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Öğe The effect of clomiphene citrate on osteoporosis in ovariectomized rats(2008) Uyar Y.; Koltan S.O.; Pögün Ş.; Vatansever S.; Çaglar H.Objective: The aim of this study was to investigate whether clomiphene citrate (CC) administration could be a new therapeutic agent in case of contraindication of estrogen therapy for hormone-dependent osteoporosis and to show the changes in bone structure by histomorphometric analysis in ovariectomized rats administered CC. Study design: This study was carried out in the Experimental Surgery Laboratory of the Brain Research Centre of the Medical Faculty of Ege University. Four-month-old Sprague-Dawley rats were used for the experiment. The study was carried out on six groups of animals each consisted of eight rats. Four groups of rats were ovariectomized and 2 groups of rats were used as control group. For 6 weeks every day, rats were injected physiological saline solution (1 ml/kg), clomiphene citrate (1 or 10 mg/1 ml/kg, Organon), 17ß-estradiol (50 µg/1 ml/kg, within susame oil, Sigma) or susame oil (1 ml/kg, Sigma). Drug administrations were carried out according to the weekly weight measurements. Group 1(PSS), n = 8, non-ovariectomized, were injected with physiological saline solution. Group 2(CC-1), n = 7, non-ovariectomized, were injected with CC (1 mg/1 ml/kg). Group 3(OVX + CC-1), n = 7, ovariectomized, were injected with CC (1 mg/1 ml/kg). Group 4(OVX + CC-10), n = 6, ovariectomized, were injected with CC (10 mg/1 ml/kg). Group 5(OVX + E), n = 8, ovariectomized, were injected with 17ß-estradiol (50 µg/1 ml/kg). Group 6(OVX), n = 8, ovariectomized, were injected with susame oil (1 ml/kg) Bone-specific serum alkaline phosphatase (ALP) levels were measured and statistical analyses were made by Kruskal Wallis test. Left femur bone histomorphometric studies were done. The uteri were dissected out to measure their weight and ANOVA was used to show the intergroup differences. Results: The level of ALP in group 3 was significantly higher than the other five groups. Bone histomorphometric examination showed that total bone volume in group 3, 4, and 5 was higher than group 6, and group 4 had the highest level of bone volume compared to the rest of the groups. Uterus weights in group 1 were significantly higher than group 3 and 6 (P = 0.02, P = 0.01) and uterus weights in group 5 were significantly higher than group 3 and 4 (P = 0.00, P = 0.01) Conclusions: In ovariectomized rats, treatment with CC is seen as effective as estrogen treatment in preventing osteoporosis, without causing uterin hyperstimulation. Nevertheless, further investigations on more rats are needed to assess whether it is an alternative treatment method to estrogen. © 2007 Springer-Verlag.Öğe Effects of nicotine on active avoidance learning in rats: Sex difference(1997) Yilmaz Ö.; Kanit L.; Okur B.E.; Pögün Ş.Nicotine, a cognition enhancer and a drug of abuse, exerts its central actions through neuronal nicotinic acetylcholine receptors which show sexual dimorphism. This study tested the effects of nicotine on active avoidance learning in male and female rats. Three month-old Sprague-Dawley rats received varying doses of nicotine (0.2, 0.4 and 0.6 mg/kg) or saline s.c. before active avoidance learning trials (15 trials/day) for a period of 5 days. Behavioural testing was continued after the termination of nicotine treatment once a week for four weeks. Nicotine improved acquisition of active avoidance learning in a dose-dependent manner. In male rats nicotine was active at all doses tested whereas, in females, learning performance deteriorated at a dose of 0.6 mg/kg. In conclusion, nicotine pre-treatment affects active avoidance in a sexually dimorphic and dose-dependent manner.Öğe Learning induces changes in the central cholinergic system of the rat in a sexually dimorphic pattern(1992) Pögün Ş.; Demirgören S.; Kutay F.Z.; Okur B.The involvement of the central cholinergic system in learning and the possible sexual dimorphism in related brain responses were investigated. Rats were exposed to different environmental conditions and to active avoidance learning. The resulting changes were studied using the following approaches: muscarinic receptor binding (MRB), acetylcholinesterase (AChE) and choline acetyltransferase (CAT) activities. The statistical evaluation of the data reveal that learning induces changes, especially in the postsynaptic component of the central cholinergic system, which shows some sexual dimorphism, and that males and females respond with different levels of increased cholinergic activity to informal and associative learning. © 1992.Öğe Nicotine interacts with sex in affecting rat choice between 'look-out' and 'navigational' cognitive styles in the morris water maze place learning task(1998) Kanit L.; Taşkiran D.; Furedy J.J.; Kulali B.; McDonald R.; Pögün Ş.The effect of sex and nicotine on cognitive style was examined in rats using a water maze task that allows differentiation between cognitive ability and style. During the 12-day acquisition period with the platform in the same location (either visible or hidden) there were no effects or interactions attributable to nicotine and sex, either in terms of learning rate or asymptotic latency. On the final test day the platform was visible and shifted in its location, and on the first trial the new location was proximal to the rats starting position, in contrast to the more distal location of the platform during the previous acquisition days. This platform relocation presented the rats with a choice between two competing cognitive styles: using local visual (look-out) cues vs. navigational cues. Performance on the test day yielded a nicotine x sex interaction, such that only saline-treated female rats showed a clear preference for the perceptual-proximal look-out cognitive style by swimming straight to the newly-relocated visible platform with mean escape latency that approximated the limits of swimming speed. The other three groups did not differ from each other, and preferred navigational cues. The results show that male and female rats use different strategies in problem solving, and that nicotine shifts the female pattern to that of the male.
