Person: GÜLHAN, REZZAN
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GÜLHAN
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REZZAN
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Publication Metadata only Wistar ve genetik absans epilepsili (GAERS) sıçanlarda dendrit morfolojisinin incelenmesi(2021-11-21) YAZI, SEVDENUR; ŞEHİRLİ, ÜMİT SÜLEYMAN; GÜLHAN, REZZAN; KİRAZLI, ÖZLEM; Yazı S., Şehirli Ü. S., Gülhan R., Onat F., Kirazlı Ö.Publication Metadata only Evaluation of dendrite morphology in wistar and genetic absence epileptic (GAERS) rats(2022-07-09) ŞEHİRLİ, ÜMİT SÜLEYMAN; KİRAZLI, ÖZLEM; GÜLHAN, REZZAN; YAZI S., ŞEHİRLİ Ü. S., GÜLHAN R., ONAT F., KİRAZLI Ö.Aims The aim of the study is to examine the morphological features of dendrites and dendritic spines of pyramidal neurons in somatosensory cortex and hippocampus of Wistar and GAERS (Genetic Absence Epilepsy Rat from Strasbourg) rats. Methods GAERS (n=5) and Wistar (n=5) rats were sacrificed by transcardial perfusion method. Brain tissues were stained using the FD Rapid GolgiStain Kit. Coronal sections of 200 µm thickness were obtained with cryostat. Pyramidal neurons in deep layers of the somatosensory cortex and CA1 region of the hippocampus were examined using light microscope and Neurolucida 360 software. Branching and length of apical dendrite and basal dendrites, and types and densities of dendritic spines were analyzed. Results Statistically the total number of dendrite nodes (p=0.0053, p=0,0047), the total number of dendrite segments (dendritic arborization) (p=0.0036, p=0,0036), the total number of dendrite terminations (p=0.0033, p=0,0029), the total dendrite length (µm) (p=0.0002, p=0,0007) and the dendritic spine density (1/µm) (p=0.0168, p=0,0120) of the somatosensory cortex and the hippocampus were significantly higher in GAERS rats, respectively. When dendritic spine types were evaluated separately, stubby type dendritic spines in the hippocampus were found to be significantly higher in GAERS rats compared to Wistar rats (p=0.0204). Conclusions It was concluded that intense synaptic activation seen in postsynaptic cells in the somatosensory cortex and hippocampus in GAERS causes changes in the dendrite morphology of pyramidal neurons. This study was supported by Marmara University Scientifical Research Projects Commission (TYL-2021-10244).Publication Metadata only The neuroprotective effect of regular swimming exercise programme on the dopaminergic neurons localized in the striatum of Parkinsonian rat models(2016-09-05) BORACI, HATİCE; KİRAZLI, ÖZLEM; GÜLHAN, REZZAN; YILDIZ, SERCAN DOĞUKAN; ŞEHİRLİ, ÜMİT SÜLEYMAN; BORACI H., KİRAZLI Ö., GÜLHAN R., YILDIZ S. D., ŞEHİRLİ Ü. S.Publication Metadata only Genetik absans epilepsili ve epileptik olmayan sıçanlarda nigrostriatal yolak dejenerasyonunun kalretinin immunoreaktivitesi üzerine etkisi(2022-11-10) KİRAZLI, ÖZLEM; GÜLÇEBİ İDRİZ OĞLU, MEDİNE; ŞEHİRLİ, ÜMİT SÜLEYMAN; GÜLHAN, REZZAN; KİRAZLI Ö., Turgan Aşık Z. N., Çulpan Y., GÜLÇEBİ İDRİZ OĞLU M., ŞEHİRLİ Ü. S., GÜLHAN R., ONAT F.Amaç: Kalsiyum bağlayıcı proteinler, nöronal işlev ve nörogenezde önemli rol oynamaktadır. Kalretinin, dikensiz GABAerjik internöronlarda eksprese edilmekte ve gelen dopaminerjik afferentlerle ve glutamaterjik kortikostriatal afferentlerle sinaptik bağlantı kurmaktadır. Yaşla birlikte azalabilen kalretinin, ileri yaşlardaki motor fonksiyonda oluşacak kayıplardan sorumlu tutulabilmektedir. Parkinson modeli sıçanlarda nigro -striatal yolaktaki dopaminerjik nöron kaybı sonrasında striatumda bulunan