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ABSTRACT: Introduction & Objective: The hippocampal formation is a part of limbic system that plays an important role in memory and learning. The hippocampus is divided into three subfields: CA1, CA2 and CA3. In addition to pyramidal neurons and interneurons, the astrocytes play important roles in hippocampus, probably in memory and learning. In fact, learning needs some instruments for information storage and information maintenance mechanisms like memory. On the other hand, memory is always accompanied with learning. This study was conducted to evaluate the changes in number of astrocytes in CA2 subfield of hippocampus in rats due to spatial learning. Materials & Methods: In this experimental study, with the use of Morris Water Maze and two other techniques (Reference and Working memory methods) in the behavioral laboratory of physiology department of Pasteur institute, 15 male Wistar rats were used. Five rats were included in control group and 10 rats in the other two groups (each 5 rat). After performing the educational experiments, animal brain was removed and after histological processing, the slides were stained with PTAH to show the astrocytes. The obtained data were analyzed by SPSS, using T test and variance analysis. Results: The results showed a significant difference in astrocytes number of CA2 area between control and reference memory group. Also the difference between control and working memory groups was significant. Comparing the two educated groups, a significant difference was found in the number of astrocytes in those groups. Conclusion: The number of astrocytes in CA2 area of hippocampus of rats increased due to spatial learning.

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ABSTRACT: Introduction & objective: The possible risks of radio-frequency electromagnetic fields for human body are a growing concern for our society. In the modern world, the increase of using cell phones is remarkable in all generations especially young people. In addition many users hold phone close to their head. Therefore, we have studied the effect of cell phone radiation (940 MHz) on memory and learning of Balb/C mice which were exposed after delivery. Materials & Methods: A purpose-designed exposure at a specific absorption for 3h/day from day 1 to 20 after delivery was used. Any stress response in the brain was detected in hippocampus. Behavioral performance began 2.5 month after delivery and testing was conducted in the water maze and the radial maze distinguished working and reference memory performance. After behavioral studies, fetal heads were collected, fixed in 10% paraformaldehyde and paraffine embedded. Results: Microwave-exposed mice were slower than sham-exposed, and cage control in swim speed (WM). Error Analyses rates reveal significant exposure effect in RAM and MWM. However, in this study the exposed group had not significantly lost their hippocampal CA3 neurons comparing to controls or sham exposed group. Conclusion: Increased time to locate a submerged in water maze, reference memory (entries into unbaited arms), working memory (repeated entries into baited arms), show that acute exposure to pulsed microwaves caused a deficit in spatial reference memory in the mouse. Keywords: Mobile phone, learning, memory, hippocampus

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Background &aim: Morphine sensitization can improve learning and memory formation. α-CaMKII and β-CaMKII genes which are highly expressed in the hippocampus, have an important role in learning and memory formation. This study was performed to investigate the morphine sensitization and changes in gene expression of α- CaMKII and β- CaMKII in right and left lobes of dorsal hippocampus of male rats. Methods: In this experimental study which was performed on 24 male Wistar rats, morphine sensitization was obtained by subcutaneous injection of morphine, once daily for 3 days followed by 5 days free of the opioid. Then the dorsal hippocampus was removed and RNA was extracted and cDNA was synthesized. Finally α- CaMKII and β- CaMKII genes expression was quantified using Real-Time RT-PCR. Data were analyzed using One-Way analysis of Variance and Tukey’s test. Results: The results showed that expression of α- CaMKII gene in the right and left lobe of hippocampus in morphine sensitized rats had no significant changes in comparison with the control group. Similarly under the same treatment, there was no significant changes in the right lobe of hippocampus for β-CaMKII but a significant gene expression increase was observed in the left lobe. (P<0.05). Conclusion: It seems that morphine sensitization can lead to changes in molecular mechanisms and apparently these changes can be seen differently in right and left lobes of hippocampus

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Abstract Background & aim: Almond oil contains compounds such asoleic acid, omega 3, 6, 9 polyunsaturated fatty acids and vitamin E. The aim of this study was to investigate the effects of intra-hippocampal injection of almond oil on passive avoidance learning and memory in male rats. Methods: In this experimental study, 56 male rats were randomly divided into 8 groups, including a control, 3 sailin groups which received normal saline 0.5, 1, 2 µl and 4 peanut oil groups which received 5/0, 1, 5/1 and 2 µl of oil.All groups, except the control, Groups except the control group were cannulated with stereotaxic surgery in the left CA1 region. One week after recovery, all groups were trained by shuttle box. Immediately after training, different doses of almond oil and saline were injected through the cannula in CA1 of hippocampus. After 48 hours, their Passive avoidance memory and learning were evaluated. Data were analyzed by ANOVA. Results: Almond oil doses of 0.5,1, 1.5 and 2 µg significantly improved passive avoidance learning and memory (P<0.05), but saline did not have. Conclusion: Almond oil as a steroid, effects on learning and memory and can improve learning and memory. Key Words: Learning, Memory, Almond oil, Hippocampus and Shuttle Box

