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Dive into the research topics where Karl-Artur Kovar is active.

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Featured researches published by Karl-Artur Kovar.


Psychopharmacology | 1999

Psychopathological, neuroendocrine and autonomic effects of 3,4-methylenedioxyethylamphetamine (MDE), psilocybin and d-methamphetamine in healthy volunteers. Results of an experimental double-blind placebo-controlled study.

E. Gouzoulis-Mayfrank; B. Thelen; E. Habermeyer; H. J. Kunert; Karl-Artur Kovar; H. Lindenblatt; L. Hermle; Manfred Spitzer; H. Sass

Abstract The aim of this study was to contribute to the characterization of the entactogen (ecstasy) substance group. The psychopathological, neuroendocrine and autonomic effects of common recreational doses of the entactogen 3,4-methylenedioxyethylamphetamine (MDE), the hallucinogen psilocybin, the stimulant d-methamphetamine and placebo were investigated in a double-blind study with healthy volunteers (n = 32). Psychological effects of the drugs were assessed by means of standardized rating scales, self assessment inventories and free descriptions. The most characteristic effects of MDE were pleasant emotional experiences of relaxation, peacefulness, content and closeness to others. However, significant stimulant and hallucinogen-like effects were also present, although the latter were weaker than the effects of psilocybin. MDE elicited the strongest endocrine and autonomic effects among the three drugs, including robust rises of serum cortisol and prolactin, elevations of blood pressure and heart rate, and a moderate, but significant rise of body temperature. The apparent contrast between psychological and autonomic effects (subjective relaxation versus physical activation) was a unique feature of the MDE state. Our findings are in line with both users’ reports and results from previous experimental studies, and support the view that entactogens constitute a distinct psychoactive substance class taking an intermediate position between hallucinogens and stimulants.


Neuropsychopharmacology | 1999

Neurometabolic Effects of Psilocybin, 3,4-Methylenedioxyethylamphetamine (MDE) and d-Methamphetamine in Healthy Volunteers A Double-Blind, Placebo-Controlled PET Study with [18F]FDG

Euphrosyne Gouzoulis-Mayfrank; Mathias Schreckenberger; Osama Sabri; Christoph Arning; Bernhard Thelen; Manfred Spitzer; Karl-Artur Kovar; Leopold Hermle; Udalrich Büll; Henning Sass

The neurometabolic effects of the hallucinogen psilocybin (PSI; 0.2 mg/kg), the entactogen 3,4-methylenedioxyethylamphetamine (MDE; 2 mg/kg) and the stimulant d-methamphetamine (METH; 0.2–0.4 mg/kg) and the drugs’ interactions with a prefrontal activation task were investigated in a double-blind, placebo-controlled human [F-18]fluorodeoxyglucoseFDG-positron emission tomographicPET study (each group: n = 8). Subjects underwent two scans (control: word repetition; activation: word association) within 2–4 weeks. Psilocybin increased rMRGlu in distinct right hemispheric frontotemporal cortical regions, particularly in the anterior cingulate and decreased rMRGlu in the thalamus. Both MDE and METH induced cortical hypometabolism and cerebellar hypermetabolism. In the MDE group, cortical hypometabolism was more pronounced in frontal regions, with the exception of the right anterior cingulate, which tended to be hyperactive. Cognitive activation-related increases in left frontocortical regions were attenuated under all three psychoactive substances, but less so under MDE. Taking into account performance data and subjective reports on task difficulty, these effects may result from different mechanisms across the three groups. Our PSI data are in line with studies on acute schizophrenic patients suggesting frontal overactivity at rest, but diminished capacity to activate prefrontal regions upon cognitive demand. The MDE data support the hypothesis that entactogens constitute a distinct psychoactive substance class, which takes an intermediate position between stimulants and hallucinogens.


Neuropsychopharmacology | 1993

Psychological effects of MDE in normal subjects : are entactogens a new class of psychoactive agents ?

