Person: GÖREN, MEHMET ZAFER
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GÖREN
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MEHMET ZAFER
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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 Metadata only Contribution of M-1 and M-2 muscarinic receptor subtypes to convulsions in fasted mice treated with scopolamine and given food(ELSEVIER SCIENCE BV, 2019) AYDIN OMAY, BANU; Bacanak, Merve Saygi; Aydin, Banu; Cabadak, Hulya; Nurten, Asiye; Goren, Mehmet Zafer; Enginar, NurhanTreatment of fasted mice and rats with the nonselective muscarinic antagonist, scopolamine or atropine, causes convulsions after food intake. This study evaluated the effect of fasting on the expression of M-1 and M-2 muscarinic receptors in the brain regions, the relationship between receptor expression and seizure stages, and the muscarinic receptor subtype which plays a role in the occurrence of convulsions. Mice were grouped as allowed to eat ad lib (fed) and deprived of food for 24 h (fasted). Fasted animals developed convulsions after being treated with scopolamine (60%) or the selective M-1 receptor antagonist pirenzepine (10 mg/kg; 20% and 60 mg/kg; 70%) and given food. Fasting increased expression of M-1 receptors in the frontal cortex and M-2 receptors in the hippocampus, but produced no change in the expression of both receptors in the amygdaloid complex. Food intake after fasting decreased M-1 receptor expression in the frontal cortex and M-1 and M-2 receptor expression in the hippocampus. Seizure severity was uncorrelated with muscarinic receptor expression in the brain regions. Taken together, these findings provide evidence for the role of M-1 muscarinic receptor antagonism and fasting-induced increases in M-1 and M-2 expression possible underlying mechanism in the occurrence of convulsions in fasted animals.Publication Metadata only Muscarinic receptor-mediated nitric oxide release in a K562 erythroleukaemia cell line(2009) AYDIN OMAY, BANU; Cabadak H., Küçükibrahimoǧlu E., Aydin B., Kan B., Gören M.Z.1 In the present study we have investigated the expression of muscarinic receptors in K562 erythroleukaemic cells and the effects of muscarinic agonist and antagonists on extracellular citrulline levels in these cells, as a marker of nitric oxide (NO) generation. 2 Muscarinic acetylcholine receptors (M 1-M5) play key roles in regulating many diverse physiological processes. Recent studies suggest that muscarinic receptors mediate some cellular events in haematopoietic cells. Multiple subtypes of muscarinic receptors are expressed in different human cells. NO, a free radical and a signaling molecule, is involved in the regulation of many physiological functions and derived from certain nitric oxide synthases (NOS), which are related to muscarinic receptors. 3 In this study, the presence of M2, M3 and M4 subtypes in K562, an erythroleukaemic cell line, was demonstrated by using the reverse transcriptase-polymerase chain reaction. Moreover, the generation of NO induced by carbachol, a non-selective muscarinic agonist, was investigated by using high-performance liquid chromatography to measure changes in extracellular l-citrulline levels. 4 We found that carbachol enhanced l-citrulline production in K562 erythroleukaemic cells. The effect of carbachol on l-citrulline production was antagonized by atropine and 4-diphenylacetoxy-N-methylpiperidine (4-DAMP), while tropicamide had little effect. These results suggest that the muscarinic receptor M 3 subtype may mediate NO signaling in K562 erythroleukaemic cells. © 2009 Blackwell Publishing Ltd.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 Metadata only Increased Noradrenaline Levels in the Rostral Pons can be Reversed by M1 Antagonist in a Rat Model of Post-traumatic Stress Disorder(SPRINGER/PLENUM PUBLISHERS, 2013) AYDIN OMAY, BANU; Terzioglu, Berna; Kaleli, Melisa; Aydin, Banu; Ketenci, Sema; Cabadak, Hulya; Goren, M. ZaferThe dysregulation of hypothalamic-pituitary-adrenal axis and noradrenergic, serotonergic and glutamatergic systems are thought to be involved in the pathophysiology of post-traumatic stress disorder. The effect of selective M1 muscarinic receptor antagonist, pirenzepine on anxiety indices was investigated by using elevated plus maze, following exposure to trauma reminder. Upon receiving the approval of ethics committee, Sprague-Dawley rats were exposed to dirty cat litter (trauma) for 10 min and 1 week later, the rats confronted to a trauma reminder (clean litter). The rats also received intraperitoneal pirenzepine (1 or 2 mg/kg/day) or saline for 8 days. Noradrenaline (NA) concentration in the rostral pons was analyzed by HPLC with electrochemical detection. The anxiety indices of the rats subjected to the trauma reminder were increased when compared to control rats (p < 