Background: Progesterone is a female steroid hormone that has a potent anticonvulsant effect on human and animal. The aim of this study was to investigate the involvement of opioid receptors in the anticonvulsant effect of progesterone on ovariectomized mice.

Materials and Methods: In this experimental study, all animals were ovariectomized. After two weeks, they received an intraperitoneal (i.p.) injection of drugs (progesterone and naloxone) or saline. The animals also received a subcutaneous injection of strychnine for induction of convulsive seizures, 30 minutes after administration of drugs or saline. For evaluation of convulsion in the animals, convulsion onset time, convulsion duration, the number of seizures, and death time were recorded.

Results: Progesterone (25 and 50 mg/kg, i.p.) decreased the strychnine-induced convulsion. The anticonvulsant effect of 50 mg/kg of progesterone was abolished by naloxone (5 mg/kg, i.p.) injection, whereas administration of the same doses of naloxone alone did not affect strychnine-induced convulsion.

Conclusion: These results suggest that opioid receptors may play an important role in the anticonvulsant effect of progesterone.

Background: Studies have shown that central cholinergic system can be effective on animal memory in objects emplacement, but there were no sufficient information about the consumption of effective substances on this system during pregnancy in novel object recognition in compared to old object and its effect on the fetus. The aim of this study is investigation of lecithin (as a source of choline) effect during pregnancy and lactation on object recognition behavior as a marker of cognitive memory in male and female rat offspring.

Materials and Methods: In the present experimental study, female rats with an average weight of 160±10 g were gavaged of pregnancy (22 days) until 21 days after the parturition by different amounts of lecithin or its vehicle. The groups were: control (without receiving any medications), vehicle and receiving lecithin with amounts 120 and 240 mg/kg. After gender segregation, at 36 days of birth offspring were trained to evaluate the recognition memory. The number of offspring in each group for each sex was 7.

Results: Results showed that consumption of lecithin 240mg/kg in female offspring was lead to increase in percentage of time spent in near of novel object in compared with vehicle group (p<0.05). While in other groups there was no difference between offspring.

Conclusion: Lecithin consumption during mother pregnancy and lactating lead to change in precognitive memory of female offspring and also sex can cause different effects of this compound in the body of an animal.

Background: With the increasing use of nanoparticles of zinc Oxide (nZnO) in the industry, the pharmaceutical and chemical industry, the effects of the nanoparticles on opioid dependence and its possible interaction with vitamin C (as an antioxidant agent) has not been indicated. This study aimed to clarify the effect of ZnO nanoparticles on morphine dependence in the presence and absence of vitamin C in CPP method.

Materials and Methods: In this study, adult male mice weighing 25±3 g were used in the groups which received different doses of morphine(2/5, 5, 10 mg/kg, Sc), Nano ZnO (1, 2.5, 5, 10 mg/kg, IP), vitamin C (1, 5, 25 mg/kg, IP) and groups which receiving combination of vitamin C and nano ZnO. All categories received morphine 5 mg / kg, for induction and diagnosis of dependence in CPP.

Results: Nano ZnO concentrations (2.5, 5, 10 mg/kg, IP) caused a significant decrease in morphine CPP (p <0.01, p <0.001) and the 1 mg/kg of nano was ineffective. Vitamin C in doses of 5 and 25 mg/kg decreased the expression of morphine-induced conditioned place preference (p<0.01) and a value of 1 mg/kg had no effects. All doses of ZnO in the presence of ineffective dose of vitamin C showed a stronger inhibitory effect than to alone nZnO in morphine CCP.

Conclusion: The combination of vitamin C and Nano ZnO are more effective to deal with the psychological dependence to morphin and probably can provide a new approach to addiction treatment.

  Background: Failure to pass the blood-brain barrier is a serious challenge to the use of magnesium in the treatment of neurologic disorders. But , recently, applying magnesium oxide nanoparticles that is capable of crossing biological barriers has created new hopes. According to the reinforcing effects of magnesium oxide nanoparticles on memory and ambiguity in the best time of application and duration of its effects, the aim of the present study was to compare effects of pre-and post-training administration of different doses of magnesium oxide nanoparticles on long-term memory.

  Materials and Methods: In this experimental study, fifty- six adult male NMRI mice in the control group and receiving magnesium oxide nanoparticles group at doses of 1, 2.5 and 5 mg/kg (I.P) before and after training were used. Long-term memory of mice in a week on days 1,3and7 days after training (shock) by using step-down device and passive avoidance learning method was assessed. Time latency in coming down the secure platform was considered as the memory assessment scale.

  Results: The results showed that injection of nano-magnesium oxide in both the 2.5 and 5 mg/kg improved memory through increasing the latency in coming down the secure platform during a week (p< 0.001), without any changes in locomotor activity, whereas, it had no effect at 1 mg dose. Pre-training injection of magnesium oxide nanoparticles increased memory relatively, it wasn't statistically significant compared to the control group.

  Conclusion: According to the above results, magnesium oxide nanoprticles improves long term memory, and it is possible when the training and the acquisition has occurred, otherwise it will not make a significant impact .