Person: GÖREN, MEHMET ZAFER
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
GÖREN
First Name
MEHMET ZAFER
Name
10 results
Search Results
Now showing 1 - 10 of 10
Publication Open Access The effects of partial bilateral lesioning of substantia nigra in a genetic absence epilepsy rat model(2002-04-01) GÜLHAN, REZZAN; ONAT, FİLİZ; GÖREN, MEHMET ZAFER; GÖREN M. Z., GÜLHAN R., ONAT F., Ergün A.Objective: \"Genetic Absence Epilepsy Rats from Strasbourg\" (GAERS), an inbred Wistar strain, serve as an experimental venue. These rats generate spontaneous spike-and-wave discharges (SWD) and have increased γ-aminobutyric acid (GABA) levels in the ventrolateral thalamus (VLT). Recently, substantia nigra pars reticulata (SNpr) was reported to act as an endogeneous inhibitory mechanism in the generation, onset and maintenance of various types of seizures. The presence of tonic control exerted by SNpr in absence seizures should also be tested in GAERS. Methods: In this current study, GABA and L-glutamic acid release in VLT of GAERS with partial bilateral electrolytic lesions of SNpr was evaluated by using microdialysis technique with fluorescent detection. Results: GABA levels in VLT were 0.12±0.04 μM and 0.24±0.08 μM in sham-lesioned and SNpr-lesioned GAERS, respectively. L-glutamic acid level was found to be 0.41 5±0.150 μM in sham-lesioned group and 0.324±0.094 μM in SNpr-lesioned GAERS. Statistical analysis revealed no significant difference between sham-lesioned and SNpr-lesioned rats. The number and the duration of SWD were also similar in two groups. Conclusion: These findings show that SNpr does not exert a tonic control in GAERS and we assume that intact SNpr acts as a site that may exert an inhibition on target structures when activated in GAERS.Publication Open Access The α2C-adrenoceptor antagonist JP-1302 controls behavioral parameters, tyrosine hydroxylase activity and receptor expression in a rat model of ketamine-induced schizophrenia-like deficits(2022-11-01) AKAKIN, DİLEK; GÖREN, MEHMET ZAFER; Tekin N., Karamahmutoğlu T. E. , Aykaç A., AKAKIN D., GÖREN M. Z.© 2022Schizophrenia is a chronic disabling disease affecting 1 % of the population. Current antipsychotics have limited efficacy in mitigating the severity of the symptoms of the disease. Therefore, searching for new therapeutic targets is essential. Previous studies have shown that α2C-adrenoceptor antagonists may have antipsychotic and pro-cognitive effects. Therefore, the current study evaluates the behavioral and neurochemical effects of JP-1302, a selective α2C-adrenoceptor antagonist, in a model of schizophrenia-like deficits induced by sub-chronic ketamine (KET) administration. Here, we administered ketamine (25 mg/kg, i.p.) to male and female Wistar rats for eight consecutive days. On the last two days of ketamine administration, rats were pretreated with either JP-1302 (1-3-10 μmol/kg, i.p.), chlorpromazine (0.1 mg/kg, i.p.), or saline, and the behavioral tests were performed. Behaviors related to positive (locomotor activity), negative (social interaction), and cognitive (novel object recognition) symptoms of schizophrenia were assessed. Glutamate, glutamine, GABA levels, and α2C-adrenoceptor expression were measured in the frontal cortex and the hippocampus. Tyrosine hydroxylase immunocytochemical reactivity was also shown in the midbrain regions. Sub-chronic ketamine administration increased locomotor activity and produced robust social interaction and object recognition deficits, and JP-1302 significantly ameliorated ketamine-induced cognitive deficits. Ketamine induced a hyperdopaminergic activity in the striatum, which was reversed by the treatment with JP-1302. Also, the α2C-adrenoceptor expression was higher in the frontal cortex and hippocampus in the ketamine-treated rats. Our findings confirm that α2C-adrenoceptor antagonism may be a potential drug target for treating cognitive disorders related to schizophrenia.Publication Open Access Plasma concentration-time profile of a