33 results on '"Kortenska L"'
Search Results
2. P.164 Automatic detection of neuronal activity in baseline and seizure-evoked conditions by extracellular microelectrode recording and computer processing in rats
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Tchekalarova, J., primary, Kortenska, L., additional, Boynov, K., additional, and Marinov, P., additional
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- 2020
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3. P.494 Agomelatine corrects impaired sleep-wake rhythmicity through restoration of per 1 circadian rhythm expression of rats exposed to chronic constant light
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Ivanova, N., primary, Marinov, P., additional, Atanasova, M., additional, Kortenska, L., additional, and Tchekalarova, J., additional
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- 2019
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4. P.2.30 Agomelatine restores home cage activity and sleep/wake disturbances in a model of melatonin deficiency
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Ivanova, N., primary, Marinov, P., additional, Kortenska, L., additional, and Tchekalarova, J., additional
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- 2019
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5. Pharmacological activation of metabotropic glutamate receptor subtype 4 is protective against focal transient ischemia
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Bernabucci, M., Mastroiacovo, F., Moyanova, S., Kortenska, L., Mitreva, R., Ngomba, R. T., Battaglia, Giuseppe, Bruno, Valeria Maria Gloria, and Nicoletti, Ferdinando
- Published
- 2009
6. ENDOTHELIN-1-INDUCED CEREBRAL ISCHEMIA: EFFECTS OF KETANSERIN AND MK-801 ON LIMB PLACING IN RATS
- Author
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MOYANOVA, S., primary, KORTENSKA, L., additional, and MITREVA, R., additional
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- 2007
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7. Quantitative Electroencephalographic Changes Due To Middle Cerebral Artery Occlusion By Endothelin 1 In Conscious Rats
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Moyanova, S., primary, Kortenska, L., additional, Kirov, R., additional, and Iliev, I., additional
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- 1998
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8. Quantitative Electroencephalographic Changes Due To Middle CerebralArtery Occlusion By Endothelin 1 In Conscious Rats.
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Moyanova, S., Kortenska, L., Kirov, R., and Iliev, I.
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VASOCONSTRICTORS , *ENDOTHELINS , *CEREBRAL circulation , *CEREBRAL arteries , *THERAPEUTICS - Abstract
The powerful vasoconstrictor peptide endothelin-1 (ET1) has been shownto reduce local cerebral blood flow in brain areas supplied by the middlecerebral artery (MCA) to a pathologically low level upon intracerebral injectionadjacent to the MCA. This reduction manifests itself as an ischemic infarct,that is fully developed within 3 days after ET1 injection. The aim of thepresent study is to examine the effect of ET1 on electroencephalographic (EEG)activity. ET1 was microinjected unilaterally at a dose of 60 pmol in 3 µlof saline to the MCA in conscious rats. EEG signals were recorded from thefrontoparietal cortical area, supplied by MCA, from the first up to the fourteenthday after ET1 injection. EEG activity was analyzed by the fast Fourier transformation.A significant shift to a lower EEG frequency, i.e., augmentation of slow wavesand a reduction of alpha-like and faster EEG waves was found post-ET1. Thiseffect was maximal after 3–7 days when the most severe destruction ofneurons in this cortical area occurs, as has been previously demonstrated.The results suggest that the quantitative EEG analysis may provide usefuladditional information about the functional disturbances associated with focalcerebral ischemia. [ABSTRACT FROM AUTHOR]
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- 1998
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9. High-voltage electroencephalogram spindles in rats, aging and 5-HT~2 antagonism
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Moyanova, S., Kortenska, L., and Kirov, R.
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- 1998
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10. Ketanserin reduces the postischemic EEG and behavioural changes following Endothelin-1-induced occlusion of the middle cerebral artery in conscious rats
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Moyanova Slavianka, Kortenska Lidia, Kirov Roumen, Itzev Dimitar, and Usunoff Kamen
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cerebral ischemia ,eeg ,endothelin-1 ,ketanserin ,neurological assessment ,conscious rat ,Medicine - Published
- 2008
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11. Effects of pinealectomy on anxiety and depressive-like behaviour in Wistar rats
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Nenchovska, Z., Kortenska, L., Stefanova, M., Alova, L., Atanasova, M., and Jana Tchekalarova
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pinealectomy ,depression ,anxiety ,serotonin - Abstract
In the present study, we aimed to investigate the influence of endogenous melatonin abolishment via pinea lectomyone motional behaviour associated with anxiety and depressive responses in male Wistar rats. Sham-operated (sham) or pinealectomised (Pin) rats were tested in the hole-board (HB) test, elevated plus maze (EPM), sucrose preference test (SCT) and forced swimming test (FST) one month (Ist trial) and three months (IInd trial) after surgery. Melatonin deficit caused a significant decrease of the head-dipping at the holes accompanied by increased time of stereotype grooming both during the Ist and the IInd trial. Pinealectomy elevated both the number of entries and the time spent on the open arms in EPM test and this effect was significant a month after the removal of the pineal gland. Sucrose preference was decreased in Pin rats compared to sham rats during the light phase in both the Ist and the IInd trial, respectively. The immobility time tested in FS was significantly increased a month after pinealectomy. The observed depressive behaviour in Pin rats was accompanied by a tendency of decreased 5-HT release from the hippocampus. Taken together, a model of melatonin deficit caused an impulsiveand depressive-like behaviour, which was evident three months after pinealectomy. Our results suggest that endogenous melatonin synthetized in the pineal gland affects these behavioural responses through a regulatory mechanism on the hippocampal 5-HT release.
12. Age-dependence of sensorimotor and cerebral electroencephalographic asymmetry in rats subjected to unilateral cerebrovascular stroke
- Author
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Moyanova, S. G., Mitreva, R. G., Kortenska, L. V., Nicoletti, F., Ngomba, R.T., Moyanova, S. G., Mitreva, R. G., Kortenska, L. V., Nicoletti, F., and Ngomba, R.T.
