Evaluation of Cardiac Hemodynamic Parameters Following Ischemia-Reperfusion Injury in a Rat Model of Polycystic Ovary Syndrome

Introduction: Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women during reproductive ages. This syndrome is associated with disruption of sex hormone levels. Studies have shown that endurance of the heart to ischemia-reperfusion (I/R) injury can be affected by sex hormones. In the present study, the rate of cardiac tolerance against I/R injury in the PCOS rat model was compared with normal (control) rats. Materials and Methods: The rats were randomly divided into two groups; PCOS and control (n=8 per group). The hearts were isolated in Langendorff isolated heart system. Cardiac perfusion was performed in a retrograde flow in the aorta at constant pressure (75 mmHg) by Krebs-Henslit buffer. A pressure (5-10 mmHg) was put to the left ventricle, using an intraventricular balloon, to measure the hemodynamic parameters of the heart. Cardiac signals were recorded while being transmitted through the catheter to the Powerbull system. Results: Before I/R, the values for cardiac hemodynamic parameters including HR, LVDP, RPP and ± dp/dt, increased in the rat model of PCOS compared to controls, although these increases were not statistically significant (P>0.05). These parameters had decreasing trends after I/R in PCOS rats compared to controls which were not statistically significant (P>0.05). Conclusion: Cardiac resistance to I/R injury was found to be similar in both PCOS and control animals, which could be due to the cardioprotective role of sex hormones such as estrogens

Effects of Memantine, an NMDA Antagonist, on Metabolic Syndromes in Female NMRI Mice

Introduction: The brain glutamate neurotransmitter system and its NMDA receptors in the nucleus accumbens play an important role in the incidence of the phenomena of sensitivity and addiction. The present study examined the inhibitory effect of glutamate NMDA receptors in the nucleus accumbens in response to chronic stress. Methods: After the unilateral and bilateral cannula placement in the nucleus accumbens, one group of the animals received different intra-accumbens doses of memantine (0.1, 0.5 and 1 µg/mouse) 5 minutes before receiving the electric shock stress at their soles (using a Communication Box) and the other group received intraperitoneal doses of memantine (0.1, 0.5 and 1mg/kg) 30 minutes before receiving the same shock. Chronic stress increased the animals' plasma corticosterone, food and water intake and weight and reduced their defecation rates and eating latency.  Results: The intraperitoneal administration of memantine increased plasma corticosterone, water intake, fecal weight and eating latency, but had no effect on food intake or weight. The dose and site-dependent intra-accumbens administration of memantine either exacerbated the effects of stress on plasma corticosterone levels and water and food intake, or else had no effect on these parameters. Furthermore, the administration of memantine had no effect on animal’s weight and inhibited the effects of stress on fecal weight and eating latency. Discussion: The inhibition of glutamate NMDA receptors in the nucleus accumbens can inhibit and/or exacerbate the dose and site-dependent effects of chronic stress, with gender playing a significant role in producing this effect

The Effect of Intermittent Feeding on Metabolic Signs of Chronic Stress in Male NMRI Mice

Background and Objectives: Reduction of calorie (energy) intake can lead to stress management and improvement of nervous system function. In this research, the effect of intermittent feeding on metabolic signs of stress was investigated. Methods: Male laboratory mice with mean weight of 27&plusmn;3g were divided into 4 groups of 7 each. The control group received ad-lib food and water and did not have stress. The second group (experimental) was deprived from food 2 hours per day for one week, and then went under stress for 4 days. The third group was only deprived from food 2 hours per day for a week, and the fourth group received electric shock for 4 days without food deprivation. In this investigation, plasma corticosterone level, the amount of food consumption, delay in eating, weight gain, and the amount of feces, were measured. Data were analyzed using one-way ANOVA and Tukey test. The significance level was considered p<0.5. Results: In this study, stress increased the plasma level of corticosterone and fecal materials, and reduced food intake and weight of the animals and increased delay in eating. In the stress with intermittent feeding group, plasma level of corticosterone and delay in eating increased, and food intake and feces decreased. In this group, weight change was not observed, but in animals that only had intermittent feeding, increase in weight and food intake was observed. Also, delay in eating was decreased. Conclusion: The results of this study indicated that intermittent feeding can influence the effect of stress on nutrition and metabolism