Our previous study has shown that nanoparticles of magnesium oxide can cause memory corruption resulting from improved model of postpartum depression. Due to the effects of oxidative stress in the body nanoparticles in this study as an antioxidant role of vitamin C in the above model of depression And memory corruption caused by this model And its effect on memory improvement of acute and chronic nano magnesium oxide injection has been.
in this study, adult female mice (27±3) In 8 groups, including controls, depressed, depressed recipient of vitamin C in doses of 5 and 25 mg / kg As acute and chronic
and depressed nano-magnesium oxide in amounts of 1 and 5 mg / kg were divided into acute and chronic.Chronic administration of progesterone to induce postpartum depression were used and three days after cessation of administration Depression was assessed by testing the behavior of suspending tail Assess and immediately stop training and 24 hours after application of passive avoidance learning, memory, measured using the Step-down. Motor activity was evaluated by the open field.
Depression induced by progesterone led to a significant reduction in memory model mice (p˂0.05), respectively. vitamin C in doses of 5 and 25 mg / kg acute and chronic antidepressant effect (p˂0.001) show but only 5 mg acute and chronic improve the memory of mice (p˂0.001) was and decreased motor activity in chronic administration (p˂0.01). acute administration of magnesium oxide nanoparticles in quantities of 1 and 5 mg / kg showed no effect on depression while dependent on the amount without changing locomotor activity was significantly improved memory impairment due to depression (p˂0.01). chronic administration of the nanoparticle leads to a significant reduction in depression without improving memory. antidepressant effects of acute administration of vitamin C 5 mg of magnesium oxide nano-oxide 1 mg showed no difference with the Nano 1 mg but fell improve memory while in Chronic treatment showed more improvement and by increasing both the obvious effect of improving memory element dropped.
Vitamin C and magnesium oxide nanoparticles can improve depression and memory impairment caused it , But the amount of time using each of them, alone or together should be considered as a crucial factor.
 

Alzheimer's disease is a progressive brain disease that typically occurs in old age. Alzheimer's disease destroys neurons in cell structure that affects memory and behavior.
Aim of this study is the investigation the effects of acute and chronic administration of MgO nanoparticles, with the evaluation of magnesium ion concentrations, total antioxidant serum and histopathological changes of the rat hippocampuss in the Alzheimer-like model induced by streptozotocin (STZ)were investigated.
Regarding this, adult male Wistar rats divided into groups control, sham and treatment with two doses of the nano-magnesium oxide. To induce Alzheimer's disease, all mice except control group, received STZ (3 mg/5 µl of saline) into the lateral ventricles during anesthesia (with ketamine/xylazine). One week after surgery, passive avoidance learning was started by shuttle box device and saline or MgO nanoparticles (1 and 5 mg per kg) acutely and chronically were administered after training. Memory tests were done at 90 minutes or 24 hours after training and a week after chronic administration. Immediately after the test, blood was taken from the heart to evaluate serum magnesium levels, total antioxidant capacity and the brain hippocampus tissue was removed for histopathological evaluation.
The results showed that the injection of STZ significantly impairs memory up to a week after the training. Acute and chronic administration of MgO nanoparticles 1 mg/ kg rather than 5 mg/kg significantly improved short and long-term memory in the Alzheimer's mice (P<0. 01 and P< 0. 001).
Serum magnesium levels decreased in the Alzheimer's mice and MgO nanoparticles increased serum magnesium levels in the dose-dependent manner. Serum total antioxidant capacity showed a significant increase in presence of 1mg MgO nanoparticles rather than 5 mg .
Histopathologic results showed that magnesium oxide nanoparticles were capable of improving streptozotocin-induced cell lesions in different parts of the hippocampus.
Due to all the above results, it seems that MgO nanoparticles have the potential to improve brain lesions that have led to loss of memory and can be considered as an important drug candidate for Alzheimer's disease.
 

Previous studies have shown that plasma magnesium level in postpartum depression in mothers is reduced and this reduction could lead to memory impairment. Since it is known that magnesium oxide nanoparticles can contribute to learning and memory, and so far no studies have been performed on the effects of magnesium oxide nanoparticles on memory impairment in postpartum depression. Therefore, aim of this study was the evaluation of magnesium oxide nanoparticles effects on passive avoidance memory in the model of postpartum depression. In this study, 82 NMRI adult female mice in the weight range of 27 to 30 g divided into 12 groups of control, vehicle, progesterone and depressed groups that received magnesium oxide nanoparticles in doses of 1, 2.5, 5 and 10 m g / kg with acute and chronic administration. All injections were administered intraperitoneally. To induced postpartum depression, the mice received progesterone for 5 consecutive days that had been prepared in sesame oil solvent. After stopping for 3 days, on the eighth day, depression was evaluated by measuring the duration of immobility times in the tail suspension test in 6 minutes. The Step-down apparatus was used to evaluate the passive avoidance memory. In acute administration , 30 minutes after intraperitoneal injection of nanoparticles, animal training and 24 hours later, the memory test were taken from each mice separately. Duration of times that mouse was stay on the platform taken as a index to measure of memory. In chronic administration, after 7 consecutive day received magnesium oxide nanoparticles, tests were performed on the eighth day. Locomotor activity of all groups was measured by the open field test after evaluated memory. Results showed that induction of postpartum depression caused a significant increase in the duration of immobility times and a significant reduction in the memory of mice and found that acute administration of magnesium oxide nanoparticle caused significant dose-dependent improvement in memory impairment due to depression without changes in locomotor activity, while the chronic administration of this nanoparticle was lead to relative improvement of memory. It seems that magnesium oxide nanoparticles by cross the blood-brain barrier affect the processes of memory formation by interfering with neurochemical systems involved in depression, has prevented memory impairment caused by its. Probably the amount and duration of administration of the nanoparticle can be a determining factor.