single dose of enteric-coated omeprazole in male and female healthy volunteers(2000-01-01) GÖREN, MEHMET ZAFER; AKIN, ŞEHNAZ; GÜLHAN, REZZAN; ONAT, FİLİZ; Iskender E., ASLAN N., GÖREN M. Z., Tellioglu T., Akin S., Erin N., GÜLHAN R., ONAT F., Berkman K., Oktay S.O b je c tiv e : T h e b io a vaila b ility of a single dose (20 m g) o f tw o e n te ric -c o a te d o m e p ra z o le fo rm u la tio n s, m arketed in T urkey, given 10-15 m in b e fo re b reakfast, w as studied in 12 healthy vo lu n te e rs (6 m ales and 6 fem ales) in a d o u b le blind, cro s s o v e r design. M e th o d s : B lood sam ples w ere collected prior to and at 10 tim e points w ithin 12 hrs. after dosing. P la s m a o m e p ra z o le c o n c e n tra tio n s w e re m easured by H P LC te ch n iq u e in our laboratory. R e s u lts a n d C o n c lu s io n s : T he tw o products w ere found to be b io e q u iva le n t in term s of extent of a b s o rp tio n (th e a re a u n d e r the p la s m a c o n c e n tra tio n -tim e cu rve s). M u ltip e a k p la sm a co n ce n tra tio n pro file s w e re seen in m ost of the su b je cts w ith both products. T im e to the e a rlie r peaks w as 1-2 hrs. and those peaks w ere low er in a m p litu d e th a n th e p e a ks re a ch e d a p p ro x im a te ly 4 .5 hrs. a fte r the a p p lica tio n . In te re stin g ly, the m u ltip e a k profile w as m ore fre q u e n t and the e a rlie r peaks w ere sig nificantly higher in fe m a le su b je cts than in m ales. The reason fo r th is g e n d e r d iffe re n ce in m ultipeak p la s m a c o n c e n tra tio n - tim e p ro file of oral o m e p ra zo le needs fu rth e r investigation.Publication Open Access The behavioral and neurochemical effects of methylprednisolone or metyrapone in a post-traumatic stress disorder rat model(KARE PUBL, 2019) AYDIN OMAY, BANU; Tanriverdi, Ayse Melek; Aydin, Banu; Bebitoglu, Berna Terzioglu; Cabadak, Hulya; Goren, M. ZaferOBJECTIVE: Mechanisms contributing to the post-traumatic stress disorder (PTSD) that involve several physiological sys- tems, and the activation of the hypothalamic-pituitary-adrenal axis (HPA) is one of the most known systems in the PTSD pathophysiology. The present study investigates the potential effects of methylprednisolone, metyrapone and their association with the noradrenergic system within the rostral pons, a region containing the locus coeruleus (LC) in a rat model of PTSD induced with predator scent. METHODS: In this study, Sprague-Dawley rats were exposed to the stress by exposure to the scent of dirty cat litter, which is a natural stressor of a predator. One week later, the rats were re-exposed to a situational reminder (clean cat litter). The rats were treated using either methylprednisolone, metyrapone or physiological saline before exposure to a situational reminder (n=8 in each group). Noradrenaline (NA) levels in the rostral pons homogenates were analysed using ELISA. RESULTS: The anxiety indices of the rats exposed to the trauma were found to be significantly higher than the anxiety indices of the control rats. Metyrapone produced a significant increase in the anxiety indices of the non-stressed rats, and methylprednisolone did not produce a change in the anxiety indices of the non-stressed rats. Methylprednisolone treatment suppressed the anxiety in the stressed rats. Metyrapone treatment increased the anxiety indices in the stressed rats but still being lower than that of the saline-treated stressed rats. Significant decrease in the freezing time was observed following the methylprednisolone treatment both in the stressed and non-stressed rats. NA content in the rostral pons of the stressed rats was significantly higher than that of the non-stressed rats. Methylprednisolone or metyrapone treatments decreased the NA content in the non-stressed rats as compared to the saline treatment. However, these decreases were not significant. CONCLUSION: In this study, findings suggest that stress may give rise to endocrine, autonomic and behavioural