V. Bubenikova-Valesova’s research while affiliated with National Institute of Mental Health and other places

Chronic methamphetamine (meth) abuse often turns into a compulsive drug-taking disorder accompanied by persistent cognitive deficits and re-occurring psychosis. Possible common neurobiological substrates underlying meth-induced deficits and schizophrenia remain poorly understood. Serotonin 2A (5-HT2A) and metabotropic glutamate 2 (mGlu2) receptors co-regulate psychosis-like behaviors and cognitive function in animals. Therefore, in the present study we examined the effects of chronic exposure to three different drugs known to produce persistent deficits in sensorimotor gating and cognition [meth, phencyclidine (PCP) and MK-801] on the expression of 5-HT2A and mGlu2 within the rat medial prefrontal cortex (PFC), dorsal hippocampus (dHPC) and perirhinal cortex (PRh). Adult male rats underwent 14 days of: (a) meth self-administration (6 h/day), (b) phencyclidine (PCP; 5 mg/kg, twice/day) administration, or (c) MK-801 (0.3 mg/kg, twice/day) administration. Seven days after the discontinuation of drug administration, tissues of interest were collected for protein expression analysis. We found that despite different pharmacological mechanism of action, chronic meth, PCP, and MK-801 similarly dysregulated 5-HT2A and mGlu2, as indicated by an increase in the 5-HT2A/mGlu2 expression ratio in the mPFC (all three tested drugs), PRh (meth and PCP), and dHPC (MK-801 only). Complementary changes in G-protein expression (increase in Gαq and decrease in Gαi) were also observed in the mPFC of meth animals. Finally, we found that 5-HT2A/mGlu2 cooperation can be mediated in part by the formation of the receptor heteromer in some, but not all cortical regions. In summary, these data suggest that a shift towards increased availability (and G-protein coupling) of cortical 5-HT2A vs. mGlu2 receptors may represent a common neurobiological mechanism underlying the emergence of psychosis and cognitive deficits observed in subjects with meth use disorder and schizophrenia.

Chronic methamphetamine (METH) abuse has been shown to elicit strong neurotoxic effects. Yet, with an increasing number of children born to METH abusing mothers maturing into adulthood, one important question is how far do the neurotoxic effects of METH alter various neurotransmitter systems in the adult METH-exposed offspring. The purpose of this study was to investigate long-term trans-generational neurochemical changes, following prenatal methamphetamine exposure, in the adult Wistar rat brain. METH or saline (SAL – control animals) was administered to pregnant dams throughout the entire gestation period (G0-G22). At postnatal day 90, dopamine, serotonin, glutamate and GABA were measured in the adult brain before (baseline) and after a METH re-administration using in-vivo microdialysis and liquid chromatography/mass spectrometry. The results show that METH-exposure increased basal levels of monoamines and glutamate, but decreased GABA levels in all measured brain regions. Acute challenge with METH injection in the METH-exposed group induced a lower increase in monoamine system relative to the increase in the GABAergic and glutamatergic system. The data shows that prenatal METH exposure has strong effects on the monoaminergic, GABAergic and glutamatergic system even when exposure to METH was limited to the prenatal phase. Toxicological effects of METH have therefore longer lasting effects as currently considered and seem to affect the excitatory-inhibitory balance in the brain having strong implications for cognitive and behavioral functioning.

The use of methamphetamine (MA) among pregnant women is an increasing world-wide health problem. Prenatal MA exposure may cause changes in foetus but the exact effects have remained unclear. The aim of this study is to present the effect of prenatal MA exposure on recognition memory in adult rats. Adult female Wistar rats were injected daily with D-methamphetamine HCl (MA; 5 mg/kg, s.c.) during the entire gestation period. Control females were treated with saline in the same regime. Adult male offspring was administrated acutely by MA (1 mg/kg i.p.) or saline 30 minutes before beginning of an experiment. For testing recognition memory two tasks were chosen: Novel Object Recognition Test (NORT) and Object Location Test (OLT). Our results demonstrate that prenatally MA-exposed animals were worse in NORT independently on an acute administration of MA in adulthood. Prenatally MA-exposed rats did not deteriorate in OLT, but after acute administration of MA in adulthood, there was significant worsening compared to appropriate control. Prenatally saline-exposed offspring did not deteriorate in any test even after acute administration of MA. Our data suggest that prenatal MA exposure in rats cause impairment in recognition memory in adult offspring, but not in spatial memory. In addition, acute administration of MA to controls did not deteriorate either recognition or spatial memory.

Since close relationship was shown between drug addiction and memory formation, the aim of the present study was to investigate the effects of interaction between prenatal methamphetamine (MA) exposure and MA treatment in adulthood on spatial and non-spatial memory and on the structure of the N-methyl-D-aspartate (NMDA) receptors in the hippocampus. Adult male rats prenatally exposed to MA (5 mg/kg) or saline were tested in adulthood. Non-spatial memory was examined in the Object Recognition Test (ORT) and spatial memory in the Object Location Test (OLT) and in the Memory Retention Test (MRT) conducted in the Morris Water Maze (MWM), respectively. Based on the type of the memory test animals were injected either acutely (ORT, OLT) or long-term (MWM) with MA (1 mg/kg). After each testing, animals were sacrificed and brains were removed. The hippocampus was then examined in Western Blot analysis for occurrence of different NMDA receptors' subtypes. Our results demonstrated that prenatal MA exposure affects the development of the NMDA receptors in the hippocampus that might correspond with improvement of spatial memory tested in adulthood in the MWM. On the other hand, the effect of prenatal MA exposure on non-spatial memory examined in the ORT was the opposite. In addition, we showed that the effect of MA administration in adulthood on NMDA receptors is influenced by prenatal MA exposure, which seems to correlate with the spatial memory examined in the OLT.