kalretinin pozitif internöronlarda azalma meydana geldiği gösterilmiştir. Bu azalışa glutamat reseptörlerindeki aşırı aktivite ve dopaminin eksikliğinin neden olduğu iddia edilmiştir. Kalretinin pozitif internöronların temporal epilepsiye karşı hassas olduğu gösterilmiştir. Epileptogenez sürecinde kimyasal lezyon ile nigro-striatal yolağın devre dışı bırakılmasının kalretinin sentezleyen nöronlar üzerine etkisi incelenmiştir. Gereç ve Yöntem: Striatum, Substantia Nigra pars compacta ve pars reticulata da bulunan kalretinin içeren nöronların tespiti için medial ön beyin demetine 6-OHDA uygulanan Wistar (n=5) GAERS (n=5) Wistar kontrol (n=5) ve GAERS kontrol (n=5) 40µm’lik sıçan beyin kesitlerine immohistokimya yöntemi uygulanmıştır. Nöronların sayım işlemleri floresans boyanmış kesitler üzerinden yapılmıştır. İstatistiksel değerlendirme için GraphPad Prism Tek yönlü ANOVA ve gruplar arasındaki karşılaştırma kullanılmıştır. Bulgular: Çalışmamızda (6 –OHDA) enjekte edilen Wistar ve GAERS sıçanlarda kontrol gruplarına göre kalretinin pozitif hücre sayısında azalma gözlenmiştir. Bu azalma Striatum için istatistiksel olarak anlamlı bulunmazken, Substantia Nigra pars compacta (p<0,05) ve pars reticulata (p<0,05) için anlamlıdır. Sonuç: Literatürde (6 –OHDA) enjekte edilen sıçanlarda nigrostriatal yolakta sağlam kalan dopaminerjik nöronların kalretinin eksprese ettiği gözlemlenmiştir. Bu sonuçlar sonrasında, kalretininin nöroprotektif etkisinden dolayı dopaminerjik nöronları koruyabildiği ileri sürülebilir.Publication Metadata only GABA(A) receptor mediated transmission in the thalamic reticular nucleus of rats with genetic absence epilepsy shows regional differences: Functional implications(ELSEVIER SCIENCE BV, 2006) ONAT, FİLİZ; Aker, Rezzan Gulhan; Ozyurt, Hazan B.; Yananli, Hasan R.; Cakmak, Yusuf Ozgur; Ozkaynakci, Aydan E.; Sehirli, Umit; Saka, Erdinc; Cavdar, Safiye; Onat, Filiz YimazThe aim of the present study was to investigate the effect of local injections of the GABA(A) receptor antagonist, bicuculline, into the rostral and caudal parts of the thalamic reticular nucleus (TRN), on the generation of spike-and-wave discharges in Genetic Absence Epilepsy Rats from Strasbourg (GAERS). Spike-and-wave discharges are important in the pathophysiology of absence epilepsy and generated by the cortico-thalamo-cortical pathway, where GABA has a significant role, particularly in the TRN. Artificial cerebrospinal fluid or bicuculline was administered to rostral or caudal parts of TRN of GAERS through a stereotaxically placed guide cannula. Administration of bicuculline produced opposite effects according to the injection site. Administration into the caudal TRN produced statistically significant increases in the duration of spike-and-wave discharges, whereas injections into the rostral TRN produced significant decreases. Correspondingly, distinct patterns of afferent connections have been demonstrated with the wheat-germ-agglutinin horseradish peroxidase (WGA-HRP) retrograde tracing method in control non-epileptic rats and GAERS for the rostral and caudal parts of the TRN. Injection of WGA-HRP tracer showed no detectable difference regarding the rostral and caudal connections between GAERS and Wistar animals. Rostral parts of TRN have thalamic and cortical connections that are primarily motor and limbic whereas for the caudal parts these connections are primarily sensory. Further, the rostral parts receive inputs from the substantia nigra pars reticularis and the ventral pallidum that the caudal part lacks. The extent to