کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2014132 | 1067145 | 2009 | 6 صفحه PDF | دانلود رایگان |

Effects of chronic stress are not completely understood. They may underlie depression and dementia. This study assessed the association between chronic stress, glutamate levels, tau-protein phosphorylation, and nitric-oxide in old rats exposed to chronic mild stress (CMS). Old (> 15 months) male Wistar rats were exposed to CMS. Comparison groups included old and young control rats, young CMS-exposed, and old CMS-exposed rats treated with the neuronal nitric-oxide synthase (nNOS) enzyme inhibitor, 7-nitroindazole (20 mg/kg/day i.p.). Hippocampal glutamate levels and glutamate decarboxylase (GAD) activity were determined and tau protein phosphorylation was assessed. Age was a significant (p = 0.025) source of variation in glutamate level [811.71 ± 218.1, 665.9 ± 124.9 µmol/g tissue protein (M ± SD) in young and old control rats, respectively]. Old rats exposed to CMS were characterized by an increased risk to develop anhedonia. There was significant (p = 0.035) decrease in GAD enzyme activity (− 60.06%) and increased tau protein hyperphosphorylation in old rats exposed to CMS compared to control. Administration of 7-nitroindazole to CMS-exposed old rats significantly (p = 0.002) increased GAD activity, decreased glutamate levels (7.19 ± 3.19 vs. 763.9 ± 91 µmol/g tissue protein; p = 0.0005), and decreased phosphorylation of tau proteins compared to CMS exposed rats.
Journal: Pharmacology Biochemistry and Behavior - Volume 91, Issue 3, January 2009, Pages 339–344