- Abstract
Background: The human population mostly affected by stroke is more than 65Â years old. This study was designed to meet the recommendation that models of cerebral ischemia in aged animals are more relevant to the clinical setting than young animal models. Until now the majority of the pre-clinical studies examining age effects on stroke outcomes have used rats of old age. Considering the increasing incidence of stroke among younger than old human population, new translational approaches in animal models are needed to match the rejuvenation of stroke. A better knowledge of alterations in stroke outcomes in middle-aged rats has important preventive and management implications providing clues for future investigations on effects of various neuroprotective and neurorestorative drugs against cerebrovascular accidents that may occur before late senescence. Methods: We evaluated the impact of transient focal ischemia, induced by intracerebral unilateral infusion of endothelin-1 (Et-1) near the middle cerebral artery of conscious rats, on volume of brain damage and asymmetry in behavioral and electroencephalographic (EEG) output measures in middle-aged (11-12Â month-old) rats. Results: We did not find any age-dependent difference in the volume of ischemic brain damage three days after Et-1 infusion. However, age was an important determinant of neurological and EEG outcomes after stroke. Middle-aged ischemic rats had more impaired somatosensory functions of the contralateral part of the body than young ischemic rats and thus, had greater left-right reflex/sensorimotor asymmetry. Interhemispheric EEG asymmetry was more evident in middle-aged than in young ischemic rats, and this could tentatively explain the behavioral asymmetry.Conclusions: With a multiparametric approach, we have validated the endothelin model of ischemia in middle-aged rats. The results provide clues for future studies on mechanisms underlying plasticity after brain damage and motivate investigations of nov
13. Age-dependence of sensorimotor and cerebral electroencephalographic asymmetry in rats subjected to unilateral cerebrovascular stroke
- Author
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Moyanova, S. G., Mitreva, R. G., Kortenska, L. V., Nicoletti, F., Ngomba, R.T., Moyanova, S. G., Mitreva, R. G., Kortenska, L. V., Nicoletti, F., and Ngomba, R.T.
- Abstract
Background: The human population mostly affected by stroke is more than 65Â years old. This study was designed to meet the recommendation that models of cerebral ischemia in aged animals are more relevant to the clinical setting than young animal models. Until now the majority of the pre-clinical studies examining age effects on stroke outcomes have used rats of old age. Considering the increasing incidence of stroke among younger than old human population, new translational approaches in animal models are needed to match the rejuvenation of stroke. A better knowledge of alterations in stroke outcomes in middle-aged rats has important preventive and management implications providing clues for future investigations on effects of various neuroprotective and neurorestorative drugs against cerebrovascular accidents that may occur before late senescence. Methods: We evaluated the impact of transient focal ischemia, induced by intracerebral unilateral infusion of endothelin-1 (Et-1) near the middle cerebral artery of conscious rats, on volume of brain damage and asymmetry in behavioral and electroencephalographic (EEG) output measures in middle-aged (11-12Â month-old) rats. Results: We did not find any age-dependent difference in the volume of ischemic brain damage three days after Et-1 infusion. However, age was an important determinant of neurological and EEG outcomes after stroke. Middle-aged ischemic rats had more impaired somatosensory functions of the contralateral part of the body than young ischemic rats and thus, had greater left-right reflex/sensorimotor asymmetry. Interhemispheric EEG asymmetry was more evident in middle-aged than in young ischemic rats, and this could tentatively explain the behavioral asymmetry.Conclusions: With a multiparametric approach, we have validated the endothelin model of ischemia in middle-aged rats. The results provide clues for future studies on mechanisms underlying plasticity after brain damage and motivate investigations of nov
14. Protective role for type 4 metabotropic glutamate receptors against ischemic brain damage
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Moyanova, S. G., Mastroiacovo, F., Kortenska, L. V., Mitreva, R. G., Fardone, E., Santolini, I., Sobrado, M., Battaglia, G., Bruno, V., Nicoletti, F., Ngomba, R. T., Moyanova, S. G., Mastroiacovo, F., Kortenska, L. V., Mitreva, R. G., Fardone, E., Santolini, I., Sobrado, M., Battaglia, G., Bruno, V., Nicoletti, F., and Ngomba, R. T.
- Abstract
We examined the influence of type 4 metabotropic glutamate (mGlu4) receptors on ischemic brain damage using the permanent middle cerebral artery occlusion (MCAO) model in mice and the endothelin-1 (Et-1) model of transient focal ischemia in rats. Mice lacking mGlu4 receptors showed a 25 to 30 increase in infarct volume after MCAO as compared with wild-type littermates. In normal mice, systemic injection of the selective mGlu4 receptor enhancer, N-phenyl-7-(hydroxyimino)cyclopropabchromen-1a-caboxamide (PHCCC; 10 mg/kg, subcutaneous, administered once 30 minutes before MCAO), reduced the extent of ischemic brain damage by 35 to 45. The drug was inactive in mGlu4 receptor knockout mice. In the Et-1 model, PHCCC administered only once 20 minutes after ischemia reduced the infarct volume to a larger extent in the caudate/putamen than in the cerebral cortex. Ischemic rats treated with PHCCC showed a faster recovery of neuronal function, as shown by electrocorticographic recording and by a battery of specific tests, which assess sensorimotor deficits. These data indicate that activation of mGlu4 receptors limit the development of brain damage after permanent or transient focal ischemia. These findings are promising because selective mGlu4 receptor enhancers are under clinical development for the treatment of Parkinson's disease and other central nervous system disorders. © 2011 ISCBFM All rights reserved.
15. Melatonin Supplementation Alleviates Impaired Spatial Memory by Influencing Aβ 1-42 Metabolism via γ-Secretase in the icvAβ 1-42 Rat Model with Pinealectomy.
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Georgieva I, Tchekalarova J, Nenchovska Z, Kortenska L, and Tzoneva R
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- Animals, Rats, Male, Memory Disorders drug therapy, Memory Disorders metabolism, Memory Disorders etiology, Maze Learning drug effects, Melatonin pharmacology, Melatonin metabolism, Amyloid beta-Peptides metabolism, Amyloid Precursor Protein Secretases metabolism, Spatial Memory drug effects, Disease Models, Animal, Peptide Fragments metabolism, Alzheimer Disease metabolism, Alzheimer Disease drug therapy, Pinealectomy, Hippocampus metabolism, Hippocampus drug effects
- Abstract
In the search for Alzheimer's disease (AD) therapies, most animal models focus on familial AD, which accounts for a small fraction of cases. The majority of AD cases arise from stress factors, such as oxidative stress, leading to neurological changes (sporadic AD). Early in AD progression, dysfunction in γ-secretase causes the formation of insoluble Aβ
1-42 peptides, which aggregate into senile plaques, triggering neurodegeneration, cognitive decline, and circadian rhythm disturbances. To better model sporadic AD, we used a new AD rat model induced by intracerebroventricular administration of Aβ1-42 oligomers (icvAβ1-42 ) combined with melatonin deficiency via pinealectomy (pin). We validated this model by assessing spatial memory using the radial arm maze test and measuring Aβ1-42 and γ-secretase levels in the frontal cortex and hippocampus with ELISA. The icvAβ1-42 + pin model experienced impaired spatial memory and increased Aβ1-42 and γ-secretase levels in the frontal cortex and hippocampus, effects not seen with either icvAβ1-42 or the pin alone. Chronic melatonin treatment reversed memory deficits and reduced Aβ1-42 and γ-secretase levels in both structures. Our findings suggest that our icvAβ1-42 + pin model is extremely valuable for future AD research.- Published
- 2024
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16. Predatory Odor Exposure as a Potential Paradigm for Studying Emotional Modulation of Memory Consolidation-The Role of the Noradrenergic Transmission in the Basolateral Amygdala.