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Abstract Background & aim: Soy contains the largest concentration of isoflavones, they are structurally similar to estradiol and mimic its effects. The purpose of this study was to evaluate the effect of soy milk on thickness of cerebral cortex and hippocampus in newborn ovariectomized rats. Methods: The present experimental study was conducted on 30 newborn female rats. In day 7, 20 rats were randomly chosen and ovariectomy surgery was performed on them. Then the rats were divided to six groups of five rats each: control group, ovariectomized rats (no treatment), sham group and 3 groups of ovareictomaized rats treated by soy milk in doses 0.75, 1.5 and 3 ml/kg/day. In day 60, the brains of all rats were dissected and histological studies for determination of thickness of cerebral cortex and hippocampus were done. The collected data were analyzed with one-way ANOVA and Tukey tests. Results: Our results indicated that low estradiol following ovariectomy decreased thickness of cerebral cortex and hippocampal regions and soy milk in high dose increase the levels of estradiol, thickness of cerebral cortex and thickness of hippocampal regions. Conclusion: soy milk can compensate the effect of ovariectomy on thickness of cerebral cortex and hippocampal regions. Key words: Soy Milk, Hippocampus, Cerebral Cortex

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Background & aim: Exercise enhances the synaptic plasticity and neuroprotective effects in the adult brain. However, it remains unknown that how plasticity molecules change following types of training. The purpose of this study was to determine the effect of eight weeks resistance training on protein levels of Brain Derived Neurotrophic Factor(BDNF) and receptor of TrkB, in the hippocampus of adult male rats. Methods: In this experimental study, twelve adult male rats, 8 weeks of age, with an average weight of 200 to 225 grams were randomly divided into two groups, control and exercise respectively. The exercise was to increase the weight on the ladder. 24 hours after their last training session. The animals were killed and the hippocampus was removed for further testing. ELISA determined changes in protein levels. Data were analyzed by independent t test. Results: There was a significant difference between train and control groups In protein level of variables statically (p≤0.05). In addition, protein levels of BDNF and TrkB in the hippocampus of rats increased. Conclusion: Resistance training is beneficial for promoting hippocampal plasticity associated with BDNF signaling and consequently functional and cognitive benefits.

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Backgrounds & aim: Forebrain ischemia induces complete interruption of brain blood flow and neuronal injury. In the present study the effect of Salvia rhytidia extract on cell numbers of the cerebral cortex and different hippocampal regions following ischemia-reperfusion (IR) was evaluated. Methods: In the present experimental study, Thirty-five adult male rats were divided into 7 groups of 5 rats. Control group (1), sham group (3), and 2, 4, 5, 6, and 7 as ischemic groups. (2, 4, 5, 6, 7). Left common carotid and left vertebral arteries were occluded by tourniquet for 10 min. Group 2 received no drug .sham group (3) received normal saline without ischemia. Group 4 received Salvia (3.2mg/kg) and group 5 received silymarin (50 mg/kg), 2 h after ischemia. Group 6 received the same dose of Salvia and group 7 received the same dose of silymarin 0, 24, 48, and 72 hrs before ischemia. After 24 h reperfusion, the brains of rats were prepared for histological studies. The cells were counted and cerebral and hippocampal tissue sections stained by hematoxylin and eosin. The data were analyzed by One-way ANOVA and Duncan as posthoc test. Results: Significant decrease was observed in the neural cell numbers of cerebral cortex and pyramidal layer of CA1 and CA2 regions of the hippocampus in groups 2, 4 and 5 compared to control group (p=00000). No significant decrease was observed in neural cell numbers of cerebral cortex and all hippocampal regions in groups 3, 6, 7. Pyramidal layer of CA3 and granular layer of dentate gyrus regions of the hippocampus in groups 2, 4 and 5 compared to control. Conclusion: Saliva extract with aintoxidan effect similar to silymarin protects the forebrain from ischemia injuries and reperfusion.

