Psychopharmacology
January 1, 2013
Tomáš Páleníček, Michaela Fujáková, Martin Brunovský et al.
51 citations
The synthetic compound 2C-B produces a biphasic effect on movement in rats: initial inhibition followed by excitation, while amphetamine only causes hyperactivity. Both drugs disrupt prepulse inhibition of the acoustic startle reaction, a measure of sensory gating, but have opposite effects on the startle itself. 2C-B increases dopamine and decreases its metabolite DOPAC in the nucleus accumbens, a brain region linked to reward. Low doses of 2C-B reduce electrical brain activity and connectivity; a high dose first decreases then increases brain wave power and connectivity. Increases in theta and alpha brain waves correlate with heightened movement and dopamine levels. These results suggest 2C-B shares properties with hallucinogens, entactogens, and stimulants, and its dopamine effects may indicate psychotomimetic and addictive potential.
Pharmacology, biochemistry, and behavior
December 1, 2024
Lucie Olejníková-Ladislavová, Michaela Fujáková-Lipski, Klára Šíchová et al.
5 citations
Mescaline, a classical psychedelic, primarily acts on serotonin 5-HT2A/C receptors but also binds to 5-HT1A and 5-HT2B receptors. In adult male rats, the highest dose (100 mg/kg) caused hyperlocomotion, which was reversed by almost all antagonists tested. Sensorimotor gating deficits, measured as prepulse inhibition of acoustic startle, were selectively normalized by a 5-HT2A antagonist, while a 5-HT2C antagonist partially reversed deficits from lower doses. These findings indicate that mescaline's behavioral effects are mainly mediated by the 5-HT2A receptor subtype, with a lesser role for 5-HT2C receptors, and limited involvement of other subtypes.
Biological psychiatry global open science
September 1, 2025
Čestmír Vejmola, Klára Šíchová, Kateřina Syrová et al.
4 citations
Psilocin, the active compound in psychedelic mushrooms, impairs the ability to distinguish between static and moving images in both humans and rats. In a visual discrimination task, human participants and male rats were asked to judge whether an image was static or moving. Under psilocin, both species showed significant difficulty in this task. In humans, the impairment tracked psilocin plasma levels and self-reported hallucination intensity. In rats, psilocin selectively disrupted performance in a motion-based task but not a luminance-based task, suggesting a specific effect on motion perception. Decision time was also linked to discrimination impairment. This is the first evidence that rats experience visual distortions similar to those reported by humans, offering a model for studying altered visual perception in drug-induced and psychiatric conditions.
Pharmacological reports : PR
June 16, 2025
Tereza Klučková, Marek Nikolič, Filip Tylš et al.
4 citations
In healthy individuals, psilocybin produces lasting positive effects regardless of previous psychedelic experience, repeated use, setting, sex, or occupation. In a double-blind, placebo-controlled crossover study with 40 participants (20 females, mean age 38), each received two doses of psilocybin (0.26 mg/kg) at least 56 days apart. Acute effects were moderate on the Altered States of Consciousness Scales, with mostly pleasant or fluctuating experiences and only one unpleasant session; all sessions ended positively or neutrally. Long-term effects, assessed by the Persisting Effects Questionnaire, were positive across all domains with negligible negative effects. Peak experiences ending in a positive mood strongly predicted favorable long-term outcomes, while challenging experiences did not cause adverse outcomes. These findings support psilocybin's psychological safety and repeated use in clinical trials.
Frontiers in pharmacology
January 1, 2023
Kateřina Syrová, Klára Šíchová, Hynek Danda et al.
4 citations
2C-B-Fly-NBOMe, a new psychoactive substance related to the psychedelic entactogen 2C-B, was studied in adult male Wistar rats. After injection, peak drug levels in blood serum occurred at 30 minutes (28 ng/ml) and in brain tissue at 60 minutes (171 ng/g), with the compound still detectable in the brain after 8 hours. The drug dose-dependently reduced locomotor activity and strongly disrupted the acoustic startle response, with a weaker effect on prepulse inhibition. It did not cause significant changes in body temperature. The overall profile resembles that of 2C-B and other NBOMe substances, suggesting slow brain penetration and inhibitory effects on motor performance and sensorimotor gating.
Therapeutic advances in psychopharmacology
January 1, 2026
Veronika Andrashko, Tomáš Novák, Miloslav Kopecek et al.
Higher blood pressure during ketamine infusion was associated with better antidepressant response in people with depression. Among 39 patients who received a single intravenous dose of ketamine, those who responded at day 7 had significantly higher systolic and diastolic blood pressure during the infusion than nonresponders. Dissociation and psychotomimetic symptoms did not differ between responders and nonresponders. Concomitant antipsychotic medication was linked to worse antidepressant outcome and lower infusion-related blood pressure. Plasma levels of ketamine or norketamine did not correlate with blood pressure, dissociative symptoms, or psychotomimetic effects.
bioRxiv Preprint Server
August 28, 2024
Lucie Olejníková-Ladislavová, Michaela Fujáková-Lipski, Klára Šíchová et al.
preprint
Mescaline, a classical psychedelic with a phenylethylamine structure, primarily acts on serotonin 5-HT2A/C receptors but also binds to 5-HT1A and 5-HT2B receptors. Although it was the first psychedelic ever isolated and synthesized, the precise role of these different serotonin receptor subtypes in its behavioral pharmacology remains not fully understood.
IBRO Neuroscience Reports
November 6, 2023
Tomáš Páleníček, Tereza Klučková, Marek Nikolič et al.
The study examined how the subjective experiences (phenomenology) induced by psilocybin, a psychedelic drug being tested as a rapid-acting antidepressant, relate to long-term changes in mood, spirituality, and relationships with self, life, and others. In healthy volunteers, positive aspects of the psychedelic experience were associated with beneficial long-term outcomes, while fearful aspects were linked to negative long-term outcomes. The findings suggest that the quality of the subjective experience during psilocybin use may influence its lasting psychological effects.
Frontiers in psychology
January 1, 2017
Marek Havlík, Eva Kozáková, Jiří Horáček
This review addresses two central questions about consciousness: the 'how' (neural correlates and mechanisms) and the 'why' (the hard problem of why conscious experience exists at all). The authors argue that while the hard problem will likely never fully disappear, its significance may diminish as empirical research advances. They predict that future work will be guided by a unifying brain theory—predictive coding—which must explain both perceptual consciousness and conscious mind-wandering to succeed. Such a theory could clarify the function of conscious experience, thereby reducing the weight of the hard problem.
Neuroscience and biobehavioral reviews
July 1, 2008
Věra Bubeníková-valešová, Jiří Horáček, Monika Vrajová et al.
Research using non-competitive NMDA receptor antagonists—phencyclidine, ketamine, and dizocilpine—produces behavioral changes in humans and rats that resemble schizophrenia symptoms. Acute and chronic administration models show phenomenological validity and help test potential antipsychotic drugs. However, schizophrenia's pathophysiology remains unexplained. The neurodevelopmental model suggests that early-life NMDA receptor antagonism increases apoptosis or alters glutamatergic receptor function during central nervous system development, leading to psychosis that often emerges only in adulthood. Chronic antagonist administration triggers adaptation mechanisms that match findings in schizophrenia patients, making this model useful for studying the disease's pathophysiology.