Person: KARAMAHMUTOĞLU, TUĞBA
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KARAMAHMUTOĞLU
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TUĞBA
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Publication Metadata only EFFECTS OF KINDLING STIMULATIONS ON TYROSINE HYDROXYLASE IMMUNOREACTIVITY IN SUBSTANTIA NIGRA PARS RETICULATA OF GAERS AND WISTAR RATS(2013-06-27) GÜLÇEBİ İDRİZ OĞLU, MEDİNE; KARAMAHMUTOĞLU, TUĞBA; ONAT, FİLİZ; GÜLÇEBİ İDRİZ OĞLU M., AKMAN Ö., ÇARÇAK YILMAZ N., KARAMAHMUTOĞLU T., ONAT F.Publication Metadata only Electroencephalographic and behavioral effects of intracerebroventricular injection of grayanotoxin in adult Wistar rats(2011-08-28) KARAMAHMUTOĞLU, TUĞBA; GÜLÇEBİ İDRİZ OĞLU, MEDİNE; ONAT, FİLİZ; HALAÇ H. M. , TEMİZ G., KURU P., TORUN M., İSKENDER E., KARAMAHMUTOĞLU T., GÜLÇEBİ İDRİZ OĞLU M., ONAT F.Publication Metadata only Suppressive effect of Rho-kinase inhibitors Y-27632 and fasudil on spike-and-wave discharges in genetic absence epilepsy rats from Strasbourg (GAERS)(SPRINGER, 2018) ONAT, FİLİZ; Carcak, Nihan; Yavuz, Melis; Karamahmutoglu, Tugba Eryigit; Kurt, Akif Hakan; Kucuk, Meral Urhan; Onat, Filiz Yilmaz; Buyukafsar, KansuRho/Rho-kinase (ROCK) signaling contributes to neuroinflammation, epileptogenesis, and seizures in convulsive-type epilepsies. However, this pathway has not been investigated in absence epilepsy. We investigated RhoA activity in genetic absence epilepsy rats from Strasburg (GAERS) and the effects of ROCK inhibitors Y-27632 and fasudil on spike-and-wave discharges (SWDs) of GAERS. ROCK level and activity were measured by Western blot analysis in the brain areas involved in absence seizures (i.e., cortex and thalamus) and hippocampus. Male GAERS were stereotaxically implanted with bilateral cortical electrodes for electroencephalogram (EEG) recordings and/or guide cannula into the right ventricle. ROCK inhibitors were administered by intraperitoneal injection (1-10mg/kg for Y-27632 or fasudil) or intracerebroventricular injection (7-20nmol/5l for Y-27632 or 10-100nmol/5l for fasudil). EEG was recorded under freely moving conditions. Compared with Wistar rats, GAERS exhibited increased RhoA activity in the somatosensory cortex but not in the thalamus or hippocampus. The single systemic administration of Y-27632 and fasudil partially suppressed the duration and frequency of absence seizure, respectively. However, local brain administration caused a widespread suppressive effect on the total seizure duration, number of seizures, and the average individual seizure length. In summary, Rho/ROCK signaling may be involved in the pathophysiology of absence epilepsy. Furthermore, ROCK inhibitors can control the expression of absence seizure in GAERS, thus indicating that Y-27632 and fasudil have the potential to be used as novel anti-absence drugs.Publication Metadata only Electroencephalographic and behavioral effects of intracerebroventricular or intraperitoneal injections of toxic honey extract in adult Wistar rats and GAERS(SPRINGER-VERLAG ITALIA SRL, 2014) ONAT, FİLİZ; Kuru, Pinar; Torun, Merve; Halac, Hande Melike; Temiz, Gozde; Iskender, Ece; Karamahmutoglu, Tugba; Idrizoglu, Medine Gulcebi; Onat, Filiz YilmazToxic honey, containing grayanotoxin, is obtained from nectar and polen of rhododendron. Consumed in excess it produces seizures and convulsions. In order to investigate whether the toxic honey extract can be used as a seizure model, we examined the electroencephalographic (EEG) and motor effects of intracerebroventricular (icv) or intraperitoneal (ip) injection of toxic honey extract in Wistar rats or in genetic absence epilepsy rats from Strasbourg (GAERS). Male Wistar rats or GAERS were stereotaxically implanted with bilateral cortical recording electrodes in all ip groups and cannula in the icv groups. Based on the