Biomedical subjects

Zafer Yonden

Publications and source records attributed to Zafer Yonden.

5 recordsLinked to original sources

PubMed2004

NMDA receptor subunits 2A and 2B decrease and lipid peroxidation increase in the hippocampus of streptozotocin-diabetic rats: effects of insulin and gliclazide treatments.

Recent studies indicate that diabetes mellitus changes N-methyl-D-aspartate (NMDA) receptor subunit composition and impairs cognitive functions. It also has been known that diabetes mellitus causes lipid peroxidation. This study examined the effects of streptozotocin-diabetes and insulin or gliclazide treatment on the hippocampal NMDA receptor subunit 2A and 2B (NR2A and NR2B) concentrations. In addition, malondial dehyde (MDA) levels were measured as a marker for lipid peroxidation. Eight weeks after the induction of diabetes MDA, levels were increased, and NR2A and NR2B concentrations were reduced. Insulin and gliclazide treatment partially prevented the reduction of NR2A and NR2B expression and prevented the elevation of MDA levels. There was no significant difference between the effects of insulin and gliclazide. The results suggest that the elevation of lipid peroxidation can be the primary biochemical disturbances in diabetes progression, and that changes in NMDA receptor subunit compositions can be involved in cognitive decline in diabetes.

Animals↗

PubMed2004

Effects of dietary long chain PUFAs on hippocampal lipid peroxidation and NMDA receptor subunits A and B concentration in streptozotocin-diabetic rats.

This study examined the effects of streptozotocin (STZ)-diabetes and dietary long chain polyunsaturated fatty acids (LC-PUFAs) on hippocampal N-methyl-D-aspartate (NMDA) receptor subunit expression and lipid peroxidation. MDA level was significantly increased after 8 weeks of STZ-diabetes. LC-PUFAs administration significantly reduced MDA levels in diabetic rats. NR2A and NR2B protein concentrations were significantly decreased by about 30% in diabetic rats. Dietary LC-PUFAs partially restored NR2A and NR2B in diabetic rats whereas the most significant increase was seen in nondiabetic rats. Consequently, dietary LC-PUFAs can partially restore hippocampal NMDA receptors and decrease lipid peroxidation in diabetes. LC-PUFAs are thus a possible prophylactic means for preventing the cognitive deficiencies of diabetes.

Animals↗

PubMed2004

Lung injury after aortic occlusion-reperfusion in rats: the role of gadolinium chloride.

Aortic ischemia-reperfusion (AIR) induced lung injury has already been documented. Kupffer cell blockage (KCB) with gadolinium chloride (GdCl3) has also been shown to attenuate remote organ damage caused by ischemia reperfusion. The present study was designed to examine the effect of GdCl3 in lung ischemia-reperfusion injury induced by aortic occlusion. Thirty-two rats were randomly allocated to four groups as follows: SHAM (Sham Laparotomy), SHAM+KCB, AIR, and AIR+KCB. An atraumatic microvascular clamp was placed across the infrarenal abdominal aorta just after its origin from the aorta for 30 minutes. The microvascular clamp on the infrarenal abdominal aorta was removed and reperfused for 60 minutes. GdCl3 was given 24 hours prior to the experiment. Malondialdehyde (MDA) level and myeloperoxidase (MPO) activity were assayed in lung tissues. MDA level and MPO activity in the AIR group were significantly higher than those in the other groups. When compared to AIR group, KCB with GdCl3 significantly decreased MDA level and MPO activity in the AIR+KCB group. These results suggest that GdCl3 attenuates the lung injury caused by AIR. The effects of GdCl3 on reduced lung damage may be mediated through significant decreases in both MDA level and MPO activity.

Animals↗

PubMed2003

Ochratoxin A reduces NMDA receptor subunits 2A and 2B concentrations in rat hippocampus: partial protective effect of melatonin.

Ochratoxin A (OTA) is a mycotoxin produced by several fungi. Many foods can be contaminated by OTA, which is consequently found in the blood of humans and animals. It is known that OTA accumulates in the brain. The aim of this study was to investigate the effects of OTA on the brain. For this purpose, the effect of OTA on N-methyl-D-aspartate (NMDA) receptor subunits 2A (NR2A) and 2B (NR2B) in the hippocampus and the protective effect of melatonin were investigated. Three groups of eight rats were used: controls, OTA-treated rats (OTA dose 289 microg/kg per day) and OTA+melatonin-treated rats (melatonin dose 10 mg/kg per day). After four weeks of treatment, electrophoretic examinations were performed using SDS-polyacrylamide gel electrophoresis and Western blotting of hippocampal homogenates of the different groups. The concentrations of NR2A and NR2B in the OTA group were significantly lower than in the control group. The concentration of NR2B was significantly increased when melatonin was co-administered with OTA compared with OTA only. There was also a significant increase in NR2A levels when melatonin was co-administered with OTA. As a result, subchronic administration of OTA reduced hippocampal NMDA receptor subunits 2A and 2B concentrations in rats. It was thought that this alteration might affect cognitive functions because hippocampal NMDA receptors are involved in the memory and learning processes. Melatonin exhibited a partially protective effect on NR2A and NR2B against OTA.

Animals↗

PubMed2002

Effect of functional pinealectomy on hippocampal lipid peroxidation, antioxidant enzymes and N-methyl-D-aspartate receptor subunits 2A and 2B in young and old rats.

OBJECTIVES: To investigate the effects of pinealectomy on lipid peroxidation, antioxidant status and NMDA receptor subunits 2A and 2B concentrations in hippocampus. DESIGN: Forty-eight male Wistar-albino rats were used. SETTINGS: Animals were divided into three groups: 24 h dark throughout the study (highest melatonin release), 24 h light exposure (light-induced functional pinealectomy) and 12 h light/12 h dark exposure (control group). Thereafter, each group was divided into two groups as young and old animals. RESULTS: There was an increase in NR2A and NR2B concentration in DY group compared to all other treatments. CuZn and Mn SOD activities were found to be increased in CO compared to CY group. Continual light exposure for 4 weeks did not change neural CuZn and Mn SOD activities. In old rats, light exposure reduced the activities of both CuZn and Mn SOD relative to those in the young animals. In addition, CuZn and Mn SOD activities were higher in dark exposed rats than in those in the continual light exposed or LD 12:12 rats. GSH-Px activity was found elevated in the DY rats compared to the CY groups. MDA levels were significantly higher in the CO than in the CY group. CONCLUSIONS: NR2A and NR2B receptor concentrations in hippocampus of the rats maintained in dark showed significant increases compared to the control and functional pinealectomy groups but there was no significant increase in lipid peroxidation.

Aging↗