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Öğe Bioassay guided fractionation of extracts from flowers of Bellis perennis L. for their anticancer activity(Georg Thieme Verlag Kg, 2011) Karakaş, Pehlivan Fatma; Karakaş, Alper; Mshvildadze, V; Legault, J.; Pichette, A.; Türker, Uçar ArzuCommon daisy (Bellis perennis L.) is a member of the cosmopolitan family Compositae (Asteraceae). It is native to western, central, and northern Europe, but is commonly found as an invasive plant in North America (1). B. perennis has been used in the treatment of gastritis, enteritis, diarrhoea, bleeding, rheumatism, inflammation and infections of the upper respiratory tract (2–3). In this study, anticancer activity of crude hexane, dichloromethane, methanol, water extracts, also n-butanol and ethylacetate fractions (after separation of methanol extract) of flowers from Bellis perennis were investigated. Cytotoxic activities were carried out on human lung cancer (A549), human colorectal cancer (DLD-1), and normal skin fibroblasts (WS1) using the resazurin reduction test. Following the bioassay guided fractionation, the most active methanolic extract, was treated by n-butanol and ethylacetate. The n-butanolic fraction was found to be the most active against A-549 lung carcinoma and DLD-1 colon carcinoma cells, with IC50 values of 16±3 and 10±2µg/ml, respectively. The hexane, dichloromethane and water extracts did not show any significant activity against A-549 and DLD-1.Öğe Cytotoxic, anti-inflammatory and antioxidant activities of four different extracts of Galega officinalis L (goat's rue)(Pharmacotherapy Group, 2016) Karakaş, Fatma Pehlivan; Türker, Arzu Uçar; Karakaş, Alper; Mshvildadze, VakhtangPurpose: To evaluate the cytotoxic, anti-inflammatory and antioxidant activities of four different solvent extracts obtained from the aerial parts of Galega officinalis L. Methods: The hexane, DCM, methanol and water extracts of G. officinalis were successively obtained by soxhlet extraction method. The cytotoxic activity of the extracts was assessed against human lung carcinoma (A-549), human colorectal adenocarcinoma (HT-29), human brain glioblastoma (U-87), and colon adenocarcinoma (DLD-1) by Resazurine test. The antioxidant activity of extracts were determined by Folin-Ciocalteau, oxygen radical absorbing capacity (ORAC), and 2'.7'-dichlorofluorescin-diacetate (DCFH-DA) cell-based assay while their anti-inflammatory activity was determined by nitric oxide (NO) assay. Results: DCM extract showed strong cytotoxic activity against lung adenocarcinoma and brain glioblastoma cell lines, with IC50 (concentration inhibiting 50 % of cell growth) values of 11 +/- 0.4 and 16 +/- 3 mu g/mL, respectively. The hexane extract showed moderate anticancer activity against the same cell lines (59 +/- 13 and 63 +/- 16 mu g/mL, respectively). DCM extract also showed significant anti-inflammatory activity, inhibiting NO release by 86.7 % at 40 mu g/mL in lipopolysaccharide (LPS) - stimulated murine RAW 264.7 macrophages. Of all test extracts, the methanol extract of G. officinalis showed the highest antioxidant activity with 2.33 +/- 0.09 mu mol Trolox/mg, 7.10 +/- 0.9 g tannic acid equivalent (TAE), and IC50 of 44 +/- 4 mu g/mL. Conclusion: The findings of this study suggest that DCM extract may possess anticancer effect against lung adenocarcinoma and brain glioblastoma, as well as serve as an anti-inflammatory agent.Öğe Davranış bozuklukları ile mevsimsel ce sirkadiyen ritimler arasındaki ilişkinin fotoperiyod, suprakiyazmatik nukleus ve mikrodiyaliz çalışmaları çerçevesinde incelenmesi(2014) Karakaş, Alper; Gepdiremen, Ali Akçahan; Coşkun, Hamit; Yenisoy, Serpil Karakaş-Öğe Determination of melatonin hormone and neurotransmitters in cerebrospinal fluid: method validation and uncertainty calculations(Pleiades Publishing Inc, 2018) Çetin, Özge Yetgin; Karadeniz, Hatice; Karakaş, Alper; Karakaş, Serpil YenisoyThe uncertainty of measurement for well-known neurotransmitters like serotonin, noradrenalin and gamma-aminobutyric acid (GABA), glutamate and melatonin hormone with high performance liquid chromatography-fluorescence detection was calculated after the method validation. Two methods were developed for the determination of the neurotransmitters. A derivatization step was performed for the determination of GABA and glutamate. Sensitivity, method detection limit, limit of quantification, linearity, recovery, interday and intraday precision values were calculated. Low detection limit values were obtained especially for the determination of GABA and glutamate. Then, bottom-up approach was used to calculate measurement uncertainty. The critical stages of the method were evaluated. The major sources of the uncertainty budget were calibration curves, stock solution and recovery. The calculated percentage relative uncertainty values for the compounds changed between 10.1 and 16.7.