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. Results: 2C-B had a biphasic effect on locomotion with initial inhibitory followed by excitatory effect; amphetamine induced only hyperlocomotion. Both drugs induced deficits in the PPI; however they had opposite effects on ASR. 2C-B increased dopamine but decreased 3,4-dihydroxyphenylacetic acid (DOPAC) in the NAc. Low doses of 2C-B induced a decrease in EEG power spectra and coherence. On the contrary, high dose of 2C-B 50 mg/kg had a temporally biphasic effect with an initial decrease followed by an increase in EEG power; decrease as well as increase in EEG coherence was observed. Amphetamine mainly induced an increase in EEG power and coherence in theta and alpha bands. Increases in the theta and alpha power and coherence in 2C-B and amphetamine were temporally linked to an increase in locomotor activity and DA levels in NAc. Conclusions: 2C-B is a centrally active compound similar to other hallucinogens, entactogens and stimulants. Increased dopamine and decreased DOPAC in the NAc may reflect its psychotomimetic and addictive potential and monoaminoxidase inhibition. Alterations in brain functional connectivity reflected the behavioral and neurochemical changes produced by the drug; a correlation between EEG changes and locomotor behavior was observed.

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. The procognitive properties were evaluated using active place avoidance on a rotating arena (Carousel maze). We evaluated effects of 3α5β-P-Glu on the avoidance, on locomotor activity, and anxiety. 3α5β-P-Glu alone altered neither spatial learning nor locomotor activity in control animals. In the model animals, 3α5β-P-Glu reversed the MK-801-induced cognitive deficit without reducing hyperlocomotion. The highest dose of 3α5β-P-Glu also showed anxiolytic properties. Taken together, 3α5β-P-Glu may participate in the restoration of normal brain functioning and these results may facilitate the development of new promising drugs improving cognitive functioning in schizophrenia.

This review focuses on the relationship between psychotropic drugs and adult hippocampal neurogenesis. Adult neurogenesis is important for learning and memory, as well as for depression and anxiety. There is some evidence that chronic treatment with opiates, stimulants and entactogens decreases neurogenesis and consequently impairs cognitive function, as well as inducing depressive-like behaviour in animals during drug withdrawal. On the other hand, NMDA receptor antagonists increase neurogenesis, but negatively affect cognitive function and have an antidepressant-like profile. We suggest that drug-induced changes in neurogenesis have a greater and more concise effect on emotive state reflecting the direction of influencing new cells proliferation than the performance of cognitive tasks. In this review we provide some evidence for this assumption.

During the last decades it became apparent from experimental studies that catecholamine neurotransmission is one of focal point of neuroscience research. Dopamine metabolism plays a key role in many neuropsychiatric diseases. The proposed work will be oriented into the emerging field of neurochemistry and will provide an overview of recent techniques used for the analysis of dopamine and its precursors (= biosynthesis) - tyrosine, L-DOPA and its metabolites (= biodegradation) - homovanillic acid (HVA), 3,4-dihydroxyphenylacetic acid (DOPAC), and 3-methoxytyramine (3-MT) from biological samples such as cerebrospinal fluid (CSF), plasma, brain tissue, etc. The analytical determination consists in sample preparation and detection techniques. Various sampling methods (microdialysis, biopsy, etc.) will be discussed as well as broad range of pre-treatment methods used for preparation of suitable sample for analytical determination (quantitative or/and qualitative). The main attention will be paid to the spectrum of detection methods used for determination of dopamine and its precursors/metabolites in neurosciences. The use of biochemical methods as RIA (Radioimmunoassay), EIA (Enzyme Immunoassay), ELISA (Enzyme Linked Immunosorbent Assay) etc. and their comparison to detection methods including fluorescence (FL), chemiluminescence (CL), ultraviolet (UV), electrochemical (EC), mass spectrometry (MS) methods coupled with separation techniques (chromatographic: gas-liquid chromatography (GC), high-performance liquid chromatography (HPLC), etc.) will be described in details. In general, biochemical methods have demonstrated a lower-order detection limit than those commonly achieved by above mentioned detection techniques however, the LOD of the latter instrumental methods have dropped to pico-, femto- or even attomolar levels during the last decade, sufficient for the detection of most biologically active substances in humans. In comparison with biochemical methods, connecting liquid or gas chromatography to mass spectrometry not only offers precise quantitative data but also valuable structural information (qualitative information). Employing the MSn techniques offers the development of highly specific methods, inherently eliminating false positive/negative results. This is in contrast to immunochemical or enzymatic biochemical methods, whose design in principle allows "cross-linked reactions" leading to an occurrence of these errors. The work will descriebe all the methods used in determination of concentration levels of dopamine and its precursors, metabolitates as well as their glory and pitfalls in neuroscience practice. It will be also demonstrated that precise quantification of dopamine and its metabolites concentration levels in particular body liquids or brain area may contribute to a better understanding of the pathophysiology and pathogenesis of many neuropsychiatric disorders (e.g. drug addiction, schizophrenia, Parkinson's and Alzheimer's disease) and to pharmaceutical research of new drugs.