کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10306429 | 547170 | 2011 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Dim light at night provokes depression-like behaviors and reduces CA1 dendritic spine density in female hamsters
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
علوم غدد
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![عکس صفحه اول مقاله: Dim light at night provokes depression-like behaviors and reduces CA1 dendritic spine density in female hamsters Dim light at night provokes depression-like behaviors and reduces CA1 dendritic spine density in female hamsters](/preview/png/10306429.png)
چکیده انگلیسی
The prevalence of major depression has increased in recent decades; however, the underlying causes of this phenomenon remain unspecified. One environmental change that has coincided with elevated rates of depression is increased exposure to artificial light at night. Shift workers and others chronically exposed to light at night are at increased risk of mood disorders, suggesting that nighttime illumination may influence brain mechanisms mediating affect. We tested the hypothesis that exposure to dim light at night may impact affective responses and alter morphology of hippocampal neurons. Ovariectomized adult female Siberian hamsters (Phodopus sungorus) were housed for 8 weeks in either a light/dark cycle (LD) or a light/dim light cycle (DM), and then behavior was assayed. DM-hamsters displayed more depression-like responses in the forced swim and the sucrose anhedonia tests compared with LD-hamsters. Conversely, in the elevated plus maze DM-hamsters reduced anxiety-like behaviors. Brains from the same animals were processed using the Golgi-Cox method and hippocampal neurons within CA1, CA3, and the dentate gyrus were analyzed for morphological characteristics. In CA1, DM-hamsters significantly reduced dendritic spine density on both apical and basilar dendrites, an effect which was not mediated by baseline cortisol, as concentrations were equivalent between groups. These results demonstrate dim light at night is sufficient to reduce synaptic spine connections to CA1. Importantly, the present results suggest that night-time low level illumination, comparable to levels that are pervasive in North America and Europe, may contribute to the increasing prevalence of mood disorders.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Psychoneuroendocrinology - Volume 36, Issue 7, August 2011, Pages 1062-1069
Journal: Psychoneuroendocrinology - Volume 36, Issue 7, August 2011, Pages 1062-1069
نویسندگان
Tracy A. Bedrosian, Laura K. Fonken, James C. Walton, Abraham Haim, Randy J. Nelson,