In this research the effects of magnesium oxide nanoparticles (MgO NP) on anxiety induced by reduction of opioid system activity and the mediatory role’s of endogenous opioids and also the effect of the nano-oxide on anxiety and signs induced morphine withdrawal were investigated. For this purpose, 91 adult male NMRI mice weighing 27 ± 5 g divided into 15 groups of 6 animals: control group (saline), groups receiving MgO NP (1, 2/5, 5mg / kg), naloxone (3, 5mg/ kg) and pre and post administration of MgO NP (2.5mg/kg)+naloxone (5mg/kg), addicted groups receiving saline or MgO NP (2/5, 5 &10 mg/kg) as acute and chronic administration. All addicted groups, chronic morphine received through 1th, 2th, 3th day dose 20, 40, 80 mg/kg of morphine three times at 8 am, 1 pm and 6 pm and fourth day a dose 40 mg/kg morphine. 3 hours after the last injection of morphine to induce withdrawal syndrome, naloxone 5 mg/kg was injected intraperitoneally. In all groups, after naloxone injection, the signs of morphine withdrawal such as jumping, climbing, standing on two legs, and weighting loss were evaluated. Then anxiety behavior was assessed using the elevated plus maze. All of injections was intraperitoneally except for morphine that was conducted as subcutaneously. The results showed that:
MgO NP reduced anxiety behavior with increasing OAT% (P<0/05) and OAE% (P <0.05 and P <0.01) in dependent manner without changing the locomotor activity. Naloxone increased anxiety behavior by reducing OAT% and OAE% (P <0/05) without affecting motor activity, in a dose-dependent manner. MgO NP
reduced anxiogenic effect of naloxone and this drug could not completely inhibit the anxiolytic effect of MgO NP.
MgO NP in acute and chronic administration attenuated anxiety induced by morphine withdrawal and chronic injection was much stronger than the acute form. Meanwhile MgO NP could improve the signs of morphine withdrawal, especially standing on two feet, climbing and weight loss. According to the results, it seems that MgO NP can be considered as a candidate for the treatment of anexiety induced by morphine addiction.
 

<p style="text-align: left;">This study is designed to clarify the effects of acute and chronic administration of nano zinc oxide (ZnO) and conventional form on passive avoidance memory and their effects on hippocampal tissue of brain in mice.<br /> In this study, NMRI adult male mice weighing 25 &plusmn; 5 g in groups of control, recipent of different doses of nano and conventional ZnO (1, 2.5, 5 mg/kg IP) as an acute injection before and after training and receiving groups of chronic administration of these components (1, 5 mg/kg IP) pre-training on passive avoidance memory test were used. For evaluation passive avoidance memory a step down device was used. Memory retrieval were evaluated in an acute injection groups at 1, 3 and 7 day post of training while in chronic injection groups 1 day post training of passive avoidance task and their brains were removed for histological evaluation.<br /> The results showed that nano and conventional ZnO in doses of 2.5 and 5 mg/kg pre- training induces significant impairment of memory, while the post-training injections of 5 mg/kg nano ZnO improved memory retrieval. ژhronic administration of both ZnO had no effect on passive avoidance memory while in the histologically, nano ZnO in dose of 1 mg/kg resulted in necrosis of cells in different regions of the hippocampus. Both of ZnO in dose of 5 mg/kg created less damaging effect on hippocampal tissue.<br /> With the results obtained, it seems acute administration of ZnO in two scales have different effect on acquisition and retrieval phases and improvement and weaken of these compounds is time dependent of injection. In chronic injection, the number of necrotic cells in hyppocampus was not sufficient for learning and memory dysfunction.<br /> &nbsp;</p>

 Previous studies have shown that magnesium oxide nanoparticles improve passive avoidance memory in adult mice. According to the cholinergic system is important for memory formation and so far the studies don’t have been done on the relationship between this system and magnesium, so this study was designed to examine the effect of magnesium oxide nanoparticles in the presence of memory impairment induced by atropine (muscarinic receptors antagonist) on passive avoidance memory.In this study of 182 adult male mice were used. The animals randomly divided into 7 groups, including control and received different doses of nano magnesium oxide (1, 2.5 & 5 mg/kg) and atropine (0.1 and 1 mg/kg), respectively. These drugs are administered intraperitoneally before and after training and before testing memory. The index of memory was measured after training as latency time coming down of the safe platform of step-down device in the 1, 3 and 7 days. To investigate the association between magnesium oxide and cholinergic system, atropine was used to block cholinergic receptors and performance of magnesium oxide nanoparticles were then measured in the presence of it. Locomotor activity were measured in all groups after memory evaluation. The results showed that nano magnesium oxide in doses of 2/5 and 5 mg/kg after training improves passive avoidance memory without any changes in locomotor activity. Atropine administration after training in dose of 0.1 mg was ineffective but in dose of 1 mg/kg induced considerably amnesia. The improvement effect of nano magnesium oxide in the presence of atropine 0.1 mg/kg was inhibited up to a week. Nano magnesium oxide (5mg/kg) reversed memory impairment induced by atropine 1 mg/kg without any changes in locomotor activity. It seems that there is a interaction between the cholinergic system and nano magnesium oxide, probably the potentiating effect of magnesium oxide nano particles on memory due in part to the cholinergic system.