- Author
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Peshev B, Ivanova P, Krushovlieva D, Kortenska L, Atanasova D, Rashev P, Lazarov N, and Tchekalarova J
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- Animals, Male, Rats, Cyclic AMP Response Element-Binding Protein metabolism, Propranolol pharmacology, Memory Consolidation physiology, Memory Consolidation drug effects, Basolateral Nuclear Complex metabolism, Basolateral Nuclear Complex physiology, Basolateral Nuclear Complex drug effects, Odorants, Norepinephrine metabolism, Hippocampus metabolism, Hippocampus physiology, Hippocampus drug effects, Emotions physiology, Emotions drug effects, Rats, Wistar
- Abstract
The pivotal role of the basolateral amygdala (BLA) in the emotional modulation of hippocampal plasticity and memory consolidation is well-established. Specifically, multiple studies have demonstrated that the activation of the noradrenergic (NA) system within the BLA governs these modulatory effects. However, most current evidence has been obtained by direct infusion of synthetic NA or beta-adrenergic agonists. In the present study, we aimed to investigate the effect of endogenous NA release in the BLA, induced by a natural aversive stimulus (coyote urine), on memory consolidation for a low-arousing, hippocampal-dependent task. Our experiments combined a weak object location task (OLT) version with subsequent mild predator odor exposure (POE). To investigate the role of endogenous NA in the BLA in memory modulation, a subset of the animals (Wistar rats) was treated with the non-selective beta-blocker propranolol at the end of the behavioral procedures. Hippocampal tissue was collected 90 min after drug infusion or after the OLT test, which was performed 24 h later. We used the obtained samples to estimate the levels of phosphorylated CREB (pCREB) and activity-regulated cytoskeleton-associated protein (Arc)-two molecular markers of experience-dependent changes in neuronal activity. The result suggests that POE has the potential to become a valuable behavioral paradigm for studying the interaction between BLA and the hippocampus in memory prioritization and selectivity.
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- 2024
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17. Protective Effect of the Novel Melatonin Analogue Containing Donepezil Fragment on Memory Impairment via MT/ERK/CREB Signaling in the Hippocampus in a Rat Model of Pinealectomy and Subsequent Aβ 1-42 Infusion.
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Tchekalarova J, Ivanova P, Krushovlieva D, Kortenska L, and Angelova VT
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- Rats, Animals, Donepezil pharmacology, Pinealectomy, Hippocampus metabolism, Amyloid beta-Peptides metabolism, Memory Disorders drug therapy, Memory Disorders etiology, Melatonin pharmacology, Melatonin therapeutic use, Alzheimer Disease drug therapy, Peptide Fragments
- Abstract
A reduction in melatonin function contributes to the acceleration of Alzheimer's disease (AD), and understanding the molecular processes of melatonin-related signaling is critical for intervention in AD progression. Recently, we synthesized a series of melatonin analogues with donepezil fragments and tested them in silico and in vitro. In this study, one of the most potent compounds, 3c , was evaluated in a rat model of pinealectomy (pin) followed by icvAβ
1-42 infusion. Melatonin was used as the reference drug. Treatment with melatonin and 3c (10 mg/kg, i.p. for 14 days) had a beneficial effect on memory decline and the concomitant increase in hippocampal Aβ1-42 and pTAU in the pin+icvAβ1-42 rats. Melatonin supplementation facilitated non-amyloidogenic signaling via non-receptor (histone deacetylase sirtuin 1, SIRT1) and receptor-related signaling (MT/ERK/CREB). The hybrid 3c analogue up-regulated the MT1A and MT2B receptors, pERK and pCREB. Our results strongly support the hypothesis that melatonin-related analogues may become a promising drug candidate for Alzheimer's disease therapy.- Published
- 2024
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18. Spontaneously hypertensive rats vs. Wistar Kyoto and Wistar rats: An assessment of anxiety, motor activity, memory performance, and seizure susceptibility.
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Tchekalarova J, Krushovlieva D, Ivanova P, and Kortenska L
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- Rats, Animals, Rats, Inbred SHR, Rats, Inbred WKY, Rats, Wistar, Anxiety psychology, Cognition, Seizures chemically induced, Motor Activity, Disease Models, Animal, Brain-Derived Neurotrophic Factor, Attention Deficit Disorder with Hyperactivity metabolism, Attention Deficit Disorder with Hyperactivity psychology
- Abstract
Spontaneously hypertensive rats (SHRs) are widely accepted for modeling essential hypertension and Attention deficit hyperactivity disorder (ADHD). However, data concerning central nervous system changes associated with behavioral responses of this strain and usage of Wistar Kyoto (WKY) rats as controls are confounding. The objective of the present study was to assess the impact of anxiety and motor activity on the cognitive responses of SHRs compared to Wistar and WKY rats. In addition, the role of brain-derived neurotrophic factor (BDNF) in the hippocampus on cognitive behavior and seizure susceptibility in the three strains was evaluated. In Experiment#1, SHR demonstrated impulsive responses in the novelty suppression feeding test accompanied by impaired spatial working and associative memory in the Y maze and object recognition test compared with the Wistar rat but not WKY rats. In addition, the WKY rats exhibited diminished activity compared to Wistar rats in an actimeter. In Experiment#2, the seizure susceptibility was assessed by 3-min electroencephalographic (EEG) recording after two consecutive injections of pentylenetetrazol (PTZ) (20+40 mg/kg). The WKY rats were more vulnerable to rhythmic metrazol activity (RMA) than the Wistar rats. In contrast, Wistar rats were more prone to generalized tonic-clonic seizures (GTCS) than WKY rats and SHRs. Control SHR had lower BDNF expression in the hippocampus compared to Wistar rats. However, while the BDNF levels were elevated in the Wistar and WKY rats after PTZ injection, no change in this signaling molecule was observed in the SHR in the seizure condition. The results suggest Wistar rats as a more appropriate control of SHR than WKY rats for studying memory responses mediated by BDNF in the hippocampus. The higher vulnerability to seizures in Wistar and WKY rats compared to SHR might be linked to PTZ-induced decreased expression of BDNF in the hippocampus., Competing Interests: Declaration of Competing Interest I declare no conflict of interest., (Copyright © 2023 Institute of Neurobiology Bulgarian Academy of Sciences. Published by Elsevier Inc. All rights reserved.)
- Published
- 2023
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19. Sex-Dependent Effects of Piromelatine Treatment on Sleep-Wake Cycle and Sleep Structure of Prenatally Stressed Rats.