Leo Hermle; Manfred Spitzer; Dieter Borchardt; Karl-Artur Kovar; Euphrosyne Gouzoulis

The so-called entactogens 3,4-methylenedioxymethamphetamine ([MDMA] also known as “Ecstasy,” or “Adam”) and its analog 3,4-methylenedioxyethamphetamine ([MDE] also known as “Eve”) exert similar psychotropic effects in humans. Two double-blind placebo-controlled psychometric studies with normal control subjects were conducted. Placebo or MDE (140 mg) was administered orally to eight male volunteers at 1:30 P.M. and to six subjects (3 male, 3 female) at 11 P.M. Psychologic tests and clinical ratings were performed 1 hour before the administration of the drugs, as well as 2, 5, and 24 hours after drug intake and 7 days thereafter in the first study. In the second study, measures were taken at times −1, + 8. 5, + 24 hours, and + 7 days. The majority of the psychotropic effects resembled those that have already been described in anecdotal reports. The substance produced a partially controllable state of enhanced insight, empathy, and peaceful feelings. All subjects displayed a general stimulation with increased psychomotor drive, logorrhea, and facilitation of communication. One of the fourteen volunteers developed a toxic psychosis. One volunteer displayed a dysphoric reaction, one suffered from episodes of anxiety for some days after the experiment. The findings support the hypothesis that MDMA and MDE represent a novel pharmacologic class.


Journal of Chromatography B: Biomedical Sciences and Applications | 1996

Toxicological detection of the designer drug 3,4-methylenedioxyethylamphetamine (MDE, “Eve”) and its metabolites in urine by gas chromatography — mass spectrometry and fluorescence polarization immunoassay☆

Hartmut K. Ensslin; Karl-Artur Kovar; Hans H. Maurer

Studies are presented on the toxicological detection of the designer drug methylenedioxyethylamphetamine [MDE, rac-N-ethyl-(3,4-methylenedioxyphenyl)-propane-2-amine] in urine after a single oral dose of 140 mg of MDE by GC-MS and fluorescence polarization immunoassay (FPIA). After acid hydrolysis, extraction and acetylation MDE and its metabolites could be detected by mass chromatography with the selected ions m/z 72, 86, 114, 150, 162 and 164, followed by identification of the peaks underlying full mass spectra by computer library search. The following metabolites could be detected: unchanged MDE and 3,4-dihydroxyethylamphetamine (DHE) for 33-62 h, 3,4-methylenedioxyamphetamine (MDA) for 32-36 h and 4-hydroxy-3-methoxyethylamphetamine (HME) for 7-8 days. 3,4-Dihydroxyamphetamine (DHA), 4-hydroxy-3-methoxyamphetamine (HMA), piperonyl acetone, 3,4-dihydroxyphenyl acetone and 4-hydroxy-3-methoxyphenyl acetone could only be detected in trace amounts within the first few hours. The Abbott TD x FPIA assay amphetamine/metamphetamine II gave positive results in urine for 33-62 h. Therefore, positive immunoassay results could be confirmed by the GC-MS procedure which also allowed the differentiation of MDE and its homologues 3,4-methylenedioxymethamphetamine (MDMA) and MDA as well as other amphetamine derivatives interfering with the TD x assay. Furthermore, this GC-MS procedure allowed the simultaneous detection of most of the toxicologically relevant drugs.


Neuroscience Letters | 1999

Differential effects of L-buthionine sulfoximine and ethacrynic acid on glutathione levels and mitochondrial function in PC12 cells.