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Background & aim: The effect of stress on the nervous system activity may be due to alterations in the structure of the nervous system. In this study, the effects of maternal stress was examined on the seizure threshold and hippocampal structure of their offspring during pregnancy. Methods: In this study, thirty pregnant mice were divided into two groups. 1) No stress group and 2) Stress group that received one hour immobilization stress from 1 to 14 day of pregnancy. The seizure threshold test was performed in offspring by injection of Pantilen tetrazol (PTZ). To study of the hippocampus development, the mouse offspring were divided into three groups: The control group no received immobilization stress on pregnant rat and their offspring also no received PTZ. The Sham group no received immobilization stress on pregnant rat but their offspring received PTZ. and experimental group that pregnant rat received immobilization stress and their offspring received PTZ. At the end of the experiences, all offsprings were killed by chloroform and their hippocampus fixed in and processed and 5µm sections were prepared and stained by the H&E method. The pyramidal and granular layers thickness in the Hippocampus were measured using Motic software and the number of cells in these layers and the number of blood vessels in the molecular and polymorphic layers were counted. The data were analyzed using ANOVA and T test. Results: The results showed a significant increase in seizure threshold in offspring whose mothers were under stress, compared with offspring whose mothers were not under stress. Average thickness of hippocampal pyramidal and granular in the experimental group than in the control group showed a significant increase (p<0.001). in addition, mean thickness of pyramidal and granular layers of hippocampus significantly increased in the experimental group compared to control group. The number of cells in hippocampal and granular layers significantly decreased in the experimental group when compared with control and sham groups (p<0.001). Conclusion: Prenatal stress can cause an increase in seizure threshold and also impair offspring's development and their hippocampal structure.

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Introduction: The Valeriana officinalis has therapeutic properties in neurological disorders, insomnia and hysteria. Thus, we evaluated the protective activity of Of ethanol extract of this plant on the proliferation and diameter of astrocytes in the hippocampus. Materials and Methods: In this experimental study, forty Sprague Dawley rat (200–230 g) were randomly divided equally into 4 groups, in which the control group received distilled water. The treatments groups I, II and III received Valeriana officinalis extracts 300, 400 and 600 mg/kg respectively, daily for three weeks. Then, the rats were killed and brain were removed and fixed. The numbers and large diameter of the astrocytes cells were measured in the hippocampus of different groups. Results: The mean numbers of astrocytes of the CA1 and CA2 in the group that received 600 mg/kg of Valeriana officinalis extracts were 16.79±6.48 and 9.11±3.91 respectively, which significantly increased compare to the control group. The mean of large diameter of astrocytes in the CA1 region of the animals with 300, 400 and 600 mg/kg of Valeriana officinalis were 10.41±2.87, 7.85±2.36 and 5.5±2.06 respectively, that decreased significantly compare to the control group 13.1±4.01. Conclusion: The Valeriana officinalis extract with antioxidant property has potential to proliferate the astrocytes cells in the hippocampus.

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Background & aim: Diabetes is a metabolic disorder characterized by hyperglycemia. Hyperglycemia through enzymatic and non-enzymatic processes causes induction of spontaneous oxidation of glucose and, by stimulating the production of active oxygen and nitrogen components, leading to oxidative stress. Thus, according to the antioxidant effects of atorvastatin and zinc oxide, the aim of this study  was to investigate the combined effect of atorvastatin and zinc oxide on oxidative stress and antioxidants in diabetic rats.

Methods: In the present experimental study, 50 female Wistar rats were selected randomly and divided into five groups of 10 (n=10) including : normal control (NC), diabetic control (DC), diabetic rats treated with, atorvastatin (20mg/kg daily-orally) (DA), zinc oxide (30mg/kg daily-rally) (DZ) and combination of each drug in half-dose (daily-orally) (DAZ), were each treated separately. Diabetic rats were induced by injection of 60 mg per kg of body weight of streptozotocin (STZ) intraperitoneally.All treatments were dissolved in distilled water for four weeks. After completion of treatment (forth week), weight and blood sugar were measured and then compared with data measured  on weight and blood sugar in the weeks before the start  and second week of the study. The lipid peroxidation level (MDA), the activity of catalase (CAT) and total antioxidant capacity (TAC) as an indicator of oxidative stress were measured in the hippocampus. Data were analyzed using ANOVA and Tukey tests.