responses. The anxiety indices and NA levels in the rostral pons increased with the traumatic event. The methylprednisolone treatment may suppress anxiety through interactions between the LC and the HPA axis.Publication Open Access Blood pressure and heart rate in aripiprazole once – monthly and paliperidone 1 and 3-month long-acting preparations(2023-05-31) GÖREN, MEHMET ZAFER; Saridogan G. E., GÖREN M. Z.Objective: This study aims to evaluate the blood pressure and heart rates of the patients treated with aripiprazole once-monthly, paliperidone 1-month, and paliperidone 3-month long-acting injections. Patients and Methods: This study was a non-invasive observational study. Subjects using the same long-acting injection preparation for at least four months without skipped injections were assigned to 3 groups according to their treatments. They were screened starting from routine injection day and monthly for four months. Heart rate, systolic blood pressure, and diastolic blood pressure were recorded for each subject. Results: Systolic and diastolic blood pressure among the three treatment groups demonstrated no statistical significance. The heart rate of the paliperidone 3-month group was significantly higher than the aripiprazole once-monthly group. However, the mean heart rate was within the physiological limits. Thus, a clinical significance can hardly be attributed. Conclusion: Aripiprazole once-monthly, paliperidone 1-month, and paliperidone 3-month long-acting injections are non-inferior regarding heart rate, systolic and diastolic blood pressure during the maintenance treatment. Keywords: Long-acting antipsychotic, Hypertension tachycardia, Schizophrenia, Maintenance treatmentPublication Open Access Investigation into the role of the cholinergic system in radiation-induced damage in the rat liver and ileum(OXFORD UNIV PRESS, 2014-09-01) ERCAN, FERİHA; Ozyurt, Hazan; Ozden, A. Sevgi; Cevik, Ozge; Ozgen, Zerrin; Cadirci, Selin; Elmas, Merve Acikel; Ercan, Feriha; Sener, Goksel; Goren, M. Z.It has been previously shown that acetylcholine (ACh) may affect pro-inflammatory and anti-inflammatory cytokines. The role of the cholinergic system in radiation-induced inflammatory responses and tissue damage remains unclear. Therefore, the present study was designed to determine the radio-protective properties of the cholinergic system in the ileum and the liver of rats. Rats were exposed to 8-Gy single-fraction whole-abdominal irradiation and were then decapitated at either 36 h or 10 d post-irradiation. The rats were treated either with intraperitoneal physiological saline (1 ml/kg), physostigmine (80 mu g/kg) or atropine (50 mu g/kg) twice daily for 36 h or 10 d. Cardiac blood samples and liver and ileal tissues were obtained in which TNF-alpha, IL-1 beta and IL-10 levels were assayed using ELISA. In the liver and ileal homogenates, caspase-3 immunoblots were performed and myeloperoxidase (MPO) activity was analyzed. Plasma levels of IL-1 beta and TNF-alpha increased significantly following radiation (P < 0.01 and P < 0.001, respectively) as compared with non-irradiated controls, and physostigmine treatment prevented the increase in the pro-inflammatory cytokines (P < 0.01 and P < 0.001, respectively). Plasma IL-10 levels were not found to be significantly changed following radiation, whereas physostigmine augmented IL-10 levels during the late phase (P < 0.01). In the liver and ileum homogenates, IL-1 beta and TNF-alpha levels were also elevated following radiation, and this effect was inhibited by physostigmine treatment but not by atropine. Similarly, physostigmine also reversed the changes in MPO activity and in the caspase-3 levels in the liver and ileum. Histological examination revealed related changes. Physostigmine experiments suggested that ACh has a radio-protective effect not involving the muscarinic receptors.Publication Open Access The Neurochemical Effects of Prazosin Treatment on Fear Circuitry in a Rat Traumatic Stress Model(KOREAN COLL