Jan Seyfried; Frank Soldner; Jörg B. Schulz; Thomas Klockgether; Karl-Artur Kovar; Ullrich Wüllner

We investigated the effect of glutathione (GSH) depletion on mitochondrial function and generation of reactive oxygen intermediates (ROI) in PC12 cells in vitro. Direct depletion of cellular GSH using ethacrynic acid (EA, 500 mM) resulted in a concentration-dependent generation of ROI and cell death within 24 h. Treatment with 500 microM L-buthionine sulfoximine (BSO), which inhibits GSH synthesis, reduced cellular GSH but did not lead to generation of ROI. Furthermore, cells remained viable up to 72 h. Analysis of subcellular fractions revealed complete loss of cytosolic and mitochondrial GSH within 4 h of EA treatment. In contrast, BSO-treated cells still maintained 100% GSH in the mitochondrial fraction for 4 h and 6% for 48 h. Mitochondrial complex II/IIi and IV activities were not significantly decreased up to 48 h of BSO treatment while EA treatment resulted in a complete loss of complex II/III activity and a 70% reduction of complex IV activity within 4 h. These findings suggest that mitochondrial GSH is critical for the maintenance of mitochondrial function and cellular viability.


Addiction Biology | 2005

Effects of MPEP on expression of food-, MDMA- or amphetamine-conditioned place preference in rats

Volker Herzig; Eleonora M. I. Capuani; Karl-Artur Kovar; Werner J. Schmidt

Recent studies have revealed the effectiveness of 2‐methyl‐6‐(phenylethynyl)pyridine (MPEP), a highly selective antagonist of metabotropic glutamate receptors subtype 5 (mGluR5), in conditioned drug reward. In a previous study we showed that MPEP blocks expression of context‐conditioned morphine‐ but not cocaine reward in the rat. The present study now examines the effectiveness of MPEP in the expression of context‐conditioned food, MDMA (‘ecstasy?) or amphetamine reward. Therefore, three groups of rats were conditioned either to food, MDMA or amphetamine in the conditioned place preference (CPP) paradigm. After conditioning, CPP expression and locomotion were determined simultaneously in the presence and absence of the respective reward (i.e. food or drug), or after application of 50?mg/kg MPEP (the dose that was most effective in reducing morphine CPP expression in our previous study). As a result, MPEP reduced locomotion in all groups. Furthermore, only expression of amphetamine CPP was inhibited by MPEP, while expression of food and MDMA CPP was not affected, suggesting that the MPEP‐induced inhibition of amphetamine CPP expression was not causally linked to the reduction of locomotion. Overall, we conclude that MPEP reduces expression of context‐conditioned amphetamine but not MDMA or food reward.


Neuroscience Letters | 2001

Changes in serotonin, dopamine and noradrenaline levels in striatum and nucleus accumbens after repeated administration of the abused drug MDMA in rats.

Andreas Mayerhofer; Karl-Artur Kovar; Werner J. Schmidt

The selective neurotoxic action of the abused drug 3,4-methylenedioxymethamphetamine (MDMA) on the serotonergic axons ascending from the dorsal raphe nucleus (DRN) is well known. The present study examined the long-term effects of subchronic MDMA treatment on rat brain tissue contents of catecholaminergic neurotransmitters. Two and four weeks after cessation of repeated MDMA treatment (ten consecutive days, 20 mg/kg/day), the tissue neurotransmitter concentrations were measured by means of electrochemical detected HPLC in several forebrain areas and DRN. We found reduced serotonin levels in the whole forebrain at both instants of time. In nucleus accumbens (NAC), the noradrenaline levels were also decreased, whereas dopamine levels were increased 4 weeks after treatment. It is concluded that MDMA causes changes of monoamine transmitter levels outlasting cessation of drug intake for at least 4 weeks. Decreased noradrenaline and/or serotonin may subsequently cause the augmentation of dopamine in NAC, a structure crucially involved in motivation circuits. With exception of transmitter alterations in the NAC, the post drug effects are opposite to the acute effects of MDMA and may underlie the psychiatric changes after MDMA intake in humans.


European Journal of Pharmaceutics and Biopharmaceutics | 2001

One hundred percent online identity check of pharmaceutical products by near-infrared spectroscopy on the packaging line.