- Author
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Tchekalarova J, Kortenska L, Marinov P, and Ivanova N
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- Animals, Circadian Rhythm physiology, Electroencephalography, Female, Indoles, Male, Pregnancy, Pyrans pharmacology, Rats, Receptors, Melatonin, Sleep physiology, Brain-Derived Neurotrophic Factor pharmacology, Melatonin pharmacology, Melatonin therapeutic use
- Abstract
Prenatal stress (PNS) impairs the circadian rhythm of the sleep/wake cycle. The melatonin (MT) analogue Piromelatine (Pir) was designed for the treatment of insomnia. The present study aimed to explore effects of Pir on circadian rhythmicity, motor activity, and sleep structure in male and female rats with a history of prenatal stress (PNS). In addition, we elucidated the role of MT receptors and brain-derived neurotrophic factor (BDNF) to ascertain the underlying mechanism of the drug. Pregnant rats were exposed to different stressors from day seven until birth. Piromelatine (20 mg/kg/day/14 days) was administered to young adult offspring. Home-cage locomotion, electroencephalographic (EEG) and electromyographic (EMG) recordings were conducted for 24 h. Offspring treated with vehicle showed sex-and phase-dependent disturbed circadian rhythm of motor activity and sleep/wake cycle accompanied by elevated rapid eye movement (REM) pattern and theta power and diminished non-rapid eye movement (NREM) sleep and delta power. While Pir corrected the PNS-induced impaired sleep patterns, the MT receptor antagonist luzindol suppressed its effects in male and female offspring. In addition, Pir increased the BDNF expression in the hippocampus in male and female offspring with PNS. Our findings suggest that the beneficial effect of Pir on PNS-induced impairment of sleep/wake cycle circadian rhythm and sleep structure is exerted via activation of MT receptors and enhanced BDNF expression in the hippocampus in male and female offspring.
- Published
- 2022
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20. Impact of Melatonin Deficit on Emotional Status and Oxidative Stress-Induced Changes in Sphingomyelin and Cholesterol Level in Young Adult, Mature, and Aged Rats.
- Author
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Tchekalarova J, Nenchovska Z, Kortenska L, Uzunova V, Georgieva I, and Tzoneva R
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- Animals, Emotions, Oxidative Stress, Rats, Sphingomyelins, Melatonin pharmacology, Pineal Gland physiology, Pineal Gland surgery
- Abstract
The pineal gland regulates the aging process via the hormone melatonin. The present report aims to evaluate the effect of pinealectomy (pin) on behavioral and oxidative stress-induced alterations in cholesterol and sphingomyelin (SM) levels in young adult, mature and aging rats. Sham and pin rats aged 3, 14 and 18 months were tested in behavioral tests for motor activity, anxiety, and depression. The ELISA test explored oxidative stress parameters and SM in the hippocampus, while total cholesterol was measured in serum via a commercial autoanalyzer. Mature and aged sham rats showed low motor activity and increased anxiety compared to the youngest rats. Pinealectomy affected emotional responses, induced depressive-like behavior, and elevated cholesterol levels in the youngest rats. However, removal of the pineal gland enhanced oxidative stress by diminishing antioxidant capacity and increasing the MDA level, and decreased SM level in the hippocampus of 14-month-old rats. Our findings suggest that young adult rats are vulnerable to emotional disturbance and changes in cholesterol levels resulting from melatonin deficiency. In contrast, mature rats with pinealectomy are exposed to an oxidative stress-induced decrease in SM levels in the hippocampus.
- Published
- 2022
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21. Chronic agomelatine treatment alleviates icvAβ-induced anxiety and depressive-like behavior through affecting Aβ metabolism in the hippocampus in a rat model of Alzheimer's disease.
- Author
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Ilieva K, Atanasova M, Atanasova D, Kortenska L, and Tchekalarova J
- Subjects
- Acetamides, Amyloid Precursor Protein Secretases metabolism, Amyloid beta-Peptides metabolism, Animals, Anxiety, Disease Models, Animal, Hippocampus metabolism, Rats, Alzheimer Disease chemically induced, Alzheimer Disease complications, Alzheimer Disease drug therapy
- Abstract
Recently, we reported that the atypical antidepressant agomelatine (Ago) exerted a beneficial impact on behavioral changes and concomitant neuropathological events in icvSTZ rat model of sporadic Alzheimer diseases (AD). In the present study, we aimed to explore the effect of Ago (40 mg/kg, i.p. for 30 days) on beta-amyloid (Aβ) metabolism in icvAβ
1-42 rat model of AD. The melatonin analogue was administered either simultaneously with Aβ1-42 (AβAgo1) or 30 days later during the late stage of the progression of AD (AβAgo2). Treatment with Ago in the early stage of AD attenuated anxiety and depressive-like responses but was inefficient against Aβ-induced impairment of hippocampus-dependent spatial memory. The melatonin analogue, administered both during the early and the late stage of AD, corrected to control level the elevated Aβ1-42 in the frontal cortex (FC) and the hippocampus. The concentration of α-secretase was enhanced by AβAgo1 compared to the sham- and Aβ-veh groups in the hippocampus. No changes in the concentration of β-secretase in the FC and the hippocampus as well as of γ-secretase in the FC were observed among groups. Both the AβAgo1 and AβAgo2 attenuated to control level the Aβ-induced increased concentration of γ-secretase in the hippocampus. AβAgo1 exerted also structure-specific neuroprotection observed mainly in the CA1, septal CA3b subfield of the dorsal hippocampus and septo-temporal piriform cortex (Pir) and partially in the temporal CA3c, septal and temporal Pir. These findings suggest that Ago treatment in the early stage of AD can exert beneficial effects on concomitant behavioral impairments and neuroprotection in associated brain structures. The antidepressant administration both in the early stage and after the progression of AD affected Aβ metabolism via decreasing of γ-secretase concentration in the hippocampus., (Copyright © 2021 Elsevier Inc. All rights reserved.)- Published
- 2021
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22. Agomelatine treatment corrects impaired sleep-wake cycle and sleep architecture and increases MT 1 receptor as well as BDNF expression in the hippocampus during the subjective light phase of rats exposed to chronic constant light.