Results: Zinc oxide and atorvastatin alone rather than decrease blood sugar, reduced the complications of diabetes, including oxidative damage and combination  of both reduced levels of diabetic complications led to the significant decrease in blood glucose levels and inhibiting the animal lose weight.

Conclusion: It seemed that the combination of atorvastatin and zinc oxide have synergistic benefits to control blood sugar levels and oxidative stress, and also resulting in control  of diabetes.

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Background & aim: Due to the toxic effects of lead at low levels which causes several disorders, such as weakness, impaired ability and behavioral thinking and children's learning, loss of hearing and vision, damage to cerebellum gray cells and brain hippocampus. The purpose of this study was to evaluate the protective role of wheat germ in controlling oxidative stress and tissue damage of lead-exposed brain hippocampus.
 
Methods: In the present experimental study, 30 female Wistar rats (240 ± 20 g) were divided into 6 groups: control (without treatment), treat with 10 mg lead, wheat germ extract with 100 and 200 mg, synchronous lead and wheat germ extracted at doses of 100 and 200 mg. On the 36th day, the mice were killed and their brain were dissected. After the stabilization of the samples, the dewatering, clarifying, and molding processes took place. The molds were cut in a thickness of 5-7 micrometers and stained with H & E. The collected data was analyzed by one-way ANOVA and Tukey's test.
 
Results: A significant differences was observed in the treatment group regarding the number of pyramidal cells in CA1, the number of granulary granulomatous cells in the teeth and the thickness of the vaginal layers of the teeth compared to the control group.On the other hand, at concentration of 20 mg lead group, the 20 mg lead group with 100 mg of wheat germ, the number of pyramidal cells in CA1 and the number of cells and the thickness of the granular ventricular layer of the teeth were significantly different compared to the other groups.  No significant difference was observed in the thickness of the teething tubes, the number of pyramidal cells in CA1 and granular layer cells, and the weight of the mice in all groups at dose of 20 mg lead and gram wheat germ wheat extract 100 and 200 mg compared to the control howerer, the weight of the brain in all groups was significantly higher than the control group.
 
Conclusion: According to the findings of the present study, the use of wheat germ extracts due to the oxidative anti stress effect could be effective in improving the lesions induced by lead on the rat's hippocampus. Wheat germ extract had the ability to compensate for lead-induced lesions in the hippocampus, which depends on the dose administered.
 
 

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Background & aim: Acute attacks of epidemics and the physical risk have severe adverse psychological side-effects on post covid patients. Most importantly, COVID-19 survivors who experienced fear for survival are vulnerable to post-traumatic stress symptoms. The present study aimed to determine effectiveness of online compassion-focused therapy in reducing the severity of post-traumatic stress symptoms, increasing post-traumatic growth and studying the changes in hippocampus and amygdala volume in recovered patients infected with the corona virus in Shiraz and in It was done in 1401.

Methods: The present study was conducted between May 2021 and July 2022 among patients with delta variant COVID-19 in Fars province, Iran. The study’s statistical population included 40 patients with hospitalized history on delta variant (Covid-19) diagnosed with post-traumatic stress symptoms, who were purposefully sampled in two experimental groups (40 people) and control groups (20 people). The control group received standard treatment during this period. Inclusion criteria were not having specific mental disorders, being literate in reading and writing, suffering from corona disease.  Exclusion criteria were not fully attending Psychotherapy classes, having a mental disorder. The participants responded to the Tedeschi and Calhoun's post-traumatic growth and development questionnaire, PCL-5 post-traumatic stress disorder questionnaire. The researchers measured the volumes of hippocampus and corpus amygdaloideum (amygdaloid body), The 1.5 T MRI was taken at oblique coronal plane using a section thickness of 3 mm without any gap. The researchers correspondingly investigated right-left volume differences for hippocampus and corpus amygdaloideum. For data analysis, multivariate analysis of covariance, univariate analysis of covariance, mean and standard deviation were used.

Results: it was indicated thatSelf-compassion psychotherapy had a significant effect on post traumatic growth (p<0.001, F=62.548) and reducing post-traumatic stress (F=103.335, p<0.001). Furthermore, the volume of the hippocampus and amygdala of the compassion therapy group increased in the post-test phase (F=21.995, p<0.001).

Conclusion: Psychosocial interventions that promote more informed and organized rumination about the pandemic and enhance posttraumatic growth in response to prior traumatic events can help facilitate positive psychological changes associated with the COVID-19 pandemic in post-chronic patients. slow down and also planning psychotherapy strategies in crises through telemedicine and online services should be taken into consideration.