0.05). Pirenzepine treatment in traumatized rats displayed similar anxiety indices of non-traumatized rats treated with physiological saline. Although freezing time was prolonged with pirenzepine in traumatized groups the change was not found statistically significant. The NA level was 1.5 +/- A 0.1 pg/mg in non-traumatized rats and increased to 2.4 +/- A 0.2 pg/mg in traumatized rats. Bonferroni post hoc test revealed that the NA content of the rostral pons of the traumatized rats treated with physiological saline was significantly higher than the content of other groups (p < 0.01). We conclude that NA content in the rostral pons increases in respect to confrontation to a trauma reminder which can be reversed by M1 antagonist pirenzepine indicating the roles of M1 receptors.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 Metadata only The change in muscarinic receptor subtypes in different brain regions of rats treated with fluoxetine or propranolol in a model of post-traumatic stress disorder(ELSEVIER SCIENCE BV, 2012) AYDIN OMAY, BANU; Aykac, Asli; Aydin, Banu; Cabadak, Hulya; Goren, M. ZaferThis study shows the possible contribution of muscarinic receptors in the pathophysiology of post-traumatic stress disorder. Sprague-Dawley rats of both sexes were exposed to dirty cat litter (trauma) for 10 min and the protocol was repeated 1 week later with a trauma reminder (clean litter). The rats also received intraperitoneal fluoxetine (2.5, 5 or 10 mg/kg/day), propranolol (10 mg/kg/day) or saline for 7 days between two exposure sessions. Functional behavioral experiments were performed using elevated plus maze, following exposure to trauma reminder. Western blot analyses for M-1, M-2, M-3, M-4 and M-5 receptor proteins were employed in the homogenates of the hippocampus, the frontal cortex and the amygdaloid complex. The anxiety indices increased from 0.63 +/- 0.02 to 0.89 +/- 0.04 in rats exposed to the trauma reminder. The freezing times were also recorded as 47 +/- 6 and 133 +/- 12 s, in control and test animals respectively. Fluoxetine or propranolol treatments restored the increases in the anxiety indices and the freezing times. Female rats had higher anxiety indices compared to males. Western blot data showed increases in M-2 and M-5 expression in the frontal cortex. Expression of M-1 receptors increased and M-4 subtype decreased in the hippocampus. In the amygdaloid complex of rats, we also detected a down-regulation of M-4 receptors. Fluoxetine and propranolol only corrected the changes occurred in the frontal cortex. These results may imply that muscarinic receptors are involved in this experimental model of post-traumatic stress disorder. (C) 2012 Elsevier B.V. All rights reserved.Publication Metadata only Investigation of the Roles of Non-neuronal Acetylcholine in Chronic Myeloid Leukemic Cells and their Erythroid or Megakaryocytic Differentiated Lines(BENTHAM SCIENCE PUBL LTD, 2018) AYDIN OMAY, BANU; Aydin, Banu; Cabadak, Hulya; Goren, M. ZaferBackground: Many studies suggested that Acetylcholine (ACh) might serve as an autocrine/paraerine growth factor in several types of tumors or tumor cell lines. High levels of Acetylcholinesterase (AChE) activity have been reported in primary brain tumors, ovarian, colon and lung tumors. Objectives: The role of cholinergic signaling needs to be clarified in in leukemia. Method: K562 cells were derived from a chronic myelogenous leukemia patient during blast crisis serving as pluripotent hematopoietic stein cells. K562 cells were incubated with various cholinergic agonists or antagonists to investigate the role of ACh in different differentiated cell lines. Results: Our experiments showed that AChE activity was increased in response to ACh in undifferentiated K562 cells, but in the erythroid differentiated K562 cells a high concentration of ACh (1 mM) decreased the AChE activity. ACh failed to elevate the AChE activity in the megakaryocytic differentiated K562 cells. An AChE inhibitor, eserine, also suppressed the AChE activity in a concentration-dependent manner. Choline uptake inhibition by hemicholinium did increase the AChE activity but not in the erythroid differentiated K562 DOS cell line. Likewise, megakaryocytic differentiated K562 cells also displayed a similar pattern. Vesamicole, a vesicular choline uptake inhibitor, produced similar results. Curare, a nicotinic antagonist, elevated the cell counts of the megakaryocytic differentiated cells. Conclusion: Our findings may suggest excess extracellular ACh will decrease the cell growth in undifferentiated and megakaryocytic differentiated K562 cell lines through nicotinic type cholinoceptors.Publication Metadata only Cross-Talk of Cholinergic and ?-Adrenergic Receptor Signalling in Chronic Myeloid Leukemia K562 Cells(2022) AYDIN OMAY, BANU; Aydın, Banu; Gören, Mehmet Zafer; Kanlı, Zehra; Cabadak, Hülya