The effect of psychical stress on cause and exacerbation of diabetes mellitus, serum glucose and cortisol levels, and body weight in rats

زمینه و هدف: در تحقیق حاضر تأثیر استرس روانی مزمن بر تغییرات سطح سرمی گلوکز وکورتیزول و همچنین اختلاف وزن ابتدا و انتهای آزمایش و تأثیر آن در بروز و یا تشدید دیابت شیرین بررسی گردید. مواد و روشها: بدین منظور در طی یک سری آزمایشات این متغیرها در 7 گروه هشــت تایی (8n=) از رات نر نژاد Wistar با وزن ابتدایی (250-200 گرم) تحت سنجش قرار گرفتند. در این تجربه از استرس روانی ترس از خفگی در آب به مدت یک دقیقه در هر ساعت و چهار ساعت در هر روز در طی 14 روز استفاده گردید. نتایج: این تحقیق نشان داد که: 1) اگرچه این نوع استرس تکراری و مزمن باعث تغییر معنی داری حدود22 در سطح گلوکز سرم شد (01/0

The effect of preventive, therapeutic and protective exercises on hippocampal memory mediators in stressed rats

Background: Exercise plays a significant role in learning and memory. The present study focuses on the hippocampal corticosterone (CORT), interleukin-1 beta(IL-1β), glucose, and brain derived neurotrophic factor (BDNF) levels in preventive, therapeutic, and protective exercises in stressful conditions. Methods: Forty male rats were randomly divided into four groups: the control group and the preventive, therapeutic, and protective exercise groups. The treadmill running was applied at a speed of 20-21m/min and a chronic stress of 6 hours/day for 21 days. Subsequently, the variables were measured in the hippocampus. Results: The findings revealed that the hippocampal CORT levels in the preventive exercise group had a significant enhancement compared to the control group. In the protective and particularly the therapeutic exercise groups, the hippocampal CORT levels declined. Furthermore, the hippocampal BDNF levels in the preventive and the therapeutic exercise groups indicated significantly decreased and increased, respectively, in comparison with the control group. In the preventive exercise group, however, the hippocampal glucose level turned out to be substantially higher than that in the control group. Conclusion: It appears that the therapeutic exercise group had the best exercise protocols for improving the hippocampal memory mediators in the stress conditions. By contrast, the preventive exercise group could not improve these mediators that had been altered by stress. It is suggested that exercise time, compared to stress, can be considered as a crucial factor in the responsiveness of memory mediators. � Penerbit Universiti Sains Malaysia, 2016