In addition to its known classical roles, the renin angiotensin system (RAS) has more subtle functions which include the regulation of emotional responses. Previous studies regarding the anxiety related behavior of RAS have showed controversial results. There is also evidence that oxidative stress accompanies angiotensin II infusion, but the role of AT1/AT2 specific receptors is not clear. The aim of this study was to evaluate the effects of central angiotensin II receptor blockers on anxiety state and oxidative stress. Behavioral testing included elevated plus maze, while oxidative stress status was measured though the extent of a lipid peroxidation product (malondialdehyde-MDA) and the specific activity of some defense antioxidant enzymes (superoxide dismutase-SOD and glutathione peroxidase-GPx). The rats treated with angiotensin II spent significantly less time in the open-arms of elevated-plus-maze, while the administration of losartan resulted in a significant increase of this time. We observed a significant increase of MDA concentration in the angiotensin II group and a decrease of MDA levels in both losartan and PD-123177 groups. In addition, a significant correlation was seen between the time spent in the open arms and oxidative stress markers. These findings could lead to important therapeutic aspects regarding the use of angiotensin II receptor blockers in anxiety-related disorders.
 Ciobica A, Bild W, Hritcu L, Haulica I. Brain reninangiotensin system in cognitive function: preclinical findings and implications for prevention and treatment of dementia. Acta Neurol Belg. 2009;109: 171–180
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