previous study, an extract was obtained from the non-toxic and toxic honey. After the injection of the non-toxic or toxic honey extract, seizure stages and changes in EEG were evaluated from 9 am to noon. The icv administration of toxic honey extract produced stage 4 seizures and bilateral cortical spikes within 30-60 min and these effects disappeared after 120 min in Wistar rats or GAERS. The mean of bilateral cortical spike acitivity in EEG of Wistar rats was 804.2 +/- A 261.0 s in the 3-h period. After the icv administration of toxic honey extract to GAERS, the mean duration of spike-and-wave discharges (SWDs) in GAERS significantly decreased during the first 60 min and then returned to baseline level. Ip injection of toxic honey extract caused no seizure and no change in EEG in either GAERS or Wistars. These results suggest that the icv administration of toxic honey extract can be used as a seizure model.Publication Open Access Effects of Probiotic Consumption on Absence Seizures(KARE PUBL, 2017) ONAT, FİLİZ; Akkol, Serdar; Dogan, Mehmet Can; Esenkar, Duygu; Dogan, Handan; Karamahmutoglu, Tugba; Onat, FilizObjectives: Probiotics are microorganisms of intestinal microflora that are beneficial for human health. Childhood absence epilepsy has 2 validated rat models: Genetic Absence Epilepsy Rats from Strasbourg (GAERS) and Wistar Albino Glaxo from Rijswijk (WAG/Rij). To date, there have been no clinical or experimental studies of the effects of probiotics on absence epilepsy. The present study was an investigation of the effects of probiotics on absence seizures in the GAERS rat model. Methods: GAERS were used to examine the effects of probiotics. Nine male GAERS were assigned to 1 of 2 groups (probiotic or control). The animals had free access to food and water. Commercially available probiotic product was provided in drinking water to probiotic group for 1 month. Surface electrodes were then implanted for electroencephalogram (EEG) recordings. Two aspects of EEG recordings were compared: cumulative duration and cumulative number of absence seizures. Results: Analysis of spike-and-wave discharges between the 2 groups showed no significant difference in either cumulative duration or number (p>0.05). Additionally, it was observed that probiotic group consumed more water than control group (p<0.05). Conclusion: Results indicated that probiotic consumption had no effect on duration or number of spike-and-wave discharges of GAERS after 1-month feeding period. This is the first investigation in the literature addressing interactions between probiotics and absence epilepsy, and further research is needed.Publication Open Access Electron microscopic GABA evaluation in hippocampal mossy terminals of genetic absence epilepsy rats receiving kindling stimulations(2022-12-01) KAYA, ÖZLEM TUĞÇE; TURGAN AŞIK, ZEHRA NUR; KARAMAHMUTOĞLU, TUĞBA; GÜLÇEBİ İDRİZ OĞLU, MEDİNE; AKAKIN, DİLEK; ŞİRVANCI, SERAP; İmdat N. N., KAYA Ö. T., TURGAN AŞIK Z. N., ERYİĞİT KARAMAHMUTOĞLU T., GÜLÇEBİ İDRİZ OĞLU M., AKAKIN D., ONAT F., ŞİRVANCI S.Objective: The hypotheses related to the fact of epileptic mechanisms are mainly based on excitation-inhibition imbalance in central nervous system. GAERS (Genetic Absence Epilepsy Rats from Strasbourg) is a well-known animal model of absence epilepsy, and frequently used in experimental studies. In the present study, we aimed to examine possible morphological and gamma-aminobutyric acid (GABA) density changes in GAERS hippocampus after electrical kindling stimulations. Methods: All control and test group rats received 6 kindling stimulations. Rats were decapitated 1 h after the last stimulation. Ultrastructural GABA immunocytochemistry was used to evaluate GABA density quantitatively in mossy terminals of hippocampal CA3 region. Results: GABA levels were less in kindling groups compared