Öğe Effect of different photoperiods on gonadal maintenance and development in mongolian gerbils (Meriones unguiculatus)(Zoological Soc Japan, 2002) Karakaş, Alper; Gündüz, BülentThe role of photoperiod in adult testicular maintenance and body weight and juvenile development was assessed in male Mongolian gerbils (Meriones unguiculatus). Gerbils were raised on a 14L (14 hr of light) photoperiod. In the first study, adult gerbils with functional testes were transferred to thirteen different photoperiods (0L, 2L, 4L, 6L, 8L, 10L, 12L, 14L, 16L, 18L, 20L, 22L, or 24L) and body weights and testicular size were measured every week for 10 weeks. Body weights were similar in all groups. Testicular regression had occurred in animals housed on 0L, 2L, 4L, 6L, 8L, and 24L by week 10. In the second study, 14L-born prepubertal gerbils were transferred to thirteen different photoperiods as in the first study. Body weights and testicular development were examined for 10 weeks. At the end of 10 weeks the body weights of animals in all groups except 24L were similar to those of adults. Animals in 24L had a lower body weight gain. Exposure to 0L, 2L, and 24L inhibited testicular development and testes weights were significantly different from those of the other groups. These results demonstrate that maintenance of body weight in adult gerbils appears to be independent of photoperiodic signal. Exposure to very long (24L) and short photoperiods (<10 hr) causes testicular regression in adult gerbils. Moreover, different photoperiods experienced in early life can influence prepubertal testis growth and body weight gain.Öğe The effect of pinealectomy and leptin hormone on the proliferation and apoptosis activation in Syrian hamster testis in different photoperiods(Wiley-Blackwell Publishing, Inc, 2009) Gündüz, Bülent; Karakaş, Alper; Terzi, Hakan; Öner, Jale; Serin, Erdinç; Kükner, AyselP>The effects of pinealectomy and leptin hormone on proliferative and apoptotic processes in the epithelia of testicular seminiferous tubules of Syrian hamsters have been investigated. Proliferative and apoptotic processes were assessed semi-quantitatively by proliferating cell nuclear antigen (PCNA) and caspase-3 immune stainings. Animals used in the study were divided into four groups; control, pinealectomy (PinX), leptin-treated (10 mu g/mL/day/kg body weight, intraperitoneally) and pinealectomy + leptin groups. Half of the hamsters in each group were exposed to short and the other half to long photoperiods for 8 weeks. In short photoperiod, PCNA activity especially in spermatogonia was significantly higher in the pinealectomy and leptin-treated groups compared with the control group. Histological score (HSCORE) value of PCNA in the PinX + leptin group was lower than those of PinX and leptin-treated groups. HSCORE value of caspase-3 in PinX and PinX + leptin groups was increased. In the long photoperiod, PCNA activation in the PinX group was significantly lower than the control group while the differences between the controls and other groups were not significant. The difference between the increases in caspase-3 activity in the PinX and control groups was significant. Thus, it was observed that photoperiods had no effect on the proliferation activity in the control groups. The inhibiting effect of short photoperiod on testis was not observed throughout 8 weeks. PinX eliminated the inhibiting effect of short photoperiod but did not alter the stimulating effect of long photoperiod. Leptin did not show any effect in long photoperiod but decreased proliferation by stimulating melatonin in short photoperiod.