Ketamine offers promising new therapeutic options for difficult-to-treat depression. The efficacy of treatment response, including ketamine, has been intricately linked to EEG measures of vigilance. This research investigated the interplay between intravenous ketamine and alterations in brain arousal, quantified through EEG vigilance assessments in two distinct cohorts of depressed patients (original dataset: n = 24; testing dataset: n = 24). Clinical response was defined as a decrease from baseline of >33% on the Montgomery-Åsberg Depression Rating Scale (MADRS) 24 h after infusion. EEG recordings were obtained pre-, start-, end- and 24 h post- infusion, and the resting EEG was automatically scored using the Vigilance Algorithm Leipzig (VIGALL). Relative to placebo (sodium chloride 0.9%), ketamine increased the amount of low-vigilance stage B1 at end-infusion. This increase in B1 was positively related to serum concentrations of ketamine, but not to norketamine, and was independent of clinical response. In contrast, treatment responders showed a distinct EEG pattern characterized by a decrease in high-vigilance stage A1 and an increase in low-vigilance B2/3, regardless of whether placebo or ketamine had been given. Furthermore, pretreatment EEG differed between responders and non-responders with responders showing a higher percentage of stage A1 (53% vs. 21%). The logistic regression fitted on the percent of A1 stages was able to predict treatment outcomes in the testing dataset with an area under the ROC curve of 0.7. Ketamine affects EEG vigilance in a distinct pattern observed only in responders. Consequently, the percentage of pretreatment stage A1 shows significant potential as a predictive biomarker of treatment response.Clinical Trials Registration: https://www.clinicaltrialsregister.eu/ctr-search/trial/2013-000952-17/CZ Registration number: EudraCT Number: 2013-000952-17.

• MeSH
• bdění MeSH
• depresivní porucha unipolární * farmakoterapie   MeSH
• elektroencefalografie MeSH
• ketamin * farmakologie   terapeutické užití   MeSH
• lidé MeSH
• mozek MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ketamin * MeSH

Ketamine is clinically used fast-acting antidepressant. Its metabolite hydroxynorketamine (HNK) shows a robust antidepressant effect in animal studies. It is unclear, how these chemically distinct compounds converge on similar neuronal effects. While KET acts mostly as N-methyl-d-aspartate receptor (NMDAR) antagonist, the molecular target of HNK remains enigmatic. Here, we show that KET and HNK converge on rapid inhibition of glutamate release by reducing the release competence of synaptic vesicles and induce nuclear translocation of pCREB that controls expression of neuroplasticity genes connected to KET- and HNK-mediated antidepressant action. Ro25-6981, a selective antagonist of GluN2B, mimics effect of KET indicating that GluN2B-containing NMDAR might mediate the presynaptic effect of KET. Selective antagonist of α7 nicotinic acetylcholine receptors (α7nAChRs) or genetic deletion of Chrna7, its pore-forming subunit, fully abolishes HNK-induced synaptic and nuclear regulations, but leaves KET-dependent cellular effects unaffected. Thus, KET or HNK-induced modulation of synaptic transmission and nuclear translocation of pCREB can be mediated by selective signaling via NMDAR or α7nAChRs, respectively. Due to the rapid metabolism of KET to HNK, it is conceivable that subsequent modulation of glutamatergic and cholinergic neurotransmission affects circuits in a cell-type-specific manner and contributes to the therapeutic potency of KET. This finding promotes further exploration of new combined medications for mood disorders.

