Biomedical subjects

Gulay Hacioglu

Publications and source records attributed to Gulay Hacioglu.

5 recordsLinked to original sources

PubMed2006

Beneficial effects of docosahexaenoic acid on active avoidance performance in 1K-1C hypertensive rats.

The present study evaluated the role of chronic docosahexaenoic acid (DHA) supplementation on active avoidance learning task performance in experimental hypertension. Male Wistar rats were randomly divided into five experimental groups as follows: control, sham, DHA treated, 1K-1C hypertensive, and 1K-1C hypertensive+DHA treated. Hypertension was induced in 1K-1C rats via placing a silver clip (0.20-mm ID) around the left renal artery following a right uninephrectomy. DHA (36 mg/kg/day) was given to the treatment groups for 60 days by gastric gavage. Arterial blood pressure was measured by using the tail-cuff method. Active avoidance responses were determined by an automated shuttle-box. In brain (cerebrum) and hippocampus tissues, thiobarbituric acid reactive substances (TBARS) and nitrite levels were measured by fluorometric methods. DHA supplementation decreased blood pressure in hypertensive rats. Data from active avoidance training indicated that performance of active avoidance learning tasks were significantly impaired in 1K-1C hypertensive rats, but was completely restored by DHA supplementation. Increased cerebrum TBARS levels in 1K-1C rats were abolished by DHA administration. Cerebrum nitrite levels were lower in the DHA, 1K-1C and 1K-1C+DHA treated groups compared to controls. Hippocampus nitrite levels were lower in DHA treated and 1K-1C hypertensive rats compared to controls and higher in 1K-1C+DHA treated rats compared to the 1K-1C group. Our data indicates that DHA supplementation improves the performance of active avoidance learning tasks which is impaired in experimental hypertension. These affirmative changes might be due to a DHA-induced decrease in lipid peroxidation which may in turn limit the consumption of nitric oxide (NO) which promotes active avoidance learning.

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PubMed2006

The role of docosahexaenoic acid on visual evoked potentials in one kidney-one clip hypertension.

PURPOSE: To investigate the effects of polyunsaturated fatty acid (PUFA) docosahexaenoic acid (DHA) on visual evoked potentials (VEPs) in a one kidney-one clip (1K-1C) hypertension model in rats. METHODS: Five experimental groups were formed: a control group, a sham group, a group supplemented with DHA, a 1K-1C group, and a 1K-1C + DHA group. The DHA groups were treated for 60 days. In the 1K-1C groups, the right kidney was removed and a silver clip with a 0.2-mm gap was placed on the left renal artery. RESULTS: The DHA-supplemented rats had lower blood pressure than their respective controls (p < 0.01). The increased brain and retina thiobarbituric acid reactive substances (TBARS) levels in hypertensive rats were abolished by DHA administration. The brain nitrite levels were lower in the DHA, 1K-1C and 1K-1C + DHA groups compared with the control group (p < 0.01), and the retina nitrite level was higher in the 1K-1C + DHA group compared with the DHA and 1K-1C groups (p < 0.01). There was an improvement of P(2), N(2) and P(3) components following DHA supplementation in 1K-1C hypertensive rats compared with the 1K-1C group. CONCLUSION: The present study suggests that DHA supplementation has the potential to prevent VEP changes caused by an experimental model of hypertension. This state might be related to the lipid peroxidation lowering effect of DHA.

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PubMed2003

The effect of different hypertension models on active avoidance learning.

This study tested the effects of different hypertension models on active avoidance learning in rats. Three-month-old male Wistar rats were divided randomly into six groups as follows: control (C), sham operated (sham), two kidney-one clip (2K-1C), one kidney-one clip (1K-1C), deoxycorticosterone-salt (DOCA), and N-omega-nitro-L-arginine-methyl ester (L-NAME) groups. Mean arterial blood pressures were significantly higher in four hypertensive groups compared with control and sham groups. The active avoidance training results indicated that hypertension state is associated with learning impairment. Thiobarbituric acid-reactive substances (TBARS) were determined as an indicator of lipid peroxidation in brain and hippocampus. Additionally, brain and hippocampus nitrite levels were studied.

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PubMed2002

The effect of different hypertension models on visual evoked potentials.

Even though there is an abundance of information about the complications of hypertension, studies of its influence on visual evoked potentials (VEPs) are rare. In previous studies, it was pointed out that hypertension induces changes on VEPs. However, it has not yet been clarified which models of hypertension are more effective on VEPs. The aim of this study was to investigate this subject in rats. Animals were divided equally into six groups: control group (C), sham operated (Sham), two kidney-one clip (2K-1C), one kidney-one clip (1K-1C), deoxycorticosterone-salt (DOCA), and N-omega-nitro-L-arginine-methyl ester (L-NAME) groups. Mean arterial pressure was significantly higher in four hypertensive groups compared with control and sham groups, but there were no significant differences either among hypertensive groups or between sham and control groups. At the end of the experimental period, flash visual evoked potentials were recorded. The mean latencies of P1, N1, P2, N2, and P3 components were significantly prolonged in all hypertensive groups compared with the control and sham groups. The mean latencies of all VEPs components in the L-NAME group were longer than in the other hypertensive groups. Thiobarbituric acid-reactive substances (TBARS) were determined as an indicator of lipid peroxidation. Our data showed that hypertension caused a significant increase of lipid peroxidation in brain and retinal tissues. Additionally, plasma renin activity (PRA) was highest in the 2K-1C group and lowest in the DOCA group.

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PubMed2002

Red blood cell rheological properties in various rat hypertension models.

Red blood cell (RBC) properties were proposed to play role in the development of hypertension (HT). This study aimed at investigating the alterations of RBC deformability and aggregation, in various models of HT in rats. The following four models of HT were developed in rats: one kidney-one clip HT (1K-1C HT), two kidney-one clip HT (2K-1C HT), deoxycorticosterone acetate (DOCA) induced HT (15 mg/kg, 2 times/week, sc) and N-nitro L-arginine methyl ester (L-NAME) induced HT (50 mg/kg/day, 10 weeks, ip). The blood samples were obtained from abdominal aorta, under ether anesthesia, after a period of 10 weeks of increased blood pressure. RBC deformability was determined by ektacytometry. RBC aggregation was measured in autologous plasma and 0.5% dextran 500, using a photometric rheoscope. Plasma fibrinogen concentration was determined by Clauss method. The mean blood pressure in all four HT models were about 140 mmHg, on the day of sampling, compared to approximately 110 mmHg in the control group. RBC deformability was found to be significantly decreased in the L-NAME model of HT. RBC aggregation in autologous plasma was significantly higher than control in 2K-1C, L-NAME and DOCA models, DOCA HT model being the most effective in altering the RBC aggregation. Plasma fibrinogen values were found to be higher than control in 2K-1C and L-NAME HT models, but not in DOCA HT. These results confirm that RBC rheological properties might be altered in HT. It can also be suggested that these alternations may not simply be the result of the vascular effects of HT, but may play role in the development of HT, as the alterations in different HT models were not the same, although the length and magnitude of increased blood pressure were similar.

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