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Karel Valeš

4 papers in the library · 110 citations · publishing 2014-2025

Papers

The Effect of Psilocin on Memory Acquisition, Retrieval, and Consolidation in the Rat

Frontiers in Behavioral Neuroscience May 16, 2014 Lukáš Rambousek, Tomáš Páleníček, Karel Valeš et al. 55 citations

Psilocin, the main metabolite of psilocybin and an agonist at 5-HT2A receptors, dose-dependently impaired spatial learning and memory retrieval in rats but did not affect memory consolidation. In the Carousel maze, both 1 and 4 mg/kg doses significantly impaired acquisition, with the higher dose blocking learning even in a subsequent saline session. In the Morris water maze, only the 4 mg/kg dose disrupted reinforced retrieval; the lower dose had no effect. Neither dose impaired memory consolidation when injected post-training. These findings suggest that 5-HT2A receptor activation disrupts certain cognitive processes relevant to schizophrenia models, though the validity of such animal models remains questioned due to the complexity of human cognition.

Psilocin and ketamine microdosing: effects of subchronic intermittent microdoses in the elevated plus-maze in male Wistar rats

Behavioural Pharmacology March 13, 2018 Rachel R. Horsley, Tomáš Páleníček, Jan Kolin et al. 52 citations

Microdosing with hallucinogens such as ketamine and psilocin may produce mild anxiety-like effects rather than relief, according to a rat study. Over six days, rats received low or moderate doses of ketamine, psilocin, or saline on three occasions. Forty-eight hours after the final treatment, an elevated plus-maze test measured anxiety-related behaviors. Statistical effects were modest or borderline, but the pattern was most consistent with a mildly anxiogenic profile, significant at lower doses. Lower doses of both drugs produced comparable effects, as did higher doses, suggesting a possible common mechanism. The authors conclude that microdosing for therapeutic purposes might be counter-productive, though more research is needed.

Use of psychedelics in the Czech Republic: results of recent population surveys.

Central European journal of public health September 1, 2022 Pavla Chomynová, Rita Kočárová, Filip Kňažek et al. 2 citations

About 5-6% of Czech adults (350-430 thousand people) have ever used classical psychedelics such as LSD, psilocybin mushrooms, or ayahuasca, rising to 28-30% when cannabis is included (1.9-2.1 million users). Current (past-year) use of classical psychedelics is 0.7-1.9% (50-130 thousand people), and 9-11% (590-750 thousand users) when cannabis is included. Users of psychedelics are more often male, younger, and single. No significant socio-demographic differences appear between users of classical psychedelics and recreational cannabis users, but both groups differ from non-users and users of other illicit drugs.

Effects of Clozapine, Haloperidol, and the NMDA Antagonist Ketamine on Novel Object Recognition in Gnathonemus petersii: A New Possible Model for Schizophrenia Research

Fishes May 15, 2025 Petra Horká, Josefina Mavrogeni, Veronika Langová et al. 1 citation

The weakly electric fish Gnathonemus petersii preferred a familiar object over a novel one in the novel object recognition task, spending less time, moving a shorter distance, and emitting fewer electric organ discharges when exploring the novel object. Ketamine, an NMDA receptor antagonist, did not produce significant behavioral changes on its own, and no direct link was found between electric organ discharges and behavioral responses to ketamine or typical antipsychotics. However, when ketamine was combined with the atypical antipsychotic clozapine, the fish no longer distinguished between the original and new objects, suggesting the drug combination disrupted object recognition.