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Background & Objective: In this research, we study the simultaneous effects of Nitric Oxide (NO) and stress on prefrontal cortex of rats. Nitric Oxide is an unstable small molecule that involved in many physiological and pathological conditions. Brain’s prefrontal cortex has important role on personality and mental state. Its development continues after birth and this period is the most sensitive time for brain’s cortex to response to environmental parameters such as psychological stresses. Materials & Methods: In this study Wistar male rats received L-arginine (200 mg/kg) as NO precursor, L-NAME (20mg/kg) and 7-nitroindazole (25mg/kg) as non specific and specific NO sentries inhibitors. L-arginine and L-NAME were injected intra peritoneal (IP) and 7-nitroindazole injected subcutaneously (S.C) during one month per day. Rats divided in two groups (with stress and without stress). The kind of stress was immobilization every day for one month during injection of materials. Brains were removed after this period and each brain with a coronal section manner divided in two parts .Anterior part of brain fixed by formalin and tissue processing was done. By using rotatory microtome 10? serial cross sections were obtained and stained with H & E. Posterior part of brain homogenized with such solution then amount of NO in obtained solution was measured by spectrophotometer with 540 nm wavelength. Results: Statistical analysis of light microscopic findings indicated that stress of immobilization with use of L-NAME and 7-nitroindazole result in decrease of thickness of prefrontal cortex , numbers of Betz cells and NO production in rats’ brain, it means L-NAME and 7-nitroindazole exaggerate the brain damage and from other hands L-arginine with stress can convert these results. Conclusion: On the basis of these results we believe that stress of immobilization damages prefrontal cortex and also NOS inhibitors can aggravate the cortical damage. On the other hand although NO precursor (L-arginine) decreases the cortical damage in rats that impress with stress, it can result in these changes in rat’s brain without stress.

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Background and Objective: Immobilization stress has a variety of effects on the enzymes activity. This study was conducted to determine the protective effect of Aloe vera extract on the serum level of creatine kinase enzyme in male rates exposed to acute and chronic immobilization stress. Materials and Methods: This experimental study was conducted on 45 male Wistar rats weighing approximately 200±30g. Animals were randomly allocated into 9 groups of 5 rats: control, normal saline, chronically immobilized, acutely immobilized, chronically immobilized normal saline, acutely immobilized normal saline, Aloe vera extract (600mg/kg/daily), acutely immobilized Aloe vera (600g/kg/daily) and chronically immobilized Aloe vera groups (600g/kg/daily). Aloe vera extract with a dose of 600mg/kg/BW was administered by gavage feeding before applying stress. For chronic immobilization, animals were put under immobilization stress for 2 hrs a day for 3 weeks and for acute immobilization animals were put under immobilization for 8hrs a day for one week. At the end of the experiments, blood samples were collected using cardiac puncture method and serum level of creatine kinase enzyme (units/L) was measured by spectrophotometery. Data were analyzed using SPSS-19, one-way ANOVA and Tukey post-hoc tests. Results: Serum level of creatine kinase enzyme represented a statistical significant increase in rats exposed to acute (2368.20±104.96 units/L) and chronic immobilization (2177.80±234.75 units/L) compared with control group (1240.40±706.40 units/L) (P<0.001). The enzyme alteration level was not significant in Aloe vera (1619.80±171.41 units/L), acutely immobilized Aloe vera extract (1619.00±206.03 units/L) and chronically immobilized Aloe vera extract (1448.00±106.07 units/L). Conclusion: This study showed that gavage of Aloe vera extract (600mg/kg/daily) in rats can prevent the elevation of creatine kinase enzyme activity resulted by immobilization stress.

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Background and Objective: Hydroalcholic extract of Peppermint is traditionally used for gastrointestinal disorders. This study was done to evaluate the effect of Peppermint extract on the mice colon motor activity following immobilization stress.

Methods: In this experimental study, 30 male Albino mice were randomly allocated into the three groups; including control, stress and stress + Peppermint oil groups (n=10). The second group as a stress group exposed to immobilization stress for four hours during three days. Third group as stress plus Peppermint oil group was exposed to stress in addition to administration of 27 mg/kg/bw Peppermint oil intraperitoneally prior to stress. After three days, intestinal and peristaltic activity was recorded using pressure transducer from in vitro segments of colon (4-5 cm in length. Also, fecal weight, food intake and body weight was measured for each mouse for in vivo condition.

Results: The mean±SD of fecal weight after three times stress immobilization was 1.36±0.71, 1.06±0.6 and 0.47±0.39 gr in control, stress and Stress + Peppermint oil groups, respectively (P<0.05). The mean±SD of internal luminal pressure after three times stress immobilization was 4.47±1.15, 3.48±1.25 and 0.77±0.37 mm/hg in control, Stress and stress + Peppermint oil groups, respectively (P<0.05).

Conclusion: Peppermint oil is a strong inhibitor for colon motor activity following immobilization stress.

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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.