which these connectional differences may be responsible for the functional differences demonstrated by the bicucculine injections remains to be explored. (c) 2006 Elsevier B.V. All rights reserved.Publication Metadata only Evaluation of dendrite morphology in wistar andgenetic absence epileptic (GAERS) rats(2022-08-30) ŞEHİRLİ, ÜMİT SÜLEYMAN; KİRAZLI, ÖZLEM; GÜLHAN, REZZAN; YAZI S., ŞEHİRLİ Ü. S., GÜLHAN R., ONAT F., KİRAZLI Ö.Publication Metadata only Connections of the dorsomedial hypothalamic nucleus from the forebrain structures in the rat(KARGER, 2002) ONAT, FİLİZ; Onat, FY; Aker, R; Sehirli, U; San, T; Cavdar, SThe dorsomedial hypothalamic nucleus (DMH) has been implicated as an area controlling autonomic activity. The aim of this study was to demonstrate connections of the anterior and posterior DMH to the forebrain structures, using a horseradish peroxidase (HRP) retrograde axonal transport technique in rats. The results of HRP labelling show that the anterior and posterior DMH indicate a number of differences in their connections. The posterior DMH has intense connections with the cortex (cingulate, frontal, parietal and insular), amygdala (lateral and basolateral) and hippocampus (CA1 and CA2), whereas the anterior DMH has faint connections with the cortex (cingulate, frontal and parietal) and prominent connections with the septal and bed nucleus of stria terminalis. These differences in connections of the DMH may provide sites for the specific autonomic function integrated by the DMH. Copyright (C) 2002 S. Karger AG, Basel.Publication Metadata only Neuroprotective effect of regular swimming exercise on calretinin-positive striatal neurons of Parkinsonian rats(SPRINGER, 2020) BORACI, HATİCE; Boraci, H.; Kirazli, O.; Gulhan, R.; Sercan, D. Yildiz; Sehirli, U. S.In Parkinson's disease (PD), physical therapy is one of the mainstays of supportive treatment modalities. This study focused on the neuroprotective effect of regular exercise on striatal calretinin positive interneurons in a rat model of PD. 6-hydroxydopamine (6-OHDA) was injected unilaterally into the medial forebrain bundle of Wistar rats. 6-OHDA lesioned (Parkinsonian) and unlesioned (control) rats were divided into sedentary and exercise groups. Exercise groups had daily swimming sessions for 30 min for 6 weeks. After 6-OHDA injections, an apomorphine-induced rotation test was performed (0.05 mg/kg, subcutaneous) at the 3rd and 6th weeks. At the end of the 6th week, brains were removed following transcardiac perfusion. The brain sections were stained immunohistochemically for tyrosine hydroxylase and calretinin reactivity. The number of rotations was significantly lower in Parkinsonian exercise group compared to Parkinsonian sedentary group at the 6th week (p = 0.024) and there was significant difference between Parkisonian sedentary groups at the 3rd and 6th weeks (p < 0.002). The calretinin positive interneurons significantly increased in the Parkinsonian exercise group compared to Parkinsonian sedentary group (p = 0.0003) and control exercise group (p < 0.0001). To conclude, the swimming exercise led to a striking increment of calretinin positive interneurons in the striatum of Parkinsonian rat. These findings indicated that the neuroprotective mechanism of exercise increased the number of striatal calretinin positive interneurons that might generate new approaches for the mechanism of neuroprotection. We concluded that striatal calretinin positive interneurons have an important role in the neuroprotective mechanisms of exercise in PD.