- Author
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Tchekalarova J, Kortenska L, Ivanova N, Atanasova M, and Marinov P
- Subjects
- Acetamides pharmacology, Animals, Antidepressive Agents pharmacology, Antidepressive Agents therapeutic use, Brain-Derived Neurotrophic Factor genetics, Circadian Rhythm drug effects, Circadian Rhythm physiology, Electroencephalography drug effects, Electroencephalography methods, Gene Expression, Hippocampus drug effects, Hypnotics and Sedatives pharmacology, Hypnotics and Sedatives therapeutic use, Male, Photic Stimulation adverse effects, Rats, Rats, Wistar, Receptor, Melatonin, MT1 genetics, Sleep Stages drug effects, Sleep Wake Disorders drug therapy, Acetamides therapeutic use, Brain-Derived Neurotrophic Factor biosynthesis, Hippocampus metabolism, Receptor, Melatonin, MT1 biosynthesis, Sleep Stages physiology, Sleep Wake Disorders metabolism
- Abstract
Rationale: Exposure to chronic constant light (CCL) has a detrimental impact on circadian rhythms of motor activity and sleep/wake cycles. Agomelatine is an atypical antidepressant showing a chronotropic activity., Objectives: In this study, we explored the role of melatonin (MT) receptors and brain-derived neurotrophic factor (BDNF) in the brain in the mechanism underlying the effects of agomelatine on diurnal variations of motor activity, sleep/wake cycle, and sleep architecture in a rat model of CCL., Methods: In Experiment #1, home cage activity was monitored automatically with cameras for a period of 24 h. The diurnal rhythm of MT
1, MT2 receptors, and BDNF expression in the hippocampus and frontal cortex (FC), was tested using the ELISA test. In Experiment #2, rats were equipped with electroencephalographic (EEG) and electromyographic (EMG) electrodes and recordings were made under basal conditions (12:12 LD cycle + vehicle), LL + vehicle and LL + agomelatine (40 mg/kg/day for 21 days)., Results: The rats exposed to CCL showed an impaired diurnal rhythm of motor activity and sleep/wake cycle with reduced NREM sleep and delta power and increased REM sleep and theta power. The duration and number of episodes of the wake were diminished during the subjective dark phase in this group. The circadian rhythm of MT1 and MT2 receptors and their expression did not change in the hippocampus and FC under CCL exposure, while the BDNF levels in the hippocampus decreased during the subjective light phase. Agomelatine restored the diurnal rhythm of motor activity, disturbed sleep/wake cycle, and sleep architecture, which effect was accompanied by an increase in MT1 receptor and BDNF expression in the hippocampus at 10:00 in CCL rats., Conclusions: These findings support the value of agomelatine as an antidepressant that can adjust circadian homeostasis of motor activity and sleep/wake cycle in a CCL model.- Published
- 2020
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23. Agomelatine alleviates neuronal loss through BDNF signaling in the post-status epilepticus model induced by kainic acid in rat.
- Author
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Tchekalarova J, Atanasova D, Kortenska L, Lazarov N, Shishmanova-Doseva M, Galchev T, and Marinov P
- Subjects
- Acetamides metabolism, Animals, Brain-Derived Neurotrophic Factor metabolism, Disease Models, Animal, Electroencephalography, Epilepsy, Temporal Lobe chemically induced, Hippocampus drug effects, Kainic Acid pharmacology, Lacosamide pharmacology, Male, Neuroprotective Agents pharmacology, Rats, Rats, Wistar, Seizures chemically induced, Seizures physiopathology, Signal Transduction, Status Epilepticus chemically induced, Acetamides pharmacology, Neurons drug effects, Status Epilepticus physiopathology
- Abstract
Recently, we have reported that while agomelatine (Ago) is unable to prevent development of epilepsy it exerts a strong neuroprotective and anti-inflammatory response in the KA post-status epilepticus (SE) rat model. In the present study, we aimed to explore whether the brain-derived neurotrophic factor (BDNF) in the hippocampus is involved in the neuroprotective effect of Ago against the KA-induced SE and epileptiform activity four months later in rats. Lacosamide (LCM) was used as a positive control. The EEG-recorded seizure activity was also evaluated in two treatment protocols. In Experiment#1, Ago given repeatedly at a dose of 40 mg/kg during the course of SE was unable neither to modify EEG-recorded epileptiform activity nor the video- and EEG-recorded spontaneous seizures four months later compared to LCM (50 mg/kg). However, both Ago and LCM inhibited the expression of BDNF in the mossy fibers and also prevented neuronal loss in the dorsal hippocampal and the piriform cortex after SE. In Experiment#2, acute injection of Ago and LCM on epileptic rats, characterized by high seizure rates, did not prevent EEG-recorded paroxysmal events while only LCM decreased either absolute or relative powers of gamma (28-60 Hz) and high (HI) (60-120 Hz) frequency bands to baseline in the frontal and parietal cortex, respectively. Our results suggest that the protection against neuronal loss in specific limbic regions and overexpressed BDNF in the mossy fibers resulting from the repeated treatment with Ago and LCM, respectively, during SE is not a prerequisite for alleviation of epileptogenesis and development of epilepsy. In addition, a reduction of gamma and HI bands in the frontal and parietal cortex is not associated with EEG-recorded paroxysmal events after acute injection of LCM., (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Published
- 2019
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24. Antidepressant agomelatine attenuates behavioral deficits and concomitant pathology observed in streptozotocin-induced model of Alzheimer's disease in male rats.
- Author
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Ilieva K, Tchekalarova J, Atanasova D, Kortenska L, and Atanasova M
- Subjects
- Alzheimer Disease pathology, Alzheimer Disease physiopathology, Animals, Anxiety metabolism, Anxiety pathology, Anxiety physiopathology, Disease Models, Animal, Exploratory Behavior drug effects, Hippocampus drug effects, Male, Maze Learning drug effects, Melatonin metabolism, Memory Disorders chemically induced, Memory Disorders metabolism, Memory Disorders pathology, Rats, Rats, Sprague-Dawley, Acetamides pharmacology, Alzheimer Disease chemically induced, Antidepressive Agents pharmacology, Behavior, Animal drug effects, Streptozocin
- Abstract
Experimental findings suggest that the melatonin system has a beneficial role in models of Alzheimer's disease (ADs). The aim of the present study was to explore whether the atypical antidepressant agomelatine (Ago), which is a melatonin MT
1 and MT2 agonist and 5-HT2C antagonist, is effective against behavioral, biochemical and histological impairments in streptozotocin (STZ)-induced model of ADs in male rats. Male Sprague Dawley rats were treated intraperitoneally (i.p.) with Ago (40 mg/kg) for 30 days starting three months following the intracerebroventricular (icv) injection of STZ. Chronic Ago treatment reduced anxiety-like behavior of STZ-treated rats in the elevated plus maze, increased the preference to saccharine and corrected the spatial memory impairment in the eight-arm radial arm maze test. This melatonin analogue restored STZ-induced biochemical changes, including an increase of beta amyloid (Aβ) protein, and signal markers of inflammation (TNF-alpha and IL-1 beta). Ago exerted partial neuroprotection, specifically in the temporal CA3b subfield of the dorsal hippocampus and temporal piriform cortex. The ability of Ago to alleviate behavioral symptoms and concomitant neuropathological events observed in a model of sporadic ADs suggests that this melatonin alternative can be considered a promising adjuvant in this disease., (Copyright © 2018 Elsevier Inc. All rights reserved.)- Published
- 2019
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25. Chronic agomelatine treatment prevents comorbid depression in the post-status epilepticus model of acquired epilepsy through suppression of inflammatory signaling.
