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Öğe 3?,4?-Dihydroxyflavonol attenuates spatial learning and memory impairments in global cerebral ischemia(Taylor & Francis Ltd, 2017) Oz, Mehmet; Demir, Enver Ahmet; Caliskan, Merve; Mogulkoc, Rasim; Baltaci, Abdulkerim Kasim; Atalik, K. Esra NurullahogluObjectives: In the present study, effects of 3', 4'-dihydroxyflavonol (DiOHF) on anxiety-like behavior, and learning and memory were investigated in a model of transient global cerebral ischemia and reperfusion. Methods: The animals were assigned to sham-operated, ischemia, and two DiOHF-treated (10 mg/kg i. p.) groups. DiOHF was administered at 1 hour before and immediately after the ischemia. Male rats were subjected to bilateral common carotid artery occlusion to induce acute cerebral ischemia for 20 minutes, followed by reperfusion for 7 days. The openfield, elevated plus maze (EPM), and Morris water maze tests were used to evaluate the effects of DiOHF treatment on ischemia-induced locomotor activity, anxiety-like behavior, and spatial and recognition memory impairments, respectively. Results: In the open field test, locomotor activity in the ischemic rats was not altered 6 days after the ischemia, nor was anxiety-like behavior, which was evaluated with the EPM (P > 0.05). In the water-maze test, cerebral ischemia significantly decreased the exploration time in the target quadrant, and the platform crossing counts were lower (P < 0.05) in the probe trial test; this memory impairment was significantly improved by DiOHF applied 1 hour before and immediately after ischemia (P < 0.05). Discussion: All together, these findings suggest that DiOHF reverses spatial learning and memory deficits resulting from transient global ischemia but has no significant effect on anxiety-like behavior.Öğe Curcumin alleviates cisplatin-induced learning and memory impairments(Academic Press Inc Elsevier Science, 2015) Oz, Mehmet; Atalik, K. Esra Nurullahoglu; Yerlikaya, F. Humeyra; Demir, Enver AhmetThe present study has been designed to investigate the role of curcumin on cisplatin-inducedcognitive impairment and to reveal mechanisms of cisplatin's detrimental actions on cognition in rats. Animals were treated with cisplatin (5 mg/kg/week) and/or curcumin (300 mg/kg/day) for 5 weeks. Morris water maze test was used to assess spatial learning and memory. Enzymatic activities of acetylcholinesterase (AChE) and superoxide dismutase (SOD) were evaluated from hippocampus and plasma samples, and malondialdehyde (MDA), which is the end-product of lipid peroxidation, was determined by a colorimetric method. Our results showed that cisplatin (5 mg/kg/week, 5 weeks) caused learning and memory deficits, elevated MDA content, decreased SOD activity in the hippocampus and plasma, and AChE activity in the hippocampus. Curcumin improved learning and memory in rats with administration of cisplatin. In addition, curcumin significantly reduced the level of MDA and increased the activities of SOD and AChE. Taken together, our findings indicate that curcumin ameliorates cisplatin-induced spatial learning and memory impairment, possibly through restored cholinergic function and enhanced oxidative status. (C) 2015 Elsevier Inc. All rights reserved.Öğe Effects of Cisplatin and Curcumin on the Hypothalamic-Pituitary-Adrenal Axis(Wiley-Blackwell, 2015) Oz, Mehmet; Demir, Enver Ahmet; Gergerlioglu, Hasan Serdar; Atalik, Kismet Esra Nurullahoglu; Yerlikaya, Fatma Humeyra[Abstract Not Availabe]Öğe Effects of the Environmental Enrichment on Learning and Memory in High-Fat Diet-Fed Rats(Wiley-Blackwell, 2015) Oz, Mehmet; Demir, Enver Ahmet; Gergerlioglu, Hasan Serdar; Atalik, Kismet Esra Nurullahoglu; Yerlikaya, Fatma Humeyra[Abstract Not Availabe]Öğe Environmental enrichment reverses cognitive impairments provoked by Western diet in rats: Role of corticosteroid receptors(Pergamon-Elsevier Science Ltd, 2016) Gergerlioglu, Hasan Serdar; Oz, Mehmet; Demir, Enver Ahmet; Nurullahoglu-Atalik, Kismet Esra; Yerlikaya, Fatma HumeyraAims: Previous studies demonstrated that the Western diet (WD), which is rich in saturated fat (HFD) and refined sugar (HSU), is related to the impairments of hippocampus-dependent learning and memory and forebrain synaptic plasticity in rodents. The environmental enrichment (EE) has been shown to enhance learning and memory in theHFD-induced cognitive deficits, but the exact mechanismis