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Showing 11 results for Moazedi

Moazedi, Hovayda, Rasekh,
Volume 7, Issue 1 (Spring and Summer 2003)
Abstract

Estrogen has a widespread and complex influence on brain capabilities such as learning and memory. On the other hand, hippocampus as one of the main brain structures has an important role in spatial information processing. There is some evidence on the existence of estrogen receptors in the hippocampal CA1 area. So, in this study the effect of intrahippocampal injection of estradiol benzoate on spatial learning and memory were investigated in intact and castrated adult male NMRI rats The animals were randomly divided into eight groups and bilaterally cannulated (n=7). The intact and castrated control groups (no injection) were trained in Y-maze. The castrated and intact rats received sesame oil vehicle, sham physiological saline and estradiol. Test groups received bilaterally 0.5 µl of sesame oil, 0.5 µl of physiological saline, and 1 µg/0.5 µl of estradiol benzoate respectively into the CA1 region of hippocampus immediately before training. Then, each rat was trained in 30 trials every day for a total of 5 days with Y-maze. After one month, all of the groups were again tested for memory performance. Statistical analysis of data showed that estradiol increases spatial learning in castrated and intact groups. There was also no significant difference between castrated and intact groups regarding memory performance. In conclusion, it seems that estradiol increases spatial learning task through an interaction with cholinergic system an enhancement of synaptic plasticity in CA1 region.
Zohreh Ghotbeddin, Ahmad Ali Moazedi, Gholam Ali Parham,
Volume 11, Issue 2 (Summer 2007)
Abstract

Introduction: Aluminum is known as a neurotoxic element which causes neurodegeneration, learning deduction and movement disorders. Aluminum ions in the brain cause serious problems such as Alzheimer, Parkinson and other degenerative diseases. On the other hand, Zinc is a dietary element essential for several biological processes, modulates neurotransmission in brain regions and associates with cognition. Apoptosis plays a role in many neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease. Imbalances of this metal, either excess or deficiency, can result in neuronal apoptosis. Here we have studied the effect of their co-administration on memory and motor activity. Methods: Zinc chloride (30 mg/kg/day) and aluminum chloride (600 mg/kg/day) were co-administered in drinking water of male rats for two weeks. Two criteria were assessed in behavioral tests: latency to enter and time spent in dark. Motor resistance and coordination were evaluated in movement studies. Results: Experiments showed that following 2 weeks co-administration of ZnCl2 (30 mg/kg/day) and AlCl3 (600 mg/kg/day), passive avoidance memory and motor coordination have been improved (P<0.001). Conclusion: Results suggest that zinc chloride consumption with (30 mg/kg/day) dose, could have a significant effect on memory and motor coordination and could prevent the negative effect of AlCl3 on learning, memory and motor activity. Different mechanisms such as modulation of NMDA receptors and modulation of the entry of aluminum into the brain may be potentially involved in the observed effect of zinc..
Mahmoud Aminizadeh, Mehdi Abbasnejad, Ahmad Ali Moazedi, Ahmadali Papahn,
Volume 12, Issue 1 (Spring 2008)
Abstract

Introduction: Previous studies have shown that vitamin A and its derivatives such as retinoid and all-trans retinoic acid have a crucial role in memory, learning and synaptic plasticity. The receptors of vitamin A are seen in different parts of the brain such as hippocampus, where vitamin A has an important role in learning. In this study, the effect of intrahippocampal (CA1) injection of all – trans retinoic acid on spatial learning was investigated in adult male rats. Methods: 49 adult male rats divided in 7 groups were used. Test groups (1 – 4) received 1μl of all – trans retinoic acid dissolved in DMSO at concentrations of 1, 2, 4 and 8 μg/μl, for 4 consecutive days, 90 minutes before training. Group 5 received DMSO and 6th and 7th groups were designated as sham operation and control (intact) group, respectively. After each injection, Morris Water Maze (MWM) was used as a method to measure learning task. Results: This study showed that all – trans retinoic acid at the concentration of 1 μg/μl improved spatial learning in Morris Water Maze (p< 0.05). Conclusion: Our findings show that all – trans retinoic acid improves spatial learning in rats via enhancing the expression of learning related proteins.
Zohreh Valizadeh, Ahmad Ali Moazedi, Gholamali Parham,
Volume 12, Issue 3 (Fall 2008)
Abstract