- Author
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Tchekalarova J, Atanasova D, Kortenska L, Atanasova M, and Lazarov N
- Subjects
- Animals, Comorbidity, Depression metabolism, Depression physiopathology, Hypnotics and Sedatives administration & dosage, Inflammation Mediators metabolism, Male, Rats, Rats, Wistar, Signal Transduction drug effects, Signal Transduction physiology, Status Epilepticus metabolism, Status Epilepticus physiopathology, Treatment Outcome, Acetamides administration & dosage, Antidepressive Agents administration & dosage, Depression prevention & control, Disease Models, Animal, Inflammation Mediators antagonists & inhibitors, Status Epilepticus drug therapy
- Abstract
Inflammatory signal molecules are suggested to be involved in the mechanism underlying comorbid depression in epilepsy. In the present study, we tested the hypothesis that the novel antidepressant agomelatine, a potent melatonin MT
1 and MT2 receptor agonist and serotonin 5HT2C receptor antagonist, can prevent depressive symptoms developed during the chronic epileptic phase by suppressing an inflammatory response. Chronic treatment with agomelatine (40 mg/kg, i.p.) was initiated an hour after the kainate acid (KA)-induced status epilepticus (SE) and maintained for a period of 10 weeks in Wistar rats. Registration of spontaneous motor seizures was performed through a video (24 h/day) and EEG monitoring. Antidepressant activity of agomelatine was explored in the splash test, sucrose preference test (SPT) and forced swimming test (FST) while anxiolytic effect was observed through the novelty suppression-feeding test (NSFT) during chronic phase in epileptic rats. The frequency of motor seizures detected by video and EEG recording did not differ between vehicle and Ago group. Rats with registered spontaneous motor seizures showed symptoms typical for depressive behavior that included decreased grooming, anhedonia during the dark period and hopeless-like behavior. Epileptic rats exhibited also anxiety with novelty-induced hypophagia. This behavioral deficit correlated with increased signal markers of inflammation (plasma levels of interleukin (IL)-1β and activated glia in brain), while plasma corticosterone levels were not changed. Agomelatine treatment during epileptogenesis exerted a clear antidepressant effect by suppressing all behavioral hallmarks, reducing plasma IL-1β levels and preventing microgliosis and astrogliosis in specific limbic regions. The present results suggest that agomelatine treatment starting after SE can provide an effective therapy of comorbid depression in chronic epileptic condition through suppression of inflammatory signaling., (Copyright © 2018 Elsevier Inc. All rights reserved.)- Published
- 2018
- Full Text
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26. Agomelatine protects against neuronal damage without preventing epileptogenesis in the kainate model of temporal lobe epilepsy.
- Author
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Tchekalarova J, Atanasova D, Nenchovska Z, Atanasova M, Kortenska L, Gesheva R, and Lazarov N
- Subjects
- Adaptation, Ocular drug effects, Analysis of Variance, Animals, Anxiety drug therapy, Anxiety etiology, Body Weight drug effects, Disease Models, Animal, Epilepsy, Temporal Lobe chemically induced, Epilepsy, Temporal Lobe drug therapy, Excitatory Amino Acid Agonists toxicity, Exploratory Behavior drug effects, Hypnotics and Sedatives therapeutic use, Kainic Acid toxicity, Male, Maze Learning drug effects, Motor Activity drug effects, Rats, Rats, Wistar, Time Factors, Acetamides therapeutic use, Epilepsy, Temporal Lobe pathology, Epilepsy, Temporal Lobe prevention & control, Hippocampus pathology, Neurons drug effects
- Abstract
Recent studies about the novel antidepressant agomelatine, which is a mixed MT
1 and MT2 melatonin receptor agonist and 5HT2C serotonin receptor antagonist possessing an anticonvulsant and neuroprotective action, suggest that it may have potential to contribute against epileptogenesis and epilepsy-induced memory impairment. In order to ascertain whether protection of some brain structures could suppress epileptogenesis, in the present study, we evaluated the effect of chronic post-status treatment with agomelatine on epileptogenesis, behavioral and neuronal damage induced by kainate acid (KA) status epilepticus (SE). Agomelatine/vehicle treatment (40mg/kg, i.p.) started one hour after SE and continued up to 10weeks in Wistar rats. Latency for onset of spontaneous motor seizures (SMS) and their frequency was detected by a 24-h video-recording. Locomotor activity, anxiety and hippocampus-dependent spatial memory in open field (OF), elevated plus maze (EPM), light-dark test (LDT) and radial arm maze (RAM) test, respectively, were evaluated during the last two weeks after SE. Agomelatine significantly decreased the latency for onset of SMS and increased the seizure frequency during the 2nd and the 3rd week of treatment. The MT1 and MT2 receptor agonist and serotonin 5HT2C receptor antagonist exacerbated the KA-induced hyperlocomotion and impulsive behavior and it was unable to prevent spatial memory impairment of epileptic rats. However, agomelatine induced a neuroprotection in the dorsal hippocampus, specifically in the CA1, septal CA2 and partially in the CA3c region, the hilus of the dentate gyrus, piriform cortex and septo-temporal and temporal basolateral amygdala. Our findings suggest that the beneficial impact against SE-induced neuronal loss exerted by agomelatine is not crucial for the suppression of epileptogenesis and its deleterious consequences in KA model of temporal lobe epilepsy., (Copyright © 2017 Elsevier Inc. All rights reserved.)- Published
- 2017
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27. Long-Term Treatment with Losartan Attenuates Seizure Activity and Neuronal Damage Without Affecting Behavioral Changes in a Model of Co-morbid Hypertension and Epilepsy.
- Author
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Tchekalarova JD, Ivanova N, Atanasova D, Pechlivanova DM, Lazarov N, Kortenska L, Mitreva R, Lozanov V, and Stoynev A
- Subjects
- Animals, Disease Models, Animal, Hypertension complications, Losartan administration & dosage, Male, Rats, Rats, Inbred SHR, Seizures complications, Seizures physiopathology, Status Epilepticus chemically induced, Behavior, Animal drug effects, Hippocampus drug effects, Hypertension physiopathology, Losartan pharmacology, Neurons drug effects, Seizures drug therapy
- Abstract
Over the last 10 years, accumulated experimental and clinical evidence has supported the idea that AT1 receptor subtype is involved in epilepsy. Recently, we have shown that the selective AT1 receptor antagonist losartan attenuates epileptogenesis and exerts neuroprotection in the CA1 area of the hippocampus in epileptic Wistar rats. This study aimed to verify the efficacy of long-term treatment with losartan (10 mg/kg) after kainate-induced status epilepticus (SE) on seizure activity, behavioral and biochemical changes, and neuronal damage in a model of co-morbid hypertension and epilepsy. Spontaneous seizures were video- and EEG-monitored in spontaneously hypertensive rats (SHRs) for a 16-week period after SE. The behavior was analyzed by open field, elevated plus maze, sugar preference test, and forced swim test. The levels of serotonin in the hippocampus and neuronal loss were estimated by HPLC and hematoxylin and eosin staining, respectively. The AT1 receptor antagonism delayed the onset of seizures and alleviated their frequency and duration during and after discontinuation of treatment. Losartan showed neuroprotection mostly in the CA3 area of the hippocampus and the septo-temporal hilus of the dentate gyrus in SHRs. However, the AT1 receptor antagonist did not exert a substantial influence on concomitant with epilepsy behavioral changes and decreased 5-HT levels in the hippocampus. Our results suggest that the antihypertensive therapy with an AT1 receptor blocker might be effective against seizure activity and neuronal damage in a co-morbid hypertension and epilepsy.