Öğe The effect of pinealectomy, melatonin and leptin hormones on ovarian follicular development in female Syrian hamsters (Mesocricetus auratus)(Akademiai Kiado Zrt, 2010) Karakaş, Alper; Kaya, Aliye; Gündüz, BülentWe studied the effects of melatonin and leptin hormones on ovarian follicular development in intact and pinealectomized female Syrian hamsters. We first monitored the oestrous cycle of the hamsters by the vaginal smear samples throughout a ten day period to start the injections simultaneously in all groups and performed saline, melatonin and leptin hormone injection groups for both control and pinealectomized hamsters. Then the injections were applied for four days starting the oestrus phase of the cycle and the ovaries were removed for preparation of histological analysis. We measured the diameters and the numbers of the follicles and we classified the follicles according to the number of the granulosa cell layer. Leptin hormone injection increased melatonin hormone injection decreased the number and the diameter of the follicles. The stimulating effect of the leptin hormone was more pronounced in the pinealectomized group. The results of the present study indicate that the removal of the pineal gland and leptin hormone administration are playing a stimulatory while melatonin hormone administration is playing an inhibitory role on the follicular development in female Syrian hamsters.Öğe Effects of European mistletoe (Viscum album L. subsp album) extracts on activity rhythms of the Syrian hamsters (Mesocricetus auratus)(Taylor & Francis Ltd., 2008) Karakaş, Alper; Türker, Arzu Uçar; Gündüz, BülentAntitumor drugs may have some significant nervous system side-effects such as disrupted sleep, eating and drinking patterns. European Mistletoe has been investigated for many decades for its potential use against cancer. To test the hypothesis that the non-antineoplastic effects of mistletoe might be mediated by the actions on the circadian timing system, we have applied mistletoe extracts and vehicle and have measured locomotor activity, feeding and drinking rhythms under constant darkness. Four groups (vehicle, 20 mg kg(-1) ip injection, 40 mg kg(-1) ip injection and 6 g kg(-1) oral administration) were performed for both heat-treated and freeze-dried extracts. None of the administrations changed the locomotor activity, feeding and drinking rhythms in the groups except for 40 mg kg(-1) freeze-dried injected group. The locomotor activity levels decreased in 40 mg kg(-1) freeze-dried extract injected group. These results suggest that, side-effects of mistletoe on circadian timing system of the Syrian hamster depend on the dose and the preparation method of the extract.Öğe The effects of leptin hormone on locomotor activity in Syrian Hamsters (Mesocricetus Auratus)(2011) Gündüz, Bülent; Karakaş, AlperThe suprachiasmatic nucleus (SCN) generates and controls the circadian rhythms in mammals including the rhythm of locomotor activity. Leptin is a hormone secreted by adipose tissue that informs the brain about the fat stores. SCN neurons express leptin receptors. Here we investigated the effects of 3 different leptin administrations on the locomotor activity of the Syrian hamsters maintained in constant darkness. Animals were intraperitoneally (ip) injected (4 μg/kg), subcutaneously (sc) infused (4 μg/kg), or intra-SCN infused (0.4 μg/kg) with leptin for 3 days at circadian time 10 whereas the controls received saline (0.9% NaCl) at the same time in order to eliminate stress factors. Our results demonstrate that the locomotor activity of the hamsters can be phase advanced by the external leptin administrations. Leptin affected the level of phase-shifts in an administration method-dependent manner. The biggest phase advance was observed in intra-SCN infusion (P = 0.001), and the smallest was in the ip injection (P = 0.041) group. The wheel-turn amounts did not change significantly in the groups before and after the leptin administrations (P = 0.233); however, the period lengths increased (P = 0.011) significantly after leptin administrations. These results suggest for the first time that in vivo leptin administrations may change the rhythm of locomotor activity in adult male Syrian hamsters.