Thorsten Herkert; Heino Prinz; Karl-Artur Kovar

To increase product safety of pharmaceuticals, a new near-infrared (NIR) method for the online identity check of pharmaceutical finished products was validated. The method comprises a new near-infrared device VisioNIR (Uhlmann VisioTec GmbH, Laupheim, Germany) and the appropriate evaluation statistics. The VisioNIR is applied to the packaging line and provides the possibility to perform a 100% product identity check at full line speed. The products were analyzed applying near-infrared spectroscopy (900-1700 nm) in reflectance mode. The scanned products were two widely used pharmaceuticals named Capsule A (containing 300 mg of paracetamol and 250 mg of chlorzoxazone) and Capsule B (containing 500 mg of paracetamol and 30 mg of codeine phosphate). In order to demonstrate the fitness of the VisioNIR the obtained data were compared with the data acquired by Foss NIRSystems 6500 spectrometer (NIRSystems, Silver Springs, MD). The results obtained by the VisioNIR evaluation statistics were compared with the results obtained by the commonly used principal component analysis. The advantages and the suitability of the method are discussed. In this new configuration NIR spectroscopy offers an excellent possibility for non-destructive 100% online quality control of pharmaceutical products.


Journal of Chromatography B: Biomedical Sciences and Applications | 1998

Quantitation of psilocin in human plasma by high-performance liquid chromatography and electrochemical detection: comparison of liquid-liquid extraction with automated on-line solid-phase extraction.

Hiltrud Lindenblatt; Edda Krämer; Petra Holzmann-Erens; Euphrosyne Gouzoulis-Mayfrank; Karl-Artur Kovar

Two modifications of the HPLC-ED method with respect to extraction procedure used have been developed for psilocin, the active metabolite of psilocybin, in human plasma using either liquid-liquid extraction (LLE) or automated on-line solid-phase extraction (on-line SPE). Each type of the sample preparation required a different HPLC system followed by electrochemical detection at 650 to 675 mV. The limit of quantitation of both modifications was 10 ng/ml psilocin. There was no significant difference observable between the LLE and the on-line SPE in terms of method standard deviation (LLE 1.82%, on-line SPE 1.13%) and the analytical results. However, the advantages of on-line SPE in addition to different selectivity were less manual effort, smaller plasma volumes of 400 microl (LLE 2 ml) and a recovery of psilocin in human plasma of nearly 100% (LLE 88%). In contrast to a previous procedure both methods were rapid, simple and reliable and yielded high plasma recoveries. They were used successfully in the quantitation of psilocin in plasma samples obtained from healthy volunteers after p.o. administration of 0.2 mg psilocybin per kg body mass. Plasma concentration curves and pharmacokinetic parameters were calculated.


Forensic Science International | 1999

Screening experiments of ecstasy street samples using near infrared spectroscopy.

Nicole Sondermann; Karl-Artur Kovar

Twelve different sets of confiscated ecstasy samples were analysed applying both near infrared spectroscopy in reflectance mode (1100-2500 nm) and high-performance liquid chromatography (HPLC). The sets showed a large variance in composition. A calibration data set was generated based on the theory of factorial designs. It contained 221 N-methyl-3,4-methylenedioxyamphetamine (MDMA) samples, 167 N-ethyl-3,4-methylenedioxyamphetamine (MDE), 111 amphetamine and 106 samples without a controlled substance, which will be called placebo samples thereafter. From this data set, PLS-1 models were calculated and were successfully applied for validation of various external laboratory test sets. The transferability of these results to confiscated tablets is demonstrated here. It is shown that differentiation into placebo, amphetamine and ecstasy samples is possible. Analysis of intact tablets is practicable. However, more reliable results are obtained from pulverised samples. This is due to ill-defined production procedures. The use of mathematically pretreated spectra improves the prediction quality of all the PLS-1 models studied. It is possible to improve discrimination between MDE and MDMA with the help of a second model based on raw spectra. Alternative strategies are briefly discussed.

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H. Auterhoff

University of Tübingen

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Renate Weber

University of Tübingen

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