Browsing by Author "Yavuz, Melis"

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Dexmedetomidine, an alpha 2A receptor agonist, triggers seizures unilaterally in GAERS during the pre-epileptic phase: does the onset of spike-and-wave discharges occur in a focal manner?
(Frontiers, 2023-12-11) Yavuz, Melis; İyiköşker, Pelin; Mutlu, Nursima; Kılıçparlar, Serra; Şalcı, Öykü Hazal; Dolu, Gökçen; Kaymakçılar, Elif Nur; Akkol, Serdar; Onat, Filiz
Introduction: The genetic absence epilepsy rat from Strasbourg (GAERS) is a rat model for infantile absence epilepsy with spike-and-wave discharges (SWDs). This study aimed to investigate the potential of alpha 2A agonism to induce seizures during the pre-epileptic period in GAERS rats. Methods: Stereotaxic surgery was performed on male pups and adult GAERS rats to implant recording electrodes in the frontoparietal cortices (right/left) under anesthesia (PN23–26). Following the recovery period, pup GAERS rats were subjected to electroencephalography (EEG) recordings for 2 h. Before the injections, pup epileptiform activity was examined using baseline EEG data. Dexmedetomidine was acutely administered at 0.6 mg/kg to pup GAERS rats 2–3 days after the surgery and once during the post-natal (PN) days 25–29. Epileptiform activities before injections triggered unilateral SWDs and induced sleep durations, and power spectral density was evaluated based on EEG traces. Results: The most prominent finding of this study is that unilateral SWD-like activities were induced in 47% of the animals with the intraperitoneal dexmedetomidine injection. The baseline EEGs of pup GAERS rats had no SWDs as expected since they are in the pre-epileptic period but showed low-amplitude non-rhythmic epileptiform activity. There was no di􀀀erence in the duration of epileptiform activities between the basal EEG groups and DEX-injected unilateral SWD-like-exhibiting and non-SWD-like activities groups; however, the sleep duration of the unilateral SWD-like-exhibiting group was shorter. Power spectrum density (PSD) results revealed that the 1.75-Hz power in the left hemisphere peaks significantly higher than in the right. Discussion: As anticipated, pup GAERS rats in the pre-epileptic stage showed no SWDs. Nevertheless, they exhibited sporadic epileptiform activities. Specifically, dexmedetomidine induced SWD-like activities solely within the left hemisphere. These observations imply that absence seizures might originate unilaterally in the left cortex due to a2AAR agonism. Additional research is necessary to explore the precise cortical focal point of this activity.
Investigation of Neurogenesis in Kindled Wistar and Genetic Absence Epilepsy Rats
(MARMARA UNIV, INST HEALTH SCIENCES, 2022-01-01) Kandemir, Cansu; Yavuz, Melis; Karakaya, Fatma Bedia; Kaya, Ozlem Tugce Cilingir; Onat, Filiz; Sirvanci, Serap
Objective: The most common type of epilepsy affecting about 50 million people worldwide is temporal lobe epilepsy (TLE). Chemical and electrical kindling methods in animals can be used to form TLE model. In the present study, it was aimed to investigate neurogenesis in the hippocampus of adult kindled Wistar rats and genetic absence epilepsy rats from Strasbourg (GAERS) rats by immunofluorescence methods.Methods: Adult Wistar and GAERS albino rats weighing 250-300 gr were injected pentylenetetrazole (PTZ) (35 mg/kg, s.c.) every other day to produce chemical kindling. Animals having 5 times grade 5 seizures were considered to be kindled. Intracardiac perfusion was performed under deep anesthesia on the 7th and 14th days after the last grade 5 seizure. Immunofluorescence methods were used to demonstrate newly formed neurons, astroglial cells, and mature neurons, by using anti-doublecortin (DCX), anti-glial fibrillary acidic protein (GFAP), and antineuronal nuclear antigen (NeuN) primary antibodies, respectively. Sections were then examined under a fluorescence microscope.Results: DCX (+) cells were found to be increased in GAERS control groups compared to the Wistar control groups