO. Our data indicated that the LTP recovery by EE in the rat models of 2-VO is probably mediated by post-synaptic mechanisms.
authors.affiliation: Department of Physiology, International Branch, Shiraz University of Medical Sciences, Shiraz, Iran. Electronic address: mbayat53@yahoo.com.
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Bayat
authors.affiliation: Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. Electronic address: davoodsharifi57@yahoo.com.
authors.forename: Mohammad Davood
authors.initials: MD
authors.lastname: Sharifi
authors.affiliation: Histomorphometry and Stereology Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Physiology, Shiraz University of Medical Sciences, Shiraz, Iran. Electronic address: haghani55@yahoo.com.
authors.forename: Masoud
authors.initials: M
authors.lastname: Haghani
authors.affiliation: Kerman Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran. Electronic address: shabanimoh@yahoo.com.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shabani
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000503:physiopathology* / Q000628:therapy*; D002340:Carotid Artery Diseases; D017536:Carotid Artery, Common; D003072:Cognition Disorders / Q000503:physiopathology* / Q000628:therapy*; D004195:Disease Models, Animal; D004777:Environment; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D006624:Hippocampus / Q000503:physiopathology; D006799:Housing, Animal; D008297:Male; D018782:Maze Learning; D008839:Microelectrodes; D009473:Neuronal Plasticity / Q000502:physiology*; D011897:Random Allocation; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D065852:Spatial Memory
keywords: Brain ischemia; Electrophysiology; Enriched environment; Field potential recording; LTP