Introduction: Zinc is an essential trace element that plays an important role in synaptic plasticity and modulating the activity of CNS and involve in learning and memory. Synaptic vesicle zinc in the hippocampus area exerting modulatory effects on NMDA glutamate receptor. Method: In this experiment the effects of NMDA agonist and antagonist administration intra hippocampus on passive avoidance learning and memory in adult male rats in presence and absence of Zncl2 by step down task has been investigated. Animal divided into 10 group (n=8).Control group, second group received 0.1µg/rat NMDA in 1µlit saline for 4 days. Sham group received saline in the same volume. Forth group received 1µg/rat MK-801 in 1µlit saline 10min before training for 4 days. Sham group received saline in the same volume. Five remain groups received 30mg/kg/day zncl2 in drinking water for 2 weeks. Sixth groups only received 30mg/kg/day zncl2, but others groups (7, 8, 9, and 10) in addition consumption zncl2 received drug and saline in the same condition to 2,3,4,5 groups. Result: our experiment showed that consumption of 30mg/kg/day zncl2 impair learning and memory in adult male rats (P<0.05), while administration of NMDA improve the impairment effects on zncl2 consumption (P<0.05), but administration of MK-801 increasing the impairment effects of zncl2. Concultion: It seems that zinc impaired passive avoidance learning and memory by effects on subunits of NMDA receptor in hippocampus.
Somaieh Khosravani, Ahmad Ali Moazedi, Seyed Reza Fatemi Tabatabaee, Seyed Reza Fatemi, Mohamad Reza Zadkarami,
Volume 14, Issue 2 (Summer 2010)
Abstract

Introduction: Zinc is an essential rare element that plays an important role in synaptic plasticity and modulation of the activity of central nervous system and is involved in learning and memory. Increasing zinc intake may protect against conditions associated with zinc deficiency, such as diabetes. Some studies have revealed that zinc deficiency in diabetic subjects is due to hogher excretion or lower absorption of zinc in these subjects. Therefore, in this study, effects of various doses of zinc chloride on passive avoidance task was investigated in adult male Wistar rats without zinc deficiency. Methods: Male Wistar rats (200±20g) with streptozotocin-induced diabetes were used in this study. Rats were randomly divided into the groups that received ZnCl2 (30,50,70,100 mg/kg/day) or the same volume of water (diabetic healthy control group) by oral gavage for two weeks. Each rat was then tested by Step-Down device once daily for 4 days. Memory, which was measured by the time that a rat stays on the stone bench, was measured 24h after the last trial (5th day). Results: The results showed that the use of ZnCl2 (30, 50, 70,100 mg/kg) for 2 weeks did not significantly affect passive avoidance learning and memory. Conclusion: These results indicate that ZnCl2 with doses that were administered in this study, does not remarkably affect learning and memory process. This is probably because streptozotocin-induced diabetic rats have zinc deficiency and they require higher doses of zinc supplementation for compensation of zinc loss due to hyperzincuria
Ahmad Ali Moazedi , Marzieh Moosavi, Rahim Chinipardaz,
Volume 14, Issue 4 (Winter 2011)
Abstract

Introduction: Estrogen is one of the gonadal hormones that has multiple beneficial actions in central nervous system and involves in learning and memory. Alzheimer's disease (AD) is a progressive neurodegenerative disorder that impairs patient memory. The human nucleus basalis of Meynert (nBM) is severely affected in Alzheimer's disease. So in this study the effect of peripheral (intramuscular) injection of estradiol banzoate on passive avoidance memory was investigated in adult male wistar rats. Methods: nBM bilateral electrical lesion rats were divided in to control, lesion, sham (lesion+ 0.2ml sesame oil) and estradiol treatment (lesion+ 0.2, 0.4, 0.8, 1.2 mg/kg). After injection estradiol or sesame oil (vehicle) each rat was trained by shuttle box one week. In this study two factors, latency in entering dark chamber and time spending in the dark chamber was considered. Results: Statistical analysis showed that nBM bilateral lesion decrease the passive avoidance memory (P<0.01). Injection 0.2mg/kg estradiol does not improve memory. While injection 0.4 and 0.8mg/kg estradiol have improved memory (p<0.05, p<0.01). But injection 1.2 mg/kg estradiol does not have distinctive effect on passive avoidance memory. Conclusion: Estradiol benzoate affects passive avoidance memory in a dose dependent manner. It seems that estrogen improve memory through an interaction with cholinergic system via genomic and non-genomic mechanisms.
Neda Asliranifam, Hossein Najafzadeh, Ahmad Ali Papahn, Ahmad Ali Moazedi, Mahdi Pourmahdi,
Volume 15, Issue 2 (Summer 2011)
Abstract

Introduction: Previous studies have shown that sesame oil affects memory and learning. In the present work, effect of a diet containing 10% sesame oil used during pregnancy was evaluated on short-term passive avoidance learning of offspring rats by Shuttle box. Methods: Female Wistar rats were divided into 2 groups (n = 9 each group). Control group consumed regular diet during pregnancy and the treatment group received a diet containing 10% sesame oil. Male and female offspring were examined on the 30th day of their ages. Results: Passive avoidance learning of offsprings that their mother received sesame oil during pregnancy was significantly increased in comparison to the control group. Conclusion: The results show that consumption of a diet containing 10% sesamin oil during pregnancy significantly increases short -term passive avoidance learning of offspring.
Hoda Parsa , Ahmad Ali Moazedi , Lotfolah Khajehpour, Mehdi Pourmehdi,
Volume 16, Issue 2 (Summer 2012)
Abstract

