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Background and Objective: Ischemia-reperfusion invoke cell death in hippocampus. This study was carried out to investigate the effect of transforming growth factor alpha (TGF-alpha) of dentyte jyrus neurons and pyramidal cells of CA1 subfiled of hippocampus following ischemia-reperfusion in rat models. Materials and Methods: This experimental study was done on 40 male Wistar rats weighing 250-300gr. Animals were divided in four groups: control (n=7), sham (n=7), ischemia (n=14) and treatment (n=14). Sham group was just under surgical stress. In ischemia and treatment groups after induction of ischemia-reperfiusion by obstruction of carotid arteries blocked for 30 minutes, reperfusion PBS (phosphate buffer salin) and subsequently TGF-alpha (50 ng) were injected stereotaxicaly in lateral ventricle, respectively. In 12 and 72 days after treatment the brains were fixated by transcardial perfusion and stained by immunohistochemestry and nissle methods. Furthermore, morris water maze was used to evaluate the learning memory. Data were analyzed using SPSS-16 and ANOVA test. Results: Injection of TGF-alpha increased the cell number in hippocampus of treatment group compared to ischemic group. TGF-alpha increased expression of neuron in dentyte jyrus of treatment group in comparison with ischemic group (P<0.05). Also spatial memory improved in treatment group in comparison with ischemia group. Conclusion: TGF-alpha improves ischemia-induced neurodegenration and memory impairment.

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Background and Objective: Post-traumatic stress disorder (PTSD) impairs spatial learning and memory. Desmopressin acetate ameliorates the cognitive deficits induced by electroconvulsive shock. This study was designed to evaluate the protective effects of Desmopressin acetate on retention of spatial memory deficits induced by post-traumatic stress disorder in rats. Materials and Methods: In this experimental study twenty one male Wistar rats were used. Animals were trained for 5 consecutive days in Morris water maze and then were randomly assigned in three groups (Vehicle + Sham, Saline + PTSD and Desmopressin acetate + PTSD) and tested in a probe 60 sec in 24h after the last acquisition trial. The groups of PTSD+Desmopressin acetate rats and vehicle+sham, saline+PTSD were injected Desmopressin acetate (10 micro gr/kg body weight) and saline (IP), respectively. Injections performed ten minute prior to PTSD and spatial memory was tested ten minutes later. Data were analyzed using SPSS-16, One-Way ANOVA and Tukey tests. Results: The platform location latency of the Desmopressin acetate+PTSD group was significantly shorter (4.24 sec) than the control group (P<0.05) and also, had significantly smaller average proximity values (33.87 cm) compared to the saline+PTSD group (P<0.05). Desmopressin acetate + PTSD spent significantly more time (21.65%) in the target zone (P<0.05). Conclusion: This study indicated that Desmopressin acetate blocks the ability of PTSD to impair spatial memory retention.

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Background and Objective: Stem cells are a suitable treatment method for improvement of central nervous system diseases. Neuron regeneration is occure in damaged region using stem cell transplantation. This study was done to determine the effect of bone marrow mesenchymal stem cells on memory and neuronal cells graft number in the trimethyltin chloride damaged hippocampus. Methods: In this experimental study, 28 wistar male rats were allocated into four groups including control, model, Vehicle and treatment groups. Animals were received 8 mg/kg/bw of neurotoxin trimethyltin chloride by the intraperitoneal injection for causing damaged in hippocampus. One week after intraperitoneal injection of trimethyltin chloride, stem cells was injected by stereotaxy method. Six weeks after stem cells injection, the spatial memory was assessed by Morris water maze and histological studies were done by Nissl staining and normal cells count by Olysia bio report software. Results: After bone marrow mesenchymal stem cells graft, the number of normal cells were more in the treatment group (74±15.190) in compared to the Vehicle (44.67±12.971) and Model (48.56±18.105) groups (P<0.05). Also in Morris water maze test, the treatment group (387.35±189.18), (31.30±13.67) spent shorter distance and escape latency to reach the hidden platform, but this reduced non significantly in compared to Vehicle (438.18±192.56), (40.14±14.89) and model (407.98±225.44), (37.68±17.15) groups. The model and Vehicle groups spent longer distance to reach the hidden platform in comparision with the control (275.45±165.10) group (P<0.05). Also the traveled distance in target quarter had significant increased in the treatment groups (799.80±125.91) in compared to model (588.51±136.94) and Vehicle (546.48±86.47) groups (P<0.05). Conclusion: Using the bone marrow mesenchymal stem cells leads to reduce hippocampal lesions and increase the number of pyramidal neurons and improving memory in damaged hippocampus in animal model.

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Background and Objective: Tamoxifen is one of the selective estrogen receptor modulators that exerts estrogen / anti-estrogen effects in various tissues. This study was done to evaluate the effect of chronic administration of tamoxifen on spatial memory and passive avoidance task in adult male Wistar rats.