Öğe The effects of mistletoe (Viscum Album L. Subsp. Album) extracts on isolated intestinal contractions(2008) Karakaş, Alper; Serin, Erdinç; Gündüz, Bülent; Türker, Arzu UçarThroughout history folk medicine has served as an alternative or complimentary method of treating disorders like intestinal colic. Mistletoe is a common name for many species of semi-parasitic plants that grow on trees throughout the world, and has been used widely to treat intestinal colic. We conducted a study to evaluate the effect of freeze-dried (group 1) and heat-treated (group 2) extracts of Viscum album subsp. album leaves on contractions induced by acetylcholine in isolated hamster intestinal segments (duodenum, jejunum, and ileum). Freeze-dried extracts decreased intestinal contractions in all the intestinal segments (P < 0.05). The strongest relaxant effect was observed in the jejunum and the weakest was seen in the duodenum. Higher doses of heat-treated extracts were required to affect segmental contractions than that of freeze-dried extracts (P < 0.05); heat-treated extracts had the greatest effect on reducing contractions in the jejunum and the least effect in the duodenum. Mistletoe extracts affected the level of contractions in a dose- and extraction preparation-dependent manner. The results of this study show that mistletoe extracts could be effective against intestinal motility problems and that they have potential use as a therapeutic remedy for intestinal colic.Öğe The effects of mistletoe (Viscum album L. subsp. album) extracts on ısolated ıntestinal contractions(2008) Karakaş, Alper; Serin, Erdinç; Gündüz, Bülent; Türker, Arzu UçarHalk ilaçları eski çağlardan bu yana bağırsak ağrıları gibi problemlerin tedavi edilmesinde alternatif ya da tamamlayıcı bir yol olmuşlardır. Ökseotu, tüm dünyada, ağaçlarda büyüyen gelişen yarı parazit bir bitkidir ve bağırsak kasılmalarına karşı yaygın olarak kullanılmaktadır. Çalışmamızda Viscum album subsp. album yapraklarının, bitkisinden dondurulup-kurutulma (Grup 1) ve sıcak su (Grup 2) ile ekstraksiyon suretiyle hazırlanan ekstraktların, izole edilmiş ince bağırsağın farklı segmentlerinde (duodenum, jejunum, ileum) asetilkolin ile oluşturulmuş kasılmalar üzerine olan etkilerini inceledik. 1. Gruptaki ekstraktlar tüm bağırsak segmentlerinde kasılmaları düşürdü (P < 0.05). En güçlü gevşetici etki jejunumda, en düşük etki ise duodenumda gözlendi. 2. Gruptaki ekstraktlar 1. Gruptaki ekstraktlardan daha yüksek dozlarda segmental kasılmaları etkiledi (P < 0.05); kasılmalardaki düşüş jejunumda daha fazla, daha düşük ileum ve en düşük etki duodenumda gözlendi. Ökseotu ekstraktlarının kasılmaları doza ve hazırlama yöntemlerine bağlı olarak etkilediği görülmektedir. Sonuç olarak ökseotu ekstraktları bağırsak hareket problemlerine karşı etkili olabilmekte ve bağırsak kasılmalarında tedavi edici ilaç olarak bir potansiyeli bulunmaktadır.Öğe The effects of mistletoe (Viscum album L.) extracts on isolated ileum contractions(Amer Assoc Clinical Chemistry, 2006) Serin, Erdinç; Karakaş, Alper; Türker, Arzu; Gündüz, BülentEuropean mistletoe (Viscum album L, Loranthaceae) is an evergreen, semiparasitic plant normally found growing on a variety of trees. Both in viva and in vitro studies have shown the cytotoxic, cardiotoxic, immunostimulant, hypoglycemic, antitumor and vasodilator effects of the extracts produced from this plant.Öğe The effects of photoperiod and age on food anticipatory activity in Mongolian gerbils (Meriones unguiculatus)(Taylor & Francis Ltd, 2011) Karakaş, AlperIn many animal models, the circadian rhythm of locomotor activity is regulated by at least two external pacemakers, environmental photoperiod and food availability. Entrainment with food is characterized by an anticipatory increase in locomotor activity before mealtime. In the present study, the effects of photoperiod and age on the food anticipatory activity (FAA) of Mongolian gerbils were investigated. The experiments were performed under long (14L:10D) and short photoperiods (8L:16D) in young (3 months old) and old (2 years old) adult male gerbils. Food was given only for two hours (11 am-1 pm) during the light phase. Food restriction created FAA in the gerbils. The wheel turn performance of the gerbils was affected by photoperiod, age of the gerbil and food restriction in both light and dark phases. The gerbils experiencing the short photoperiod did perform better than those experiencing the long photoperiod. Young gerbils did perform better than old ones. The light/dark ratio in locomotor activity was affected significantly by photoperiod and food restriction. Food intake of the gerbils was affected by photoperiod, age, and food restriction. In conclusion, photoperiod, age of the gerbil and the food availability were found to be effective in the regulation of FAA in Mongolian gerbils.