- Published
- 2016
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28. Comparative power spectrum analysis of EEG activity in spontaneously hypertensive and Wistar rats in kainate model of temporal model of epilepsy.
- Author
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Tchekalarova J, Kortenska L, Marinov P, and Boyanov K
- Subjects
- Animals, Blood Pressure, Brain Mapping, Brain Waves drug effects, Brain Waves genetics, Disease Models, Animal, Electroencephalography, Male, Rats, Rats, Inbred SHR, Rats, Wistar, Brain Waves physiology, Epilepsy chemically induced, Epilepsy physiopathology, Excitatory Amino Acid Agonists toxicity, Kainic Acid toxicity, Spectrum Analysis
- Abstract
Recently, we have reported that spontaneously hypertensive rats (SHRs) exhibit higher susceptibility than Wistar rats in kainate (KA) model of epilepsy. The aim of the present study is to compare the baseline of EEG signals in SHRs and Wistar rats using Discrete Fourier transform (DFT) during the three phases of KA model (acute, latent and chronic). The SHRs showed higher baseline relative power of delta waves in the left frontal cortex and lower gamma-HF waves in the left frontal and left/right parietal cortex, respectively, compared to Wistar rats. During the acute phase, both absolute and relative power of fast EEG bands (gamma-HF) was lower in the left/right frontal and the left/right parietal cortex in SHRs compared to Wistar rats. During the latent phase, no difference in the power of the investigated bands was detected between the two strains. During the chronic epileptic phase, the SHRs were characterized with higher power of HF oscillations than Wistar rats both in the frontal and parietal cortex without brain lateralization while theta, alpha and beta bands were with diminished power in the left parietal cortex of SHRs compared to normotensive Wistar rats. Taken together, the presented results suggest that the increased delta waves and lower gamma-HF waves in the frontal/parietal cortex are associated with a higher seizure susceptibility of SHRs compared to Wistar rats while fastest oscillations has a critical role in seizure generation and propagation of hypertensive rats., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2016
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29. Consequences of long-term treatment with agomelatine on depressive-like behavior and neurobiological abnormalities in pinealectomized rats.
- Author
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Tchekalarova J, Nenchovska Z, Atanasova D, Atanasova M, Kortenska L, Stefanova M, Alova L, and Lazarov N
- Subjects
- Adaptation, Ocular drug effects, Analysis of Variance, Animals, Body Weight drug effects, Depressive Disorder pathology, Drug Administration Schedule, Exploratory Behavior drug effects, Food Preferences drug effects, Hippocampus drug effects, Hippocampus metabolism, Male, Maze Learning drug effects, Rats, Rats, Wistar, Serotonin metabolism, Swimming psychology, Time Factors, Tritium metabolism, Acetamides therapeutic use, Depressive Disorder etiology, Depressive Disorder prevention & control, Hypnotics and Sedatives therapeutic use, Pineal Gland injuries, Pineal Gland physiology
- Abstract
Previous data have shown that the rat model of melatonin deficit can cause a number of neurobiological aberrations. The aim of the present study was to determine whether the antidepressant drug agomelatine, a MT1/MT2 melatoninergic receptor agonist/5-HT2C receptor antagonist is able to prevent some of the behavioral, biochemical and cellular abnormalities induced by pinealectomy. The injection of agomelatine (40 mg/kg, i.p. for 5 weeks)/vehicle started after pinealectomy/sham procedure in Wistar rats. Animals were tested in different behavioral tests for anxiety and depression during the period of agomelatine treatment (chronic effect) and two months later (plastic effect). The effect of agomelatine on KCl-evoked serotonin (5-HT) release from the hippocampus, the activity of the hypothalamic-pituitary-adrenal (HPA) axis and neuronal loss in pinealectomized rats were assessed. Our results showed that agomelatine not only did not prevent the disturbed emotional arousal/anxiety behavior in pinealectomized rats during the treatment but the enhanced motor activity and decreased anxiety state was still observed two months after the discontinuation of treatment. However, the drug corrected a depressive-like behavior (chronic and plastic effect), alleviated the enhanced KCl-evoked 5-HT release in the hippocampus, recovered the suppressed negative feedback inhibition of HPA axis and exerted a neuroprotection in pinealectomized rats. Our findings suggest that pinealectomy can model melancholic depression disorder while the antidepressant action of agomelatine is associated with a correction of 5-HT release in the hippocampus, dysregulated HPA system and neuroprotection in limbic structures., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2016
- Full Text
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30. Antiepileptogenic and neuroprotective effects of losartan in kainate model of temporal lobe epilepsy.
- Author
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Tchekalarova JD, Ivanova NM, Pechlivanova DM, Atanasova D, Lazarov N, Kortenska L, Mitreva R, Lozanov V, and Stoynev A
- Subjects
- Angiotensin II Type 1 Receptor Blockers therapeutic use, Animals, Male, Random Allocation, Rats, Rats, Wistar, Treatment Outcome, Anticonvulsants therapeutic use, Epilepsy, Temporal Lobe chemically induced, Epilepsy, Temporal Lobe drug therapy, Kainic Acid toxicity, Losartan therapeutic use, Neuroprotective Agents therapeutic use
- Abstract
Recently, we have shown that the blockade of AT1 receptor might be useful as an adjuvant treatment strategy for the prevention of oxidative stress and neurotoxicity caused by status epilepticus (SE) in rats. The purpose of the present study was to further assess the efficacy of long-term treatment with losartan (10mg/kg), the selective AT1 receptor antagonist, during kainate (KA)-induced epileptogenesis in Wistar rats. Losartan treatment started after onset of SE and continued for 4weeks. The rats were video- and EEG-recorded for 3months. Locomotor activity, anxiety and depressive-like behavior were evaluated 9weeks after SE, when all rats had developed chronic epileptic state. Neuronal damage in hippocampus was analyzed by hematoxylin while serotonin (5-HT) levels in hippocampus by HPLC. AT1 receptor antagonism increased the latent seizure-free period and decreased the frequency of spontaneous motor seizures. Losartan positively affected epilepsy-provoked behavioral changes, including impulsivity, low anxiety level and depression in a phase-dependent manner and restored the changes in diurnal fluctuation of motor activity. Losartan exerted neuroprotection selectively in the CA1 area of the hippocampus in the KA-treated rats and lowered the 5-HT levels both in normal and abnormal conditions. Our findings suggest that the AT1 receptor antagonist exerts disease-modifying effects during KA-induced epileptogenesis and neuronal damage in CA1 hippocampal area, attenuated some of the behavioral changes and restored diurnal variability in locomotor activity., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
- Full Text
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31. Treatment with melatonin after status epilepticus attenuates seizure activity and neuronal damage but does not prevent the disturbance in diurnal rhythms and behavioral alterations in spontaneously hypertensive rats in kainate model of temporal lobe epilepsy.
