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    Chronic (3-Weeks) Treatment of Estrogen (17 beta-Estradiol) Enhances Working and Reference Memory in Ovariectomized Rats: Role of Acetylcholine
    (SPRINGER/PLENUM PUBLISHERS, 2016) Uzum, Gulay; Bahcekapili, Nesrin; Baltaci, Abdulkerim Kasim; Mogulkoc, Rasim; Ziylan, Yusuf Ziya
    Recently there has been a growing interest in the effects of estrogen on cognitive functions. In this study, we aimed to examine 17 beta-estradiol treatment on working and reference memory in ovariectomized rats. We also examined the changes in the acetylcholine (ACh) levels in the brain areas associated with learning and memory. The study was performed on Sprague-Dawley type 3-month-old female rats. The rats were divided into four groups as control, ovariectomy (OVX), and OVX and estrogen treatment (10 A mu g/day i.p. 17 beta-estradiol) groups for 3 (OVX + E3) and 21 days OVX + E21). The rats were trained on eight arm radial maze task with eight arms baited to assess spatial memory, in addition four arms baited to assess both working and reference memory performances. The electron microscope images of the ACh vesicles in the frontal cortex, temporal cortex and hippocampus areas of the brain which are important regions for learning and memory were screened. Results showed that long term 17 beta-estradiol treatment has positive effects on both reference memory and working memory and that ACh vesicles increased in the examined brain areas, especially in hippocampus. Our results suggest that 3 weeks 17 beta-estradiol treatment may have an ameliorative effect on the memory through the central cholinergic system.
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    Leptin transport in the central nervous system
    (WILEY, 2009) Ziylan, Yusuf Ziya; Baltaci, Abdulkerim Kasim; Mogulkoc, Rasim
    Synthesized and released by the adipose tissue, leptin is the widely studied 167-amino acid hormonal protein product of the obesity gene. Originally leptin was defined in association with satiety and energy balance and claimed to be an anti-obesity factor that functioned via a feedback effect from adipocytes to hypothalamus. There is a growing body of evidence that emphasizes the importance of leptin in the regulation of food intake and body weight in animals and humans, alike. Other research findings point out that it plays a role in the regulation of the metabolism, sexual development, reproduction, hematopoiesis, immunity, gastrointestinal functions, sympathetic activation, and angiogenesis. The aim of this review is to evaluate the relation between leptin and the central nervous system (CNS). Copyright (C) 2009 John Wiley & Soils, Ltd.
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    Pre- and post-estrogen administration in global cerebral ischemia reduces blood-brain barrier breakdown in ovariectomized rats
    (AKADEMIAI KIADO RT, 2015) Uzum, G.; Bahcekapili, N.; Baltacı, A. K.; Moğulkoç, Rasim; Ziylan, Yusuf Ziya
    The aim of present study was to determine the effect of estrogen treatment on blood-brain barrier permeability in rats with induced global cerebral ischemia. The study included six-month-old female Sprague-Dawley rats which were divided into the following groups: Control-Ischemia-Reperfusion (C + I-R); Ovariectomy-Ischemia-Reperfusion (Ovx + I-R); Ovariectomy + Estrogen + Ischemia-Reperfusion (Ovx + E + I-R); Ovariectomy + Ischemia-Reperfusion + Estrogen (Ovx + I-R + E). Ischemia-reperfusion was induced by clamping two carotid arteries, then opening the clamp. Blood-brain barrier permeability was visualized by Evans Blue extravasation and quantified by spectrophotometry. Our results indicate that following ischemia-reperfusion the BBB permeability is increased in ovariectomized rats (Evans Blue extravasation) compared to the control group in the cortex, thalamus, hippocampus, cerebellum and brain stem, while in the midbrain no significant increase was detected. In contrast, BBB permeability in the groups treated with estrogen, administered either before or after ischemia-reperfusion, was significantly lower than in ovariectomized animals. In conclusion, the increase in BBB permeability resulting from experimentally induced cerebral ischemia was prevented by exogenous estrogen treatment. The study results indicate that estrogen may be used for therapeutic purposes in ischemia-reperfusion.