to their controls, and in GAERS groups compared to Wistar groups; mitochondrial and dendritic spine area ratios were greater in GAERS groups compared to Wistar groups, although all these evaluations were statistically nonsignificant. Depletion of synaptic vesicles was evident in the mossy terminals of kindling groups. Conclusion: The reason of decreased levels of GABA found in the present study might be that GABA has been released from the synaptic pool rapidly at an early time period after the last stimulation, for compansation mechanisms. Depletion of synaptic vesicles observed in kindling groups shows that even 6 kindling stimulations have an impact of changing hippocampal morphology in trisynaptic cycle. The increased mitochondrial area in GAERS might be related to the increased mitochondrial activity. The increased dendritic spine area might be related to the increased performance of learning in GAERS. Our findings indicating that absence epilepsy and temporal lobe epilepsy have different mechanisms of epileptogenesis might be a basis for further experimental studies.Publication Metadata only Vücut ağırlığı değişimi genetik absans epilepsili sıçan yavrularında 6-hidroksidopamin kaynaklı nörodejenerasyon derecesini gösterebilir mi(2021-05-27) KARAMAHMUTOĞLU, TUĞBA; GÜLÇEBİ İDRİZ OĞLU, MEDİNE; GÜLHAN, REZZAN; ÇULPAN Y., KARAMAHMUTOĞLU T., TURGAN AŞIK Z. N., YAVUZ M., TOPLU A., GÜLÇEBİ İDRİZ OĞLU M., GÜLHAN R., ONAT F.Publication Metadata only Ultrastructural GABA immunogold labeling in the substantia nigra pars reticulata of kindled genetic absence epilepsy rats(TAYLOR & FRANCIS INC, 2020) AKAKIN, DİLEK; Sirvanci, Serap; Akakin, Dilek; Idrizoglu, Medine Gulcebi; Kaya, Ozlem Tugce; Karamahmutoglu, Tugba; Asik, Zehra Nur Turgan; Onat, FilizGenetic Absence Epilepsy Rats from Strasbourg (GAERS) is a well-known animal model of absence epilepsy and they are resistant to electrical kindling stimulations. The present study aimed to examine possible differences in gamma-aminobutyric acid (GABA) levels and synapse counts in the substantia nigra pars reticulata anterior (SNRa) and posterior (SNRp) regions between GAERS and Wistar rats receiving kindling stimulations. Animals in the kindling group either received six stimulations in the amygdala and had grade 2 seizures or they were kindled, having grade five seizures. Rats were decapitated one hour after the last stimulation. SNR regions were obtained after vibratome sectioning of the brain tissue. GABA immunoreactivity was detected by immunogold method and synapses were counted. Sections were observed by transmission electron microscope and analyzed by Image J program. GABA density in the SNRa region of fully kindled GAERS and Wistar groups increased significantly compared to that of their corresponding grade 2 groups. The number of synapses increased significantly in kindled and grade 2 GAERS groups, compared to kindled and grade 2 Wistar groups, respectively, in the SNRa region. GABA density in the SNRp region of kindled GAERS group increased significantly compared to that of GAERS grade 2 group. In the SNRp region, both kindled and grade 2 GAERS groups were found to have increased number of synapses compared to that of GAERS control group. We concluded that both SNRa and SNRp regions may be important in modulating resistance of GAERS to kindling stimulations.Publication Metadata only Structured Light Sheet Microscopy for High Contrast 3D Imaging of Whole Mouse Brain(2021-04-12) KARAMAHMUTOĞLU, TUĞBA; Frantz D., ERYİĞİT KARAMAHMUTOĞLU T., kirik d., Berrocal E.Publication Metadata only EFFECTS OF KINDLING STIMULATIONS ON PARVALBUMIN IMMUNOREACTIVITY IN SUBSTANTIA NIGRA PARS RETICULATA OF GAERS AND WISTAR RATS(2014-07-03) GÜLÇEBİ İDRİZ OĞLU, MEDİNE; KARAMAHMUTOĞLU, TUĞBA; ONAT, FİLİZ; AKMAN Ö., GÜLÇEBİ İDRİZ OĞLU M., KARAMAHMUTOĞLU T., ONAT F.