[Effect of memantine administration within the nucleus accumbens on changes in weight and volume of the brain and adrenal gland during chronic stress in female mice]

In the present study, we examined the effects of memantine administration within the nucleus accumbens on the alterations in brain and adrenal volumes and weight ratios induced by stress from electric foot shock. A group of mice received various doses of memantine [0.1, 0.5 and 1 mg/kg] prior to induction of stress. Another group underwent intra-accumbal cannulation after anesthesia. One week later, memantine [0.1, 0.5 and 1 micro g/mouse] was injected within the nucleus accumbens prior to induction of stress. Subsequently all animals were killed. Their brains and adrenal glands were removed and fixed in 4% formalin. The volume and weight was determined by mercury immersion and method respectively. The stress group showed evidence of reduction in brain volume and weight ratio to volume, and weight of the adrenal gland. Memantine increased the ratio of the brain volume and weight to the volume and weight of the adrenal gland. Memantine administration within the nucleus accumbens also could alter this ratio. Hence, all three doses of memantine that were injected on the right side and bilateral to the nucleus inhibited the effects of stress. Inhibition of NMDA receptors in the nucleus accumbens can inhibit the destructive effects of chronic stress on brain volume and weight. In addition, memantine can inhibit the influence of stress on adrenal volume and weight. We have shown that this effect was both dose and injection site dependent. In this regard, the left side of the nucleus was weaker

[The effect of short and mid-term psychological stress on metabolic, hormonal and behavioral parameters in male rats]

Background and objective: Stress specially the chronic psychological one is an important issue of our modern society. In this regard, this study has been investigated the effects of chronic psychological stress on metabolic, hormonal and behavioral parameters.

Materials and methods: The present study is an experimental intervention.The animals were divided into control and stressed groups and then subdivided into 15 and 30 days [n=7]. Stress was induced by the communication box.This device consisted of 9 chambers. The animals received electrical shock in five chambers and the animals in four chambers exposed to various emotional. Chronic stress for 15 and 30 days [h / day1] was applied. Blood sampling was done by using retro orbital puncture method. The plasma levels of glucose, cholesterol, triglyceride, insulin, and corticosterone were measured. In addition, feed and water intake, latency to eat and drink, adrenal and body weights were determined. For statistical analysis a mixed analysis of variance with repeated measures within the stressed and control groups and independent measures between the two groups was performed by SPSS Version 16.0 program package. The level of significance was considered less than 0.05.

Results: Chronic psychological stress did not significantly change plasma corticosterone [P=0.41], insulin [P=0.45], glucose [P=0.47], triglyceride [P=0.07] and cholesterol [P=0.26] levels. 30 days chronic stress significantly increased feed intake compared to control ones [P=0.01]. Whereas water intake [P=0.07], latency to eat [P=0.70] and drink [P=0.08] did not change significantly in the stressed group. 30 days exposure to the stress in both control and stressed groups increased body [P=0.002 and P=0.004 respectively] and adrenal [P=0.01 and P=0.04 respectively] weights markedly compared to day 15.

Conclusion: short and mid-term psychological stress did not change hormonal and metabolic parameters significantly, whereas feed intake was significantly increased. However, no significant difference was observed in body weight of stressed animals compared to controls.

Oral morphine consumption reduces lens development in rat embryos

Consumption of morphine, during pregnancy, in addition to inducing defects in the mother's nervous system function, caused defects or delays in the formation and evolution of embryonic visual system. In the present study, changes in lens development were assessed in embryos exposed to morphine in utero. Female Wistar rats [250-300 g] were mated with male rats and pregnancy was determined by sperm observation in vaginal smear. This day was considered as embryonic day zero [E0]. The females were then divided randomly into the experimental and the control groups. The control group received tap water and the experimental group received morphine [0.05 mg/ml] in their water. On embryonic day 13 [E13], blood samples were collected from the retro-orbital sinus of all animals for plasma corticosterone detection. On embryonic day 17[E17], the animals were killed by an overdose of chloroform and the embryos were taken out surgically. The embryos were fixed in 10% formalin for 30 days. At this time, the head of the embryos were removed for tissue processing and Hematoxylin- Eosin [HandE] staining. The samples were evaluated using light microscope and MOTIC software. Our data indicated that plasma corticosterone level was dramatically increased and the lens was thinner in the experimental group. [Although the proliferation of lens cells increased in the experiment group but that lens had delay in removing the proliferated and elongation cells with abnormal density in the lateral part of the lens in comparison with the control group]. Moreover, the opening of the eyelids was delayed in the off springs of the mothers who received morphine. This study showed that morphine consumption during pregnancy leads to defects in fetal visual system development, particularly in the lens, and eyelids

Influence of nitric oxide in the central amygdala on the acquisition and expression of morphine-induced place preference in morphine sensitized rats

Effects of intra-central amygdala administration of L-arginine, a nitric oxide precursor, and NG-nitro-L-arginine methyl-ester [L NAME], a nitric oxide synthase inhibitor, on the morphine-induced sensitization and also on the expression of morphine-induced place conditioning in rats were studied. Subcutaneous [s.c.] administration of morphine [2.5, 5 and 7.5 mg/kg] induced place conditioning. Repeated pretreatment of morphine [5 mg/kg, i.p.] followed by 5 days no drug treatment, increased place conditioning induced by morphine [0.5 mg/kg]. Repeated intra-central amygdala administration of L-arginine [0.3, 1 and 3 µg/ rat], with morphine during acquisition of sensitization, significantly increased or reduced morphine place conditioning in sensitized rats. The drug administration before testing also increased and reduced the expression of morphine place conditioning in sensitized animals. Repeated intra-central amygdala injections of L-NAME [0.3, 1 and 3 µg/rat] with morphine during acquisition of sensitization, reduced the acquisition of morphine place conditioning in the sensitized animals. The drug injection before testing also reduced morphine induced conditioning. The results indicate that nitric oxide [NO] within the central amygdala may be involved in the acquisition and expression of morphine place conditioning in morphine-sensitized rats

Effects of oral morphine on the larvae, pupae and imago development in drosophila melanogaster

Previous studies, focusing on the effects of abused drugs, have used mice or rats as the main animal models; the present study tries to introduce a simple animal model. For this propose, we investigated the effects of oral morphine consumption by parents on the development of larvae, pupae and imago in Drosophila Melanogaster [D. Melanogaster]. In this experimental study, twenty male and 20 female D. Melanogaster pupae were housed in test tubes with banana [5 pupae /tube]. Male and female groups each were divided into three experimental group and one control group, which were maintained at 25 [degree sign] C. Morphine [0.2, 0.02, 0.002 mg/ml] was added into the test tubes of the experimental groups. The control group maintained at morphine-free test tube. The male and female groups with the same treatment were coupled and then female fertilization, egg deposit, larval, pupae and imago stages were studied macro and microscopically. The SPSS software [version 9.01] was used for statistical evaluations. In the experimental groups, in the larvae stage, both increase and decrease of length and surface area in the pupae stage were observed. The number of larvae pupae, and imago was reduced in the experimental groups. The study showed that oral morphine consumption by parents may affect the development of larvae, pupation and imago stages in D. Melanogaster. The results also showed that D. Melanogaster may be a reliable animal model to study on the concerns about abused drugs especially those with opioids