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Kristýna Štefková

5 papers in the library · 143 citations · publishing 2017-2022

Papers

Pharmacokinetic, Ambulatory, and Hyperthermic Effects of 3,4-Methylenedioxy-N-Methylcathinone (Methylone) in Rats

Frontiers in Psychiatry November 17, 2017 Kristýna Štefková, Monika Židková, Rachel R. Horsley et al. 82 citations

Methylone, a synthetic cathinone analog of ecstasy, is marketed as relatively safe but has caused fatalities from hyperthermia, serotonin syndrome, and multi-organ failure. In adolescent male Wistar rats, methylone (5, 10, 20 mg/kg subcutaneously) dose-dependently increased locomotion, reduced time in the open field center at 20 mg/kg, and induced stereotyped circling; its metabolite nor-methylone showed similar behavioral potency. Both drugs peaked in serum and brain at 30 minutes, with a serum-to-brain ratio of 1:7.97. Methylone also caused hyperthermia, more pronounced in group-housed rats, and 40 mg/kg was lethal to some animals. The findings suggest methylone acts like MDMA or amphetamine but with higher toxicity, posing risks of serotonin syndrome, especially in crowded settings.

Mephedrone (4-Methylmethcathinone): Acute Behavioral Effects, Hyperthermic, and Pharmacokinetic Profile in Rats

Frontiers in Psychiatry January 10, 2018 Klára Šíchová, Nikola Pinterová, Monika Židková et al. 28 citations

Mephedrone (MEPH) and its primary metabolite nor-mephedrone (nor-MEPH) were detected in the serum, brain, lungs, and liver of male Wistar rats, with the highest levels found in lungs. Maximum concentrations occurred at 30 minutes, and nor-MEPH levels exceeded those of the parent drug at 2 and 4 hours. Both drugs increased locomotion and altered its spatial distribution in a dose-dependent, rapid, and short-lasting manner, without disrupting prepulse inhibition. Behavioral effects disappeared within 40 minutes, but MEPH-induced rectal temperature elevations persisted for 3 hours even in singly housed rats, suggesting a dissociation between behavioral and hyperthermic effects that may contribute to prolonged somatic toxicity.

Naphyrone (naphthylpyrovalerone): Pharmacokinetics, behavioural effects and thermoregulation in Wistar rats

Addiction Biology May 7, 2020 Nikola Pinterová, Rachel R. Horsley, Hynek Danda et al. 13 citations

Naphyrone, a synthetic cathinone similar to pyrovalerone, potently blocks monoamine transporters and produces stimulant and entactogen-like effects. In male Wistar rats, a single subcutaneous dose of 1 mg/kg reached peak concentrations in blood and tissues within 30 minutes, with prolonged elevation in the brain relative to serum. A higher dose of 20 mg/kg caused modest increases in body temperature and lasting hyperactivity in an open field test, while transiently improving sensorimotor gating as measured by prepulse inhibition. No acute toxicity was observed. The drug crosses the blood-brain barrier rapidly and is eliminated slowly, with effects matching its pharmacokinetics. Harm-reduction guidance should follow that for other stimulants and cathinones.

Synthesis and identification of deschloroketamine metabolites in rats' urine and a quantification method for deschloroketamine and metabolites in rats' serum and brain tissue using liquid chromatography tandem mass spectrometry

Drug Testing and Analysis October 31, 2019 Kateřina Hájková, Bronislav Jurásek, Jan Čejka et al. 12 citations

Deschloroketamine, a ketamine analog sold illicitly since 2015 and sometimes misrepresented as ketamine, has potential antidepressant properties. A metabolomics study used liquid chromatography–high-resolution mass spectrometry and a validated multiple reaction monitoring method to track its metabolites in urine, serum, and brain tissue. Key metabolites—trans-dihydrodeschloroketamine, cis- and trans-dihydronordeschloroketamine, and nordeschloroketamine—were synthesized and used as standards. In serum, nordeschloroketamine and deschloroketamine concentrations ranged from 0.5 to 860 ng/mL; in brain tissue, they ranged from 0.5 to 4700 ng/g. The quantification methods showed intra-day accuracy of 80–125% and precision averaging 3–7%.

Pharmacokinetics, systemic toxicity, thermoregulation and acute behavioural effects of 25CN‐NBOMe

Addiction Biology August 4, 2022 Klára Šíchová, Kateřina Syrová, Edita Kofroňová et al. 8 citations

25CN-NBOMe, a substance related to LSD, readily crosses the blood-brain barrier in rats. After a 5 mg/kg dose, drug concentration peaked in blood and brain at 1 hour, with half-lives of 1.88 and 2.28 hours. The drug is classified as toxicity category 3, with a lethal dose of 300 mg/kg and an estimated LD50 of 200 mg/kg. Histological findings suggest acute cardiovascular arrest from malignant arrhythmia at lethal doses. A 5 mg/kg dose reduced body temperature in individually housed rats. Lower doses (0.2 and 1 mg/kg) reduced locomotor activity and increased anxiety, while 5 mg/kg also impaired sensorimotor gating. The drug's behavioral effects are comparable to other NBOMes.