- Author
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Petkova Z, Tchekalarova J, Pechlivanova D, Moyanova S, Kortenska L, Mitreva R, Popov D, Markova P, Lozanov V, Atanasova D, Lazarov N, and Stoynev A
- Subjects
- Animals, Antioxidants pharmacology, Blood Pressure drug effects, Body Weight drug effects, Brain drug effects, Circadian Rhythm drug effects, Disease Models, Animal, Epilepsy, Temporal Lobe chemically induced, Exploratory Behavior drug effects, Food Preferences drug effects, Kainic Acid toxicity, Male, Maze Learning drug effects, Melatonin pharmacology, Rats, Rats, Inbred SHR, Serotonin metabolism, Swimming psychology, Time Factors, Antioxidants therapeutic use, Behavior, Animal drug effects, Brain pathology, Epilepsy, Temporal Lobe drug therapy, Epilepsy, Temporal Lobe physiopathology, Melatonin therapeutic use
- Abstract
Melatonin is involved in the control of circadian and seasonal rhythmicity, possesses potent antioxidant activity, and exerts a neuroprotective and anticonvulsant effect. Spontaneously hypertensive rats (SHRs) are widely accepted as an experimental model of essential hypertension with hyperactivity, deficient sustained attention, and alterations in circadian autonomic profiles. The purpose of the present study was to determine whether melatonin treatment during epileptogenesis can prevent the deleterious consequences of status epilepticus (SE) in SHRs in the kainate (KA) model of temporal lobe of epilepsy (TLE). Spontaneous recurrent seizures (SRSs) were EEG- and video-recorded during and after the treatment protocol. Melatonin (10mg/kg diluted in drinking water, 8weeks) increased the seizure-latent period, decreased the frequency of SRSs, and attenuated the circadian rhythm of seizure activity in SHRs. However, melatonin was unable to affect the disturbed diurnal rhythms and behavioral changes associated with epilepsy, including the decreased anxiety level, depression, and impaired spatial memory. Melatonin reduced neuronal damage specifically in the CA1 area of the hippocampus and piriform cortex and decreased hippocampal serotonin (5-HT) levels both in control and epileptic SHRs. Although long-term melatonin treatment after SE shows a potential to attenuate seizure activity and neuronal loss, it is unable to restore epilepsy-associated behavioral abnormalities in SHRs., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
32. Prophylactic treatment with melatonin after status epilepticus: effects on epileptogenesis, neuronal damage, and behavioral changes in a kainate model of temporal lobe epilepsy.
- Author
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Tchekalarova J, Petkova Z, Pechlivanova D, Moyanova S, Kortenska L, Mitreva R, Lozanov V, Atanasova D, Lazarov N, and Stoynev A
- Subjects
- Analysis of Variance, Animals, Chromatography, High Pressure Liquid, Depression etiology, Electroencephalography, Excitatory Amino Acid Agonists toxicity, Exploratory Behavior drug effects, Hippocampus drug effects, Hippocampus metabolism, Hippocampus pathology, Hyperkinesis etiology, Kainic Acid toxicity, Kaplan-Meier Estimate, Male, Maze Learning drug effects, Neurons pathology, Rats, Rats, Wistar, Serotonin metabolism, Status Epilepticus chemically induced, Status Epilepticus drug therapy, Sucrose administration & dosage, Swimming, Time Factors, Central Nervous System Depressants therapeutic use, Depression prevention & control, Hyperkinesis prevention & control, Melatonin therapeutic use, Status Epilepticus complications
- Abstract
Melatonin is a potent antioxidant which showed anticonvulsant activities both in experimental and clinical studies. In the present study, we examined the effect of melatonin treatment (10mg/kg/day, diluted in drinking water, 8 weeks) during epileptogenesis on the consequences of a kainate (KA)-induced status epilepticus (SE) in rats. Melatonin increased the latency in the appearance of spontaneous recurrent seizures (SRSs) and decreased their frequency only during the treatment period. The behavioral alterations associated with hyperactivity, depression-like behavior during the light phase, and deficits in hippocampus-dependent working memory were positively affected by melatonin treatment in rats with epilepsy. Melatonin reduced the neuronal damage in the CA1 area of the hippocampus and piriform cortex and recovered the decrease of hippocampal serotonin (5-HT) level in rats with epilepsy. Taken together, long-term melatonin treatment after SE was unable to suppress the development of epileptogenesis. However, it showed a potential in reducing some of the deleterious alterations that develop during the chronic epileptic state in a diurnal phase-dependent mode., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
- Full Text
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33. Multi-unit activity suppression and sensorimotor deficits after endothelin-1-induced middle cerebral artery occlusion in conscious rats.
- Author
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Moyanova S, Kirov R, and Kortenska L
- Subjects
- Action Potentials drug effects, Action Potentials physiology, Analysis of Variance, Animals, Behavior, Animal drug effects, Cerebral Cortex physiopathology, Consciousness, Disease Models, Animal, Dominance, Cerebral, Endothelin-1, Infarction, Middle Cerebral Artery chemically induced, Male, Microinjections, Posture, Rats, Infarction, Middle Cerebral Artery physiopathology, Psychomotor Performance physiology
- Abstract
Conscious Wistar rats with stereotaxically and unilaterally implanted cannula just above the middle cerebral artery (MCA) were injected with the powerful vasoconstrictor peptide endothelin-1 (ET1, 60 pmol in 3 microl). The purpose was to examine the long-term (from the 1st to the 14th day) changes in neuronal bioelectrical activity together with sensorimotor deficits after ET1-induced MCA occlusion (MCAO). Extracellular multi-unit activity (MUA) recorded from the ipsilateral fronto-parietal cortical area (supplied by MCA) and sensorimotor behavior (one postural reflex test and six limb placing tests) were examined. A significant suppression of the multi-unit activity was observed until the 14th day post-ET1. The rats exhibited significant unilateral sensorimotor deficits with a maximum at the 3-7 days after ET1 and a spontaneous partial recovery by days 11-14. A significant correlation was found between the suppression of the multi-unit activity and the sensorimotor deficits between the 3rd and the 10th day post-ET1. The results suggest that studying the bioelectrical activity in combination with the behavioral sensorimotor functions may be of use to assess the functional disturbances associated with focal cerebral ischemia and would help to examine the therapeutic benefits of various cerebroprotective treatments before initiating human clinical trials.
- Published
- 2003
- Full Text
- View/download PDF
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