en Cellular and molecular Neuroscience Cellular and molecular Neuroscience Original Original <p><strong>Introduction:</strong> The role of ovarian hormones and nitric oxide (NO) on oxidative damage in brain tissues as well as learning and memory has been widely investigated.</p><p>The present study was carried out to evaluate the effect of the precursor of NO, L-Arginine on learning and brain damage due to oxidative stress in ovariectomized (OVX) rats.</p><p><strong>Methods:</strong> Thirty -two rats were divided into four groups: 1) Sham, 2) OVX, 3) Sham-L-Arginine (Sham-LA) and 4) OVX-L-Arginine(OVX-LA).  The animals of sham- LA and OVX-LA were treated with 500 mg/kg of L-Arginine. The animals in Sham and OVX groups received 1 ml/kg saline. The animals were tested in Morris water maze and .nally, the brains were removed and MDA and total thiol concentrations were measured.</p><p><strong>Results:</strong> The escape latency and swimming path in OVX group were signi.cantly higher than in Sham group (p<0.01). The animals in OVX-LA group had signi.cantly lower swimming path length and escape latency compared to OVX group (p<0.01) while, there was no signi.cant difference between Sham- LA and Sham groups. In OVX-LA group, the brain tissues total thiol concentration was signi.cantly higher, and MDA concentration was lower than of OVX group (p<0.001).There was no signi.cant difference between Sham-LA and Sham groups. </p><p><strong>Discussion:</strong> It seems that the bene.cial properties of L-Arginine on spatial learning of ovariectomized rats are in part due to its protective capacity against oxidative damage.</p> Learning, Ovariectomy, L-Arginine, Morris Water Maze, Rat, Oxidative Stress. 36 44 http://bcn.iums.ac.ir/browse.php?a_code=A-10-1-129&slc_lang=en&sid=1 Mahmoud Hosseini 1370031947532846002253 1370031947532846002253 Yes Masoume Pourganji 1370031947532846002254 1370031947532846002254 No Fatimeh Khodabandehloo 1370031947532846002255 1370031947532846002255 No Mohammad Soukhtanloo 1370031947532846002256 1370031947532846002256 No Hoda Zabihi 1370031947532846002257 1370031947532846002257 No