• MeSH
• alfa7 nikotinové acetylcholinové receptory genetika   MeSH
• antidepresiva farmakologie   MeSH
• exprese genu MeSH
• ketamin * analogy a deriváty   farmakologie   MeSH
• kyselina aspartová MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• alfa7 nikotinové acetylcholinové receptory MeSH
• antidepresiva MeSH
• ketamin * MeSH
• kyselina aspartová MeSH

The present study aimed to examine a weakly electric fish Gnathonemus petersii (G. petersii) as a candidate model organism of glutamatergic theory of schizophrenia. The idea of G. petersii elevating the modeling of schizophrenia symptoms is based on the fish's electrolocation and electrocommunication abilities. Fish were exposed to the NMDA antagonist ketamine in two distinct series differing in the dose of ketamine. The main finding revealed ketamine-induced disruption of the relationship between electric signaling and behavior indicating impairment of fish navigation. Moreover, lower doses of ketamine significantly increased locomotion and erratic movement and higher doses of ketamine reduced the number of electric organ discharges indicating successful induction of positive schizophrenia-like symptoms and disruption of fish navigation. Additionally, a low dose of haloperidol was used to test the normalization of the positive symptoms to suggest a predictive validity of the model. However, although successfully induced, positive symptoms were not normalized using the low dose of haloperidol; hence, more doses of the typical antipsychotic haloperidol and probably also of a representative of atypical antipsychotic drugs need to be examined to confirm the predictive validity of the model.

• Klíčová slova
• Gnathonemus petersii, electrolocation, positive symptoms, schizophrenia model, weakly electric fish,
• MeSH
• elektrické ryby * MeSH
• haloperidol farmakologie   MeSH
• ketamin * farmakologie   MeSH
• lokomoce MeSH
• schizofrenie * chemicky indukované   farmakoterapie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• haloperidol MeSH
• ketamin * MeSH

Ketamine exerts anti-inflammatory, neuroprotective and neuroplastic activity, therefore it may counteract the neurotoxic processes underlying postoperative delirium. However, the majority of studies in this field failed. We identified several pharmacological reasons why these studies may have failed, together with suggestions of how to remediate them. Among them, the interaction with intravenous general anesthetics exerting the opposite effect on GABA interneurons than ketamine may be of principal importance. We suggest biomarkers which may elucidate the influence of this interaction on the different steps of neuroplastic pathways. We hypothesize that administering ketamine before or after general anesthesia could both prevent the interactions and strengthen the effect of ketamine by timing surgery within the climax of ketamine-induced neuroplastic changes or by stabilizing AMPA receptors. It is vital to deal with these questions because the protocols of ongoing studies are based again on the administration of ketamine during general anesthesia (the major identified pitfall).

• Klíčová slova
• Anesthesia, Benzodiazepines, Ketamine, Neuroplastic, Neuroprotective, Pharmacological interaction, Postoperative delirium,
• MeSH
• anestetika celková * MeSH
• anestetika disociativní MeSH
• anestetika intravenózní MeSH
• celková anestezie MeSH
• ketamin * terapeutické užití   MeSH
• lidé MeSH
• pooperační delirium * farmakoterapie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• anestetika celková * MeSH
• anestetika disociativní MeSH
• anestetika intravenózní MeSH
• ketamin * MeSH

Depression is disabling and highly prevalent. Intravenous (IV) ketamine displays rapid-onset antidepressant properties, but little is known regarding which patients are most likely to benefit, limiting personalized prescriptions. We identified randomized controlled trials of IV ketamine that recruited individuals with a relevant psychiatric diagnosis (e.g., unipolar or bipolar depression; post-traumatic stress disorder), included one or more control arms, did not provide any other study-administered treatment in conjunction with ketamine (although clinically prescribed concurrent treatments were allowable), and assessed outcome using either the Montgomery-Åsberg Depression Rating Scale or the Hamilton Rating Scale for Depression (HRSD-17). Individual patient-level data for at least one outcome was obtained from 17 of 25 eligible trials [pooled n = 809]. Rates of participant-level data availability across 33 moderators that were solicited from these 17 studies ranged from 10.8% to 100% (median = 55.6%). After data harmonization, moderators available in at least 40% of the dataset were tested sequentially, as well as with a data-driven, combined moderator approach. Robust main effects of ketamine on acute [~24-hours; β*(95% CI) = 0.58 (0.44, 0.72); p < 0.0001] and post-acute [~7 days; β*(95% CI) = 0.38 (0.23, 0.54); p < 0.0001] depression severity were observed. Two study-level moderators emerged as significant: ketamine effects (relative to placebo) were larger in studies that required a higher degree of previous treatment resistance to federal regulatory agency-approved antidepressant medications (≥2 failed trials) for study entry; and in studies that used a crossover design. A comprehensive data-driven search for combined moderators identified statistically significant, but modest and clinically uninformative, effects (effect size r ≤ 0.29, a small-medium effect). Ketamine robustly reduces depressive symptoms in a heterogeneous range of patients, with benefit relative to placebo even greater in patients more resistant to prior medications. In this largest effort to date to apply precision medicine approaches to ketamine treatment, no clinical or demographic patient-level features were detected that could be used to guide ketamine treatment decisions.Review Registration: PROSPERO Identifier: CRD42021235630.