NEUROPSYCHOPHARMACOLOGY, 2020-05-31) AYDIN OMAY, BANU; Ketenci, Sema; Acet, Nazife Gokce; Saridogan, Gokce Elif; Aydin, Banu; Cabadak, Hulya; Goren, Mehmet ZaferObjective: The timing of administration of pharmacologic agents is crucial in traumatic stress since they can either potentiate the original fear memory or may cause fear extinction depending on the phase of fear conditioning. Brain noradrenergic system has a role in fear conditioning. Data regarding the role of prazosin in traumatic stress are controversial. Methods: In this study, we examined the effects of prazosin and the noradrenergic system in fear conditioning in a predator stress rat model. We evaluated the direct or indirect effects of stress and prazosin on noradrenaline (NA), gamma-aminobuytyric acid (GABA), glutamate, glycine levels and choline esterase activity in the amygdaloid complex, the dorsal hippocampus, the prefrontal cortex and the rostral pons. Results: Our results demonstrated that prazosin might alleviate defensive behaviors and traumatic stress symptoms when given during the traumatic cue presentation in the stressed rats. However prazosin administration resulted in higher anxiety levels in non stressed rats when the neutral cue was presented. Conclusion: Prazosin should be used in PTSD with caution because prazosin might exacerbate anxiety in non-traumatized subjects. However prazosin might as well alleviate stress responses very effectively. Stress induced changes included increased NA and GABA levels in the amygdaloid complex in our study, attributing noradrenaline a possible inhibitory role on fear acquisition. Acetylcholine also has a role in memory modulation in the brain. We also demonstrated increased choline esterase acitivity. Cholinergic modulation might be another target for indirect prazosin action which needs to be further studied.Publication Open Access The role of Glu N1 activated nitric oxide synthase in rat model of post traumatic stress disorder(2016-01-01) AYDIN OMAY, BANU; CABADAK, HÜLYA; GÖREN, MEHMET ZAFER; ayhan B. G., AYKAÇ A., gür k., AYDIN B., Seçgin E., Seven İ., CABADAK H., GÖREN M. Z.Objectives: Activation of neuronal nitric oxide synthase (nNOS) and interrelated alterations of calmodulin and ionotropic glutamate receptor (GluN1) levels are unknown in post traumatic stress disorder (PTSD). Materials and Methods: Sprague-Dawley rats of both sexes were exposed to to dirty cat litter, and then placed on an elevated plus maze. An anxiety index was calculated and tissue samples from hippocampus and amygdala were prepered in order to to detect calmodulin, NOS and GluN1 by immunoblotting. Results: The anxiety indices of the traumatized rats were markedly higher than those of the controls (p<0.05). GluN1 and calmodulin levels were decreased in the dorsal hippocampus and amygdaloid complex of the traumatized rats. NOS expression increased significantly in both the amygdaloid complex and dorsal hippocampus where the increase was statistically more prominent in the amygdaloid complex (p< 0.001) than in the dorsal hippocampus of the traumatized rats (p<0.05). Conclusion: Predator exposure in rats causes long-lasting anxiogenic effects associated with increases in NOS and decreases in GluN1 expressions in brain areas related to PTSD symptoms and excitotoxicity. The results suggest that excitotoxicity occurs through other mechanisms rather than GluN1 receptors. Keywords: Predator scent test, nNOS, Glutamate, Calmodulin, Amygdala, HippocampusPublication Open Access Evaluation of the pregnant women's approaches regarding drug utilization(KARE PUBL, 2020) AKICI, AHMET; Tamirci, Mevhibe; Aydin, Volkan; Soyalan, Mertdogan; Akici, Narin; Goren, Mehmet Zafer; Akici, AhmetOBJECTIVE: Drug utilization habits of the pregnant are a critical aspect of rational use of the medicine (RUM). This study aimed to analyze the RUM related attitudes and the behaviors of women during their pregnancies. METHODS: The data were collected between May 2016-October 2016 by conducting