still not clearly understood. Therefore, the present study aimed to clarify the effects of the EE on spatial memory in WD-fed rats, and to analyze the potential role of corticosteroid receptors in the EE conditioning. Main methods: MaleWistar albino rats were housed in either an enriched or standard environment and fed with the HFD (35% of energy as fat), HSU (100% of carbohydrate as sucrose) or standard rat chowfor 4 weeks. Weused the Morris' water maze test (MWM) to assess the learning and memory performance, and measured plasma levels of corticosterone (CORT) and adrenocorticotropic hormone (ACTH), as well as glucocorticoid (GR) and mineralocorticoid receptor (MR) levels in the hippocampus. Key findings: The results showed that HFD-fed rats displayed poorer learning and memory performance evaluated with MWM than controls. The EE reversed the cognitive deficits caused by the HFD. In addition, the EE resulted in an increase of GR and MR levels without affecting plasma CORT and ACTH concentrations. Significance: Based on these findings, it could be suggested that the EE plays an important role in amelioration of the HFD-induced cognitive impairments, but this intervention is independent of the hypothalamic-pituitaryadrenal axis and hippocampal corticosteroid receptor levels. (C) 2016 Elsevier Inc. All rights reserved.Öğe Hipotalamik-hipofizer-adrenal aks üzerine sisplatin ve kurkuminin etkileri(2017) Öz, Mehmet; Demir, Enver Ahmet; Gergerlioğlu, Hasan Serdar; Nurullahoğlu Atalık, Kısmet Esra; Yerlikaya, Fatma HümeyraAmaç: Son yıllarda zerdeçaldaki aktif polifenol olan kurkumininsisplatin içeren kemoterapi rejimlerinde sinerjistik bir role sahip olduğunu gösteren bilgiler artmaktadır. Kurkuminin güvenli bir adjuvan olduğunu göstermek için söz konusu ajanların sistemik etkileşimlerinin araştırılması gerektiğinden bu polifenolünsisplatin uygulanan sıçanlarda hipotalamik-hipofizer-adrenal (HPA) aksa etkilerinin incelemesi amaçlandı.Gereç ve Yöntem: Toplamda 34 erkek Wistar sıçan kontrol (n7), sisplatin (n10), kurkumin(n7) ve sisplatin kurkumin (n10) olmak üzere dört gruba ayrıldı. Sisplatin ve kurkumin gruplarındaki sıçanlara 5 hafta süresince (sırasıyla) 5 mg/kg/hafta, i.p. sisplatin ve 300 mg/kg/gün, p.o. kurkumin uygulandı. Sisplatin kurkumin grubu aynı dozlarda hem sisplatin hem kurkumin aldı. Kontrol grubuna yalnızca taşıyıcı (fizyolojik salin ve mısır yağı) verildi. Hayvanlar adrenokortikotropik hormon (ACTH) ve kortikosteron (CORT) ölçümleri için kan elde etmek maksadıyla eksanguine edildi. Beyin çıkarıldı ve hipokampal dokuda mineralokortikoid (MR) ve glukokortikoid (GR) reseptörleri belirlendi. Analizler ELISA yöntemiyle gerçekleştirildi.Bulgular: Sisplatin ve kurkumin tedavilerinin araştırılan parametreleri bozmadığını bulduk (p0.05). Ayrıca, kurkumin ve sisplatinin birlikte uygulanmasının kontrollere kıyasla ACTH ve CORT'un plazma konsantrasyonları ile hipokampal MR ve GR seviyelerini değiştirmediğini gözlendi (p0.05).Sonuç: Sonuçlarımıza göre tek başına veya kombine halde sisplatin ve kurkumin tedavisi HPA aksını etkilememektedir.Öğe Impact of enriched environment on production of tau, amyloid precursor protein and, amyloid-? peptide in high-fat and high-sucrose-fed rats(Cambridge Univ Press, 2017) Selvi, Yavuz; Gergerlioglu, Hasan Serdar; Akbaba, Nursel; Oz, Mehmet; Kandeger, Ali; Demir, Enver Ahmet; Yerlikaya, Fatma HumeyraObjective: The Western-type diet is associated with an elevated risk of Alzheimer's disease and other milder forms of cognitive impairment. The aim of the present study was to investigate the effects of the environmental enrichment on amyloid and tau pathology in high-fat and high-sucrose-fed rats. Methods: In total, 40 adult male rats were categorised into two main groups according to their housing conditions: enriched environment (EE, n = 16) and standard housing condition (n = 24). The groups were further divided into five subgroups that received standard diet, high-fat diet, and high-sucrose diet. We performed the analysis of amyloid beta-peptide (A beta) (1-40), A beta(1-42), amyloid precursor protein (APP), and tau levels in the hippocampus of rats that were maintained under standard housing conditions or exposed to an EE. Results: The EE decreased the A beta(1-40), A beta(1-42), APP, and tau levels in high-fat and high-sucrose-fed rats. Conclusion: This observation shows that EE may rescue diet-induced amyloid and tau pathology.