• MeSH
• antidepresiva terapeutické užití   MeSH
• bipolární porucha * farmakoterapie   MeSH
• deprese farmakoterapie   MeSH
• intravenózní podání MeSH
• ketamin * terapeutické užití   MeSH
• lidé MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• metaanalýza MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• antidepresiva MeSH
• ketamin * MeSH

Tear production is an important factor in maintaining proper function of the cornea and conjunctiva. The purpose of this study was to determine the effects of bolus followed by infusion of fentanyl, lidocaine, and ketamine on tear production as measured by the Schirmer I Tear Test (STT-I) in dogs. A prospective, randomized, "double-blind" study was performed. A total of 55 healthy conscious client-owned dogs were included in the study. Dogs were randomly allocated to one of four groups and given intravenous fentanyl 0.005 mg kg-1 followed by 0.005 mg kg-1 hour-1 (FEN-group), ketamine 0.6 mg kg-1 followed by 0.6 mg kg-1 hour-1 (KET-group), lidocaine 1 mg kg-1 followed by 1 mg kg-1 hour-1 (LID-group), or saline 0.3 mL kg-1 followed by 2 mL kg-1 hour-1 (SAL-group). The STT-I was performed prior to (baseline) and again 30 minutes (T30) after initiation of drug administration. Data were expressed as the median (minimum - maximum) and analyzed by Wilcoxon and Steel-Dwass tests (P < .05). The STT-I values increased little but were statistically significant in the KET-group from 18 (14-23) to 19 (14-25) (P = .039) and in the LID-group from 21 (14-25) to 20 (17-29) (P = .027). At 30 minutes, STT-I values were significantly higher in LID-group 20 (17-29) than in FEN-group 18 (12-22) (P = .006). Fentanyl, ketamine, and lidocaine administered at the studied doses as a bolus and then followed by an infusion within 30 minutes in healthy conscious dogs demonstrated a clinically insignificant effect on tear production as measured by STT-I.

• Klíčová slova
• fentanyl, ketamine, lidocaine, tear production,
• MeSH
• fentanyl farmakologie   MeSH
• ketamin * farmakologie   MeSH
• lidokain farmakologie   MeSH
• prospektivní studie MeSH
• psi MeSH
• slzy MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• randomizované kontrolované studie veterinární MeSH
• Názvy látek
• fentanyl MeSH
• ketamin * MeSH
• lidokain MeSH

This determination of the mitochondrial effect of pharmacologically different antidepressants (agomelatine, ketamine and vortioxetine) was evaluated and quantified in vitro in pig brain-isolated mitochondria. We measured the activity of mitochondrial complexes, citrate synthase, malate dehydrogenase and monoamine oxidase, and the mitochondrial respiratory rate. Total hydrogen peroxide production and ATP production were assayed. The most potent inhibitor of all mitochondrial complexes and complex I-linked respiration was vortioxetine. Agomelatine and ketamine inhibited only complex IV activity. None of the drugs affected complex II-linked respiration, citrate synthase or malate dehydrogenase activity. Hydrogen peroxide production was mildly increased by agomelatine, which might contribute to increased oxidative damage and adverse effects at high drug concentrations. Vortioxetine significantly reduced hydrogen peroxide concentrations, which might suggest antioxidant mechanism