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    Antiamnesic effects of tofisopam against scopolamine-induced cognitive impairments in rats
    (Pergamon-Elsevier Science Ltd, 2020) Ucel, Umut Irfan; Can, Ozgur Devrim; Ozkay, Umide Demir; Ulupinar, Emel
    In this study, we investigated the potential therapeutic effects of tofisopam, a 2,3-benzodiazepine derivative anxiolytic, on cognitive deficits in rats with scopolamine-induced amnesia. Cognitive performance of the rats was investigated by using the Morris water maze and passive avoidance tests. Changes in motor activity were assessed by using the activity cage and Rota-rod tests and then morphological changes in the hippocampus were assessed via immunohistochemical stainings. The results indicated that scopolamine impaired learning and memory parameters in rats. Worsened cognitive performance, neuronal loss, and decreased hippocampal synaptophysin, Ki-67, and glial fibrillary acidic protein density were observed. Tofisopam administration at a dose of 50 mg/kg for seven days improved the impaired cognitive performance, enhanced the attenuated synaptic transmission in the hippocampus, increased proliferation in subgranular zones, and improved the decrease in astrocytes in amnesic rats. These findings point out the anti-amnesic effects of tofisopam with concomitant improvements in the hippocampal synaptogenesis, neurogenesis, and glial plasticity, for the first time. Presented beneficial effects of tofisopam on cognitive dysfunctions may have a notable clinical value considering the fact that one of the most important side effects of 1,4-benzodiazepines, which are classical anxiolytic drugs, is amnesia. However, these preclinical results need to be confirmed with further clinical studies, first.
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    Catecholaminergic and Cholinergic Systems Mediate Beneficial Effect of Vortioxetine on Diabetes-Induced Neuropathic Pain
    (Mdpi, 2023) Turan Yucel, Nazli; Kandemir, Ummuhan; Ucel, Umut Irfan; Ozkay, Umide Demir; Can, Ozgur Devrim
    The therapeutic potential of vortioxetine on mechanical hyperalgesia/allodynia was investigated in rats with streptozotocin-induced diabetes, and its possible mechanism of action was elucidated in this study. The obtained findings demonstrated that subacute vortioxetine treatment (5 and 10 mg/kg for 2 weeks) increased the reduced paw-withdrawal thresholds of diabetic rats both in the Randall-Selitto and Dynamic plantar tests. Moreover, the falling latencies of animals did not change in the Rota-rod assessments. These results suggest that vortioxetine administration significantly improved diabetes-induced hyperalgesia and allodynia responses in the rats without affecting their motor coordination. The vortioxetine (5 mg/kg)-induced antihyperalgesic and antiallodynic effects were reversed by AMPT, yohimbine, ICI 118,551, sulpiride and atropine pre-treatments, suggesting the involvement of the catecholaminergic system, alpha(2)- and beta(2)-adrenoceptors, D-2/3 dopaminergic receptors and cholinergic muscarinic receptors in the exhibited pharmacological activity, respectively. Moreover, the data from the immunohistochemical studies indicated that the inhibition of c-Fos overexpression in dorsal horn neurons also mediates the beneficial effect of this drug. Vortioxetine induced no difference in plasma glucose levels in diabetic rats. If clinical studies confirm these findings, the concomitant beneficial effect of vortioxetine on mood disorders and its neutral activity profile on glycemic control may make it an alternative drug for the treatment of neuropathic pain.
