Publications by authors named "Lukas Rambousek"

Epilepsy is a disabling, chronic brain disease,affecting ~1% of the World's population, characterized by recurrent seizures (sudden, uncontrolled brain activity), which may manifest with motor symptoms (e.g., convulsions) or non-motor symptoms.

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Neuroactive steroid 20-oxo-5β-pregnan-3α-yl L-glutamyl 1-ester (PA-Glu), a synthetic analogue of naturally occurring 20-oxo-5β-pregnan-3α-yl sulfate (pregnanolone sulfate, PA-S), inhibits N-methyl-D-aspartate (NMDA) receptors and possesses neuroprotective properties and minimal adverse effects. Herein, we report in vivo effects of new structural modifications of the PA-S molecule: a nonpolar modification of the steroid D-ring (5β-androstan-3α-yl L-glutamyl 1-ester, AND-Glu), attachment of a positively charged group to C3 (20-oxo-5β-pregnan-3α-yl L-argininate dihydrochloride salt, PA-Arg) and their combination (5β-androstan-3α-yl L-argininate dihydrochloride salt, AND-Arg). The first aim of this study was to determine the structure-activity relationship for neuroprotective effects in a model of excitotoxic hippocampal damage in rats, based on its behavioral correlate in Carousel maze.

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Epilepsy is a widespread neurological disease characterized by abnormal neuronal activity resulting in recurrent seizures. There is mounting evidence that a circadian system disruption, involving clock genes and their downstream transcriptional regulators, is associated with epilepsy. In this study, we characterized the hippocampal expression of clock genes and PAR bZIP transcription factors (TFs) in a mouse model of temporal lobe epilepsy induced by intrahippocampal injection of kainic acid (KA).

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Aberrant epileptic activity is detectable at early disease stages in Alzheimer's disease (AD) patients and in AD mouse models. Here, we investigated in young ArcticAβ mice whether AD-like pathology renders neuronal networks more susceptible to the development of acquired epilepsy induced by unilateral intrahippocampal injection of kainic acid (IHK). In this temporal lobe epilepsy model, IHK induces a status epilepticus followed after two weeks by spontaneous recurrent seizures (SRS).

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Excessive stimulation of NMDA receptors with glutamate or other potent agonists such as NMDA leads to excitotoxicity and neural injury. In this study, we aimed to provide insight into an animal model of brain excitotoxic damage; single unilateral infusion of NMDA at mild dose into the hippocampal formation. NMDA infusion induced chronic, focal neurodegeneration in the proximity of the injection site.

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The involvement of the serotonin system in the pathophysiology of schizophrenia has been elucidated by experiments with hallucinogens. Application of a hallucinogen to humans leads to changes in perception, cognition, emotions, and induction of psychotic-like symptoms that resemble symptoms of schizophrenia. In rodent studies, their acute administration affects sensorimotor gating, locomotor activity, social behavior, and cognition including working memory, the phenotypes are considered as an animal model of schizophrenia.

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Background: Methamphetamine (METH) abuse is a growing health problem worldwide, and METH use during pregnancy not only endangers the mother's health but also the developing fetus. To provide better insight into these risks, we performed the following experiments.

Method: First, we investigated how sex influences the pharmacokinetics of METH and amphetamine (AMP) in male and female rats.

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Rationale And Objectives: Behavioral, neurochemical and pharmaco-EEG profiles of a new synthetic drug 4-bromo-2,5-dimethoxyphenethylamine (2C-B) in rats were examined.

Materials And Methods: Locomotor effects, prepulse inhibition (PPI) of acoustic startle reaction (ASR), dopamine and its metabolite levels in nucleus accumbens (NAc), EEG power spectra and coherence in freely moving rats were analysed. Amphetamine was used as a reference compound.

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Neuroactive steroids modulate receptors for neurotransmitters in the brain and thus might be efficacious in the treatment of various diseases of the central nervous system such as schizophrenia. We have designed and synthetized a novel use-dependent NMDA receptor antagonist 3α5β-pregnanolone glutamate (3α5β-P-Glu). In this study, we evaluate procognitive properties of 3α5β-P-Glu in an animal model of schizophrenia induced by systemic application of MK-801.

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A sensitive assay method was developed for a parallel, rapid and precise determination of dopamine and its metabolites, homovanillic acid, 3-methoxytyramine and 3,4-dihydroxyphenylacetic acid, from brain microdialysates. The method consisted of a pre-treatment step, freeze-drying (lyophilization), to concentrate dopamine and its metabolites from the microdialysates, and a detection step using liquid chromatography combined with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). In particular, the reaction monitoring mode was selected for its extremely high degree of selectivity and the stable-isotope-dilution assay for its high precision of quantification.

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Preclinical studies have demonstrated a considerable role for N-methyl-d-aspartate (NMDA) receptors in excitotoxicity and the concurrent neuroprotective effect of NMDA receptor antagonists. Because NMDA receptors are one of the most widespread receptors in the central nervous system, application of their antagonist often leads to serious side effects ranging from motor impairment to induction of schizophrenic-like psychosis. Therefore, we have initiated development and testing of a novel synthetic NMDA receptor antagonist derived from naturally occurring neurosteroids.

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Article Synopsis
  • * Prenatal exposure to methamphetamine resulted in increased basal dopamine and its metabolites in the nucleus accumbens of adult male offspring, leading to reduced immobility.
  • * Adult rats exposed to methamphetamine before birth exhibited heightened locomotion and rearing in response to a methamphetamine challenge, indicating increased sensitivity to the drug.
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Dopamine-mediated neurotransmission is widely studied with respect to motivation, motor activity and cognitive processes. The aim of the present study was to evaluate the role of D2 receptors in the behavior of rats in the active allothetic place avoidance (AAPA) task. D2 receptor agonist quinpirole and antagonist sulpiride were administered intraperitoneally 20min prior to behavioral testing.

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