surveys to 71 pregnant women admitted to the private and governmental hospitals in five districts of Northern Cyprus. The sociodemographic characteristics of the pregnant as well as their attitudes and behaviors concerning drug use were evaluated. RESULTS: The mean age and the gestational week of the patients was 29.7 +/- 4.3 years and 25.7 +/- 11.2 weeks, respectively. Planned pregnancies constituted 71.8% of all. The percentage of patients with an unplanned pregnancies who were using drugs at the time of the survey (25.0%) was lower than that in those with planned pregnancies (49.0%, p<0.05). Almost two-thirds (66.2%) of the women were exposed to a drug during pregnancy, mostly for vitamin/mineral prophylaxis (38.3%) and agents controlling nausea/vomiting (19.1%). Two out of eleven women (18.2%) were using folic acid when they learned about their pregnancy. One of the drugs used for the chronic disorder in the third trimester was acetylsalicylic acid (11.1%), a category D drug in this setting. Most of the patients stated that they frequently read the instructions (60.9%), often paying attention to side effects (56.5%). Considering some of the habits related to drug use, 8.7% and 10.9% of pregnant women declared that they sometimes did not follow the instructions and dosage/duration of the drug usage, respectively. Seven patients (15.2%) declared that they did not consider side effects on the medication guide while more than half (56.5%) did it often. Near one in five (19.6%) of the pregnant women stated that they hesitated about the drug usage due to teratogenicity risks. CONCLUSION: Our study highlights the drug utilization attitudes and behaviors of pregnant women during pregnancy in Northern Cyprus, indicating several shortcomings, including insufficient prenatal folic acid use, occasional use of risky drugs, and unsatisfactory medication guide handling. Available findings underline the necessity of education not only for patients but also for healthcare providers to disseminate RUM in pregnancy.Publication Open Access Evaluation of the knowledge, attitude, and behaviors of physicians and pharmacists regarding the use of medicines in pregnancy(MARMARA UNIV, 2021) AKICI, AHMET; Tamirci, Mevhibe; Akici, Ahmet; Aydin, Volkan; Sakarya, Sibel; Goren, Mehmet ZaferPregnancy is a critical aspect of rational use of medicine (RUM) and imposes important responsibilities on the parties. This study aimed to analyze the knowledge, attitudes, and behaviors of the physicians and pharmacists regarding pharmacotherapy in pregnancy. The data were collected between April 2016-July 2017 by questionnaires and analyses of the prescriptions in Northern Cyprus. Simulated prescriptions (n=50) for pregnant women (PW) were applied at pharmacies, and pharmacists' (n=95) and obstetricians' (n=30) attitudes were evaluated through surveys. In addition, PW prescriptions (n=122) were collected from pharmacies and evaluated. All data were re-obtained after one year. The mean number of drugs per PW prescription was 1.48 +/- 0.73. In teratogenicity risk evaluation, 6.6% of medicines were in D/X and 16.7% were in C categories. The ratio of these three categories medicines in scripts was about eight times higher than which was considered as teratogenic based on physicians' opinions. Serious shortcomings were found in writing the format information in prescriptions. In simulated prescription analysis, mean dispensing time was 3.3 +/- 2.3 min. Almost half of the pharmacists were observed to give the drug requested by simulated PW without any confirmation of the prescription. The dispensing performances of the pharmacists were mainly different than their related statements on the survey. Our study highlighted the deficiencies in physicians' and pharmacists' RUM knowledge, attitudes, and behaviors in pregnancy, where the gaps seem unchanged after one year. These findings underline necessity of education and counselling service interventions for healthcare providers to disseminate RUM in pregnancy.