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    Effect of Reboxetine Treatment on BDNF, Synaptophysin, and PSD-95 Levels in the Spinal Dorsal Horn of Rats with Diabetic Neuropathy
    (Marmara Univ, Inst Health Sciences, 2023) Yucel, Nazli Turan; Ucel, Umut Irfan; Ozkay, Umide Demir; Ulupinar, Emel; Can, Ozgur Devrim
    Objective: It is known that neuropathic pain is accompanied by alterations in the levels of neurotrophic factors and synaptic proteins in the microenvironment of the spinal dorsal horn. Such changes contribute to hyperalgesia and allodynia processes; thus, analgesic drugs can exert their pharmacological effects by affecting the expressions, levels, or functions of these endogenous substances. In this study, based on the knowledge that reboxetine (a selective noradrenaline reuptake inhibitor) has the potential for antihyperalgesic efficacy in diabetic neuropathy, we aimed to examine the probable effects of this drug on diabetes-induced changes in brain-derived neurotrophic factor (BDNF), synaptophysin (the pre-synaptic marker of synaptic integration), and postsynaptic density-95 (PSD-95) (the postsynaptic marker of synaptic integration) levels in the superficial laminae of the dorsal horn.Methods: Experimental diabetes was induced by a single-dose injection of streptozotocin (STZ) (50 mg/kg) in rats. After four week-long induction period of painful diabetic neuropathy, rats were treated orally with 8 mg/kg reboxetine for two weeks. Hyperalgesia responses were evaluated by using the Randall-Selitto and Hargreave's tests. Following the pain tests, immunohistochemical studies were performed.Results: Two weeks of reboxetine administration increased the reduced paw withdrawal thresholds and shortened the paw withdrawal latencies of diabetic rats in neuropathic pain tests, indicating the antihyperalgesic efficacy of this drug. Moreover, augmented BDNF and synaptophysin levels in diabetic rats reversed by reboxetine treatment. However, there was no alteration in the densities of PSD-95, in both STZ-diabetic and reboxetine-treated STZ-diabetic rats.Conclusion: The obtained results suggested that inhibition of central sensitization and modulation of spinal plasticity seem to be pharmacological mechanisms underlying reboxetine's antihyperalgesic effects on diabetic rats. However, further studies are still needed to clarify the exact mechanism of action.
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    Subacute ivermectin-induced affective dysregulation: Evidence for hippocampal microglial and astrocytic activation
    (Elsevier Sci Ltd, 2026) Eser, Mustafa; Yazic, Cevsen; Kandemir, Ummuhan; Ucel, Umut Irfan; Bozkurt, Mehmet Fatih; Ozkay, Umide Demir; Can, Ozgur Devrim
    Ivermectin (IVR) is a semi-synthetic macrocyclic lactone widely used against nematodes. Under physiological conditions, its central nervous system (CNS) penetration is limited by P-glycoprotein-mediated efflux at the blood-brain barrier (BBB). Nevertheless, supratherapeutic dosing, BBB-compromising pathologies, concomitant P-glycoprotein inhibitors, or MDR1 variants can enhance CNS entry and precipitate neurotoxicity. To evaluate behavioural and neuroinflammatory sequelae of subacute exposure, rats received IVR (1, 5, or 10 mg/kg; i.p.) once daily for 21 days. Animals were assessed for motor function (activity cage, Rota-rod), affective behaviour (elevated plus maze, modified forced swim test), and cognition (Morris water maze). Assay validation employed diazepam (1 and 3 mg/kg; i.p.), desipramine (30 mg/kg; i.p.), and piracetam (200 mg/kg; i.p.), administered according to their respective protocols. IVR did not alter motor performance or spatial learning and memory across doses. However, 5 and 10 mg/kg reduced the percentage of open-arm entries and increased immobility, consistent with anxiety-and depression-like phenotypes, respectively. At 10 mg/kg, hippocampal immunohistochemistry revealed increased Iba1 and GFAP immunoreactivity within CA1, indicating microglial and astrocytic activation. Quantitative counts demonstrated no significant change in CA1 neuronal number across treatment groups, implying that the observed glial activation occurred in the absence of detectable neuronal loss. Collectively, our data indicate that subacute, high-dose IVR provokes affective behavioural alterations coupled to hippocampal neuroinflammation, while sparing gross motor function and measurable cognitive performance under the present conditions. These findings underscore caution when administering IVR at elevated doses or in settings that compromise BBB integrity and warrant further mechanistic and time-resolved investigation.