Introduction:The hippocampus is one for the major centers of learning and memory. Role of the opioid system has been investigated and on the other hand receptors related to this system such as mu-opioid receptors (MOR) are extended in the hippocampus. In this study the effect of Naloxone administration as a mu opioid receptor antagonist on passive avoidance memory in adult male rats was investigated by using shuttle box instrument. Methods:Methods: In this study 45 male adult Wistar rats at range of 200± 20 were used. They were cannulated after anesthesia and Naloxone 0.5, 1, 1.5 and 2 µg/rat has been injected intrahippocampally after recovery and post training by shuttle box .Then after 90 minute short –term memory and after 24 hours long- term memory were measured posttrainingly. Results:results showed that naloxone0.5, 1, 1.5 and 2µg/rat didn’t affected short – term memory on the other hand according to results of long-term memory showed that Naloxone 0.5 µg/rat didn’t affected memory and Naloxone 1 and 1.5 µg/rat improved memory and Naloxone 2 µg/rat impaired memory. Conclusion:Considering to obtained results it seems that Naloxone affected learning and memory in a dose dependent manner.
Seyedeh Parisa Navabi, Ahmad Ali Moazedi, Hooman Eshagh Harooni, Lotfolah Khajeh Pour,
Volume 17, Issue 2 (Summer 2013)
Abstract

Introduction: Dexamethasone is a synthetic glucocorticoid with possible effects on anxiety and depression because it has direct effects on the hypothalamus-pituitary-adrenal (HPA) and interacts with several neurotransmitter systems such as GABA and glutamate. Methods: Levels of anxiety and depression in rats were measured 40 minutes and 24 hours, respectively, after subcutaneous injection of Dexamethasone Sodium-Phosphate (DEX) 0.5, 1, 5, 10, 20, 30 mg/kg (saline 1ml/kg) in the elevated plus maze and forced swimming test. Results: The results of anxiety test showed a significant decrease in the percentage of open arm time and open arm entries in DEX (1 mg/kg) group compared to the saline groups. The percentage of time spent in the open arms significantly increased in DEX (20mg/kg) compared to the saline group. In terms of locomotor activity (total number of open and closed arms), significant decrease was observed in DEX (1 mg/kg) compared to the saline group. Also, a significant difference between DEX 1 and 20 mg/kg groups was observed. Comparative assessment of depression during total immobility time showed significant increase in DEX (1 mg/kg) compared to saline and also a significant decrease was observed in DEX (30 mg/kg) compared to the saline groups. A significant difference in latency to immobility was also detected between DEX 1 and 30 mg/kg groups. Conclusion: Our findings suggest that administration of DEX induced dual effects on anxiety and depression anxiogenic and depressant effects were observed at lower doses, while anxiolytic or antidepressant effects were detected at higher doses.
Negar Kayedi Bakhtiari, Hooman Eshagh Harooni, Ahmad Ali Moazedi, Mohammad Mohammadi,
Volume 18, Issue 2 ( Summer 2014)
Abstract

Introduction: Previous studies have shown that zinc deficiency and castration could increase anxiety, while administration of zinc or testosterone has anxiolytic effects. This study examined the effect of zinc chloride administration on anxiety in gonadectomized male rats. Methods: For this purpose, adult male Wistar rats (weighing 200-250 g) were castrated. One month after surgery, different doses of zinc chloride (0, 5, 7.5 and 10 mg/kg IP) were administered 30 min before the elevated plus maze test. Time spent and the number of entries in open arms was recorded as measures of anxiety and the number of closed arm entries recorded as locomotor activity. Results: 1) Zinc chloride significantly decreased the time spent and the number of entries in the open arms in gonadectomized rats compared to the control group. 2) Zinc chloride administration could not decrease anxiety, even in the testosterone pretreated gonadectomized male rats. Conclusion: Our findings showed that zinc significantly increased anxiety in gonadectomized rats. Since our previous findings showed that zinc chloride decreased the anxiety level in intact male rats, it seems that zinc chloride effects on anxiety would change in relation to the presence or absence of the gonads and it might interact with androgenic system through an effect on the testis.
Zahra Moaiedfard, Hooman Eshagh Harooni, Ahmad Ali Moazedi, Gholam Ali Parham, Somaye Niknejad,
Volume 18, Issue 3 (Fall 2014)
Abstract

Introduction: Nitric oxide is an important messenger in hippocampal region which is affected in learning and memory processes and hippocampal responses to stress. In this study, we investigated the effect of L-NAME on passive avoidance memory in adult male rats exposed to restraint-stress. Methods: For this purpose, male Wistar rats were bilaterally implanted with cannulas aimed at the CA1 region of the hippocampus. Thirty min after intrahippocampl injections of saline (alone) or L-NAME (20, 40 and 80μg/0.5μl/side) animals were immobilized in restrainer for 2 h/day for 7 days (7 days after surgery), and then were tested for step-through latency and the time-spent in dark chamber in inhibitory avoidance task. Results: Our findings showed that intrahippocampal injection of L-NAME (80 μg/0.5 μl/side) significantly increased the step-through latency and decreased the time spent in the dark chamber in comparison with the control group. Conclusion: Since the inhibition of NO synthesis resulted in memory and learning improvements in rats exposed to restraint-stress, NO might be involved in stress related learning and memory deficits.

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