Öğe Effects of photoperiod and food availability on growth, leptin, sexual maturation and maintenance in the Mongolian gerbils (Meriones unguiculatus)(Zoological Soc Japan, 2005) Karakaş, Alper; Çamsarı, Çağrı; Serin, Erdinç; Gündüz, BülentReproductive activity of Mongolian gerbils is regulated by photoperiod nevertheless body weight regulation is controlled without ambient photoperiod. Food intake is a major factor affecting rodent reproductive efficiency. Leptin is a hormone secreted by adipose tissue and modulates food intake, energy expenditure and body fat stores. In this study we studied the interaction of photoperiod and food availability on growth, sexual maturation and leptin concentration in the male and female gerbils. Gerbils were gestated and reared in either 14L:10D or 2L:22D. At weaning, gerbils were housed individually and divided into three groups: fed ad libitum, fed 80% of ad libitum or fed 60% of ad libitum. Body weights were recorded at weaning and every week thereafter. After twelve weeks of treatment, animals were sacrificed and testes and uterine weights were determined and blood was collected for leptin measurement. Food restriction reduced body weight and inhibited reproductive development. Absolute paired testis weights were similar in ad lib and 80% of ad lib groups but significantly different compared with the 60% of ad lib group in both photoperiods. Body weights were also directly dependent upon the level of food restriction. Uterine mass was only affected in the 60% of ad lib group in 14L but both food restriction levels significantly affected the uterine weights in 2L. Significant variations were found in leptin profiles. Leptin concentration was highest in ad lib and 80% of ad lib groups and lowest in 60% of ad lib groups. These results suggest that the reproductive activity of Mongolian gerbils is sensitive to food intake and multiple potential environmental cues (e.g., food availability, temperature) can be utilized.Öğe Effects of photoperiod and melatonin infusions on body weight in pinealectomized juvenile siberian hamsters (Phodopus Sungorus)(2001) Gündüz, Bülent; Karakaş, AlperWe examined the effects of daily melatonin (Mel) infusions in pinealectomized prepubertal male Siberian hamsters in three different conditions. In one study we investigated the body weight maturation response to one hour daily infusions of 10 ng, 25 ng, or 50 ng of Mel in pinealectomized hamsters. Animals received, at day 15 of life, programmed subcutaneous infusions of Mel or vehicle at one of five time points (1900-2000, 2000-2100, 2100-2200, 2400-0100, and 0300-0400 hours) for 30 days. In long-day-born (16L) animals, Mel infusion right after lights off (2000-2100 hours) significantly inhibited body growth; this dose was ineffective at other times. Doses of 10 ng and 25 ng Mel were ineffective at all time points. In a second study, hamsters received either 4-or 8-h infusions of Mel (either 50 ng/h or 50 ng/day) at various times throughout the day and night of a 16L or 10L photoperiod. Daily 4-h, 50 ng/h, Mel infusions at 1700-2100 hours inhibited body weight growth in 16L and daily 4-h Mel infusions (either 50 ng/h or 50 ng/day) inhibited body weight growth at 1700-2100 hours in 10L. In all cases, daily 8-h infusions suppressed body weight development. In a third study, long-day-born pinealectomized hamsters were infused with two signals of four hours separated by an interval of two hours. Mel infused groups had significantly inhibited body growth compared to vehicle infused animals. Body weight development was maximally inhibited only in those groups in which the period of Mel sensitivity was identified in the first study (2000-2100 hours) overlapped or immediately followed a period of Mel infusion These results show that the photoperiodic body weight response in juvenile Siberian hamsters is regulated by the coincidence in time of exogenously administered Mel with an intrinsic rhythm of sensitivity to Mel, and the duration of the Mel signal alone cannot explain the results.