Methods: In this experimental study, 48 adult male Wistar rats were randomly divided into control, sham and tamoxifen groups. Animals in sham and tamoxifen groups were received tamoxifen solution and tamoxifen (400mg/kg/day) orally for 35 consecutive days. At the end of treatment, spatial learning and memory of animals was assessed using the Morris water maze task and passive avoidance memory was examined using the shuttle box.

Results: The time spent and distance moved to reach the platform, significantly increased in tamoxifen group compared to controls (P<0.05). In addition, the time spent and distance moved in the target quadrant (in the probe test) significantly reduced in tamoxifen group in compared to controls (P<0.05). In passive avoidance task, tamoxifen significantly decreased the time of the entrance to the dark room compared to control animals (P<0.05).

Conclusion: Long-term administration of tamoxifen impairs spatial learning and memory and passive avoidance memory in rats.

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Background and Objective: Oxidative stress causes disorder in the brain processes including memory. Pistacia atlantica kurdica (pistachio) contains antioxidant compounds, oleic and linoleic acid. Fluvoxamine is an antidepressant medicine which inhibits serotonin reuptake. This study was done to determine the effect of hydroalcoholic extract of pistachio and fluvoxamine on spatial memory of male rats under immobilization stress.
Methods: This experimental study was done on 30 adult male Wistar rats in 5 groups (n=6). The control group was not under immobilization stress. Animals in the stress group were just under immobilization stress. Animals in the pistachio group were under immobilization stress and were received 400 mg/kg/bw hydroalcoholic extract of pistachio. Animals in the fluvoxamine group under immobilization stress were received 120 mg/kg/bw fluvoxamine. Animals under immobilization stress, in the pistachio plus fluvoxamine group were received 400 mg/kg/bw hydroalcoholic extract of pistachio and fluvoxamine 120 mg/kg/bw. The radial arm maze test was used for evaluation of spatial memory. After the animals’ decapitation, the malondialdehyde and catalase level in hippocampus and the serum level of corticosterone and blood glucose were measured.
Results: The stress significantly increased the time of reaching to target, malondialdehyde, corticoestron and blood glucose level, and reduced the catalase in stress group in comprasion with controls (P<0.05). In the pistachio and the pistachio+fluvoxamine treated groups, the time of reaching to target, malondialdehyde, corticoestron and blood glucose level significantly reduced and the catalase level significantly increased in comprasion with stress group (P<0.05) but fluvoxamine significantly increased the time of reaching to target, malondialdehyde and blood glucose, and reduced the corticoestron and catalase in compared to controls (P<0.05).
Conclusion: The immobilization stress led to attenuation of spatial memory and the fluvoxamine administration as an antidepressant drug caused to deterioration of memory,while the treatment with pistachio extract lead to improve the memory.

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Background and Objective: Atorvastatin is a member of the statin family with lipophilic character and anti-hyperlipidemic effect. There is many evidence that atorvastatin has protective effect on cognitive function. This study was done to evaluate the effect of atorvastatin on spatial memory in rats following a high-fat diet.
Methods: This experimental study was performed on 35 male Wistar male rats. Animals were randomly allocated into 5 groups including control, control plus atorvastatin and sham (received high-fat diet for 4 weeks) and high-fat diet plus atorvastatin (10 and 50 mg/kg, for 4 weeks). Learning and spatial memory were measured using Morris water maze for a 6-day period including 5 days training and the last day, test day (probe day).
Results: High-fat diet reduced learning and poor memory performance during training and probe compared to the control group, and also on the probe day, the high-fat group spent less time in the target quarter (P<0.05). Administration of atorvastatin after a high-fat diet improvement spatial memory in compared to high-fat group (P<0.05).
Conclusion: Short-term treatment (4 weeks) with atorvastatin in high-fat dietary rats can improve spatial memory.

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Background and Objective: Alzheimer is the most common form of dementia in elderly persons. Oxidative stress is one of the main pathological factors in Alzheimer’s disease. This study was done to investigate the effect of crosin on histological changes of hippocampus and memory impairment which induced by scopolamine in the male rats.
Methods: In this experimental study, 30 male rats were randomly allocated into 3 groups including: control, scopolamine and scopolamine with crosin treated groups. Scopolamine with dose of 3 mg/kg/bw for one week and crocin with dose of 30mg/kg for two weeks were administered, intraperitoneally. The learning and spatial memory parameters were evaluated by Morris water maze test. Then the animals were sacrificed and their hippocampi were removed immediately for histological evaluation.
Results: Scopolamine injection causes significantly increased the number of dark cells in CA1 region of hippocampus in compared to control group (P<0.05). Treatment with crocin decreased dark cells and increased light cells number in CA1 region of hippocampus (P<0.05). Also treatment with crocin decreased memory impairment that induced by scopolamine in rats (P<0.05).
Conclusion: It seems that treatment with crocin has protective effects against neuronal damage of CA1 region of hippocampus and memory impairment that induced by scopolamine.