Öğe The effects of pinealectomy and melatonin implants on circadian locomotor activity responses of the Mongolian Gerbils exposed to rapid photoperiodic transitions(2010) Gündüz, Bülent; Karakaş, AlperJet-lag sendromu ve vardiyalı çalışma rahatsızlığı fotoperiyoddaki hızlı değişimlerden kaynaklanır ve sıklıkla insanların hayatını olumsuz etkilemektedirler. Bu çalışmada jet-lag ve vardiyalı çalışma simüle edilmek istendi. Moğolistan gerbillerinin fotoperiyod değişimlerine karşı gösterdiği yeni ritim düzenlemesinde fotoperiyod, pineal bez ve melatonin hormonunun etkilerini araştırmak üzere, kontrol, pinealektomi ve melatonin implantları içeren gerbil grupları sırası ile uzun (14L:10D), kısa (8L:16D), sürekli karanlık (0L:24D) ve sürekli aydınlık (24L:0D) fotoperiyodlarına yerleştirildi. Gerbiller uzun ve kısa fotoperiyodlarda ışık/karanlık siklusu ile düzenlenen bir aktivite ritmi gösterirken, sürekli karanlıkta serbest koşu ve sürekli aydınlıkta ise aritmik bir aktivite vardı. Grupların periyod uzunlukları arasında anlamlı bir farklılık yoktu (p>0,05). Gerbillerin aktivitesi fotoperiyod değişiklikleri ile yeniden düzenlenirken, pinealektomi ve melatonin implantları ise bu düzenleme üzerine anlamlı bir etki yapmadı (p>0,05). Lokomotor aktivite miktarları fotoperiyod ve gruba bağlı olarak değişimler gösterdi. Bu çalışmanın sonuçları Moğolistan gerbillerinde lokomotor aktivite ritminin düzenlenmesinde fotoperiyodun etkili ancak pineal bez ve sürekli salınım yapan melatonin implantlarının ise etkili olmadığını gösterdi.Öğe The effects of pinealectomy, melatonin injections and implants on the spatial memory performance of male Wistar rats(Taylor & Francis Ltd, 2011) Karakaş, Alper; Coşkun, Hamit; Kaya, AliyeMelatonin is the main hormone of the pineal gland that informs the body about the environmental light and darkness regimen and is considered to regulate many important physiological and behavioural activities. In the present study, we examined the effects of pinealectomy, constant-release melatonin implants and timed melatonin injections on spatial memory in male Wistar rats by using Morris water maze. Pinealectomy, melatonin injection and melatonin implantation were performed on groups, including controls for all groups. After a week of the pinealectomy and melatonin implantation surgeries, we applied the injections and made the training trials throughout 4 days. At the fifth day, experiments were performed and recorded. Spatial memory performance of the rats was impaired by the pinealectomy and melatonin injections, since they elongated the latency and shortened the time passed in the correct quadrant. Melatonin implantation did not affect the spatial memory performance of the rats. The latency and the time passed in correct quadrant were not statistically different from their controls. The results suggest that while the removal of the pineal gland and exogenous administration of melatonin via injections are causing impairment, constant-release melatonin administration via implantation does not affect the spatial memory in Wistar albino rats.Öğe The effects of the intraamygdalar melatonin injections on the anxiety like behavior and the spatial memory performance in male Wistar rats(Elsevier, 2011) Karakaş, Alper; Coşkun, Hamit; Kaya, Aliye; Küçük, Ayşegül; Gündüz, BülentIn the present study, the effects of intraamygdalar administrations of melatonin (1 and 100 mu g/kg), saline and diazepam on the anxiety-like behavior and spatial memory performance in pinealectomized and sham-pinealectomized Wistar rats were investigated. The animals were tested by open field and elevated plus maze tests for anxiety-like behavior, and Morris water maze test for spatial memory. In open field, (a) diazepam was more effective in reducing the anxiety, (b) control subjects were more mobile than pinealectomized subjects and (c) 100 mu g/kg melatonin administrations reduced the velocity of the animals. In elevated plus maze, (a) 100 mu g/kg melatonin administrations increased the distance totally travelled and (b) enhanced the time spent in open arms, however, after the pinealectomy, 1 mu g/kg melatonin administrations decreased it and (c) control animals were less mobile than pinealectomized ones. In Morris water maze, (a) diazepam group travelled more distance than the others in control condition whereas, in pinealectomy condition high dose of melatonin and saline groups travelled more distance than the others, (b) in pinealectomy condition subjects who received 100 mu g/kg melatonin also travelled more distance than those who received 1 mu g/kg melatonin and diazepam, (c) the subjects who received 1 mu g/kg spent less time than those who received other treatments, and (d) in control condition subjects who received 100 mu g/kg melatonin were slower than those who received the other treatments. In conclusion, melatonin administration to amygdala decreased the anxiety; however, spatial memory performance of the rats was impaired by the pinealectomy and melatonin administrations. (C) 2011 Elsevier B.V. All rights reserved.Öğe The effects of the time of the day and the pinealectomy on anxiety-like behaviour in male Wistar rats(Taylor & Francis Ltd, 2011) Kaya, Aliye; Karakaş, Alper; Coşkun, HamitThe previous studies on the anxiety-like behaviour in rats by using elevated plus maze and open field have provided rather unequivocal results because they obtained data at different times of the day. These studies have never investigated the effects of the different times of day in a single research paradigm even though the results of such studies are generally attributed to the different measurement times. Thus, we aimed to examine the effects of the time of the day and the pinealectomy on anxiety-like behaviour in male Wistar albino rats by using elevated plus maze and open field in this study. Experiments were performed with control and pinealectomy groups at the four different time points (6:00, 12:00, 18:00 and 24:00 hr; LD 12:12, lights on at 6:00 h and off at 18:00 h). In open field, the main effect of the measurement time was significant on the total distance travelled, the mobility and the velocity. In elevated plus maze, the main effect of the measurement time was significant on the total distance travelled, the total entry to closed arms and mobility. The main effect of the pinealectomy was insignificant on all of the measured parameters in both open field and elevated plus maze except for the total entry to closed arms in elevated plus maze. The results of the present study showed for the first time that the time of the day when the measurements are performed is important on the anxiety-like behaviour of the Wistar albino rats.Öğe The effects of the weekend phase delay like shifts on spatial learning performances of the Wistar rats: the sex and generation differences(Taylor & Francis Ltd, 2012) Coşkun, Hamit; Karakaş, Alper; Kaya, AliyeMany people regularly wake up early in the morning on week days; however, during weekends, they stay awake late into the night and wake up late, thus representing a phase delay in their locomotor activity and sleeping pattern. We suggest that these phase delays on weekends may affect the spatial memory performance at the first couple of days in the following week. In the present study, we aimed to investigate the effects of the weekend phase delays on spatial memory performance of the Wistar albino rats at the beginning of the coming week by using Morris water maze. Control and phase delay groups were performed for both juvenile and adult rats in males and females. After eight weeks of the experimental phase delays, Morris water maze experiments were performed. Locomotor activity rhythms of the rats were also examined. The adult rats showed better learning performances in the total distance travelled and latency than the juvenile ones. However, juvenile rats entered and spent more time in the correct quadrant than adult ones. Phase delays reduced the velocity of the rats. The interaction effects among the phase delays, generation and sex were also significant. The findings of the present study showed that the phase delays at the weekends as well as their interaction with sex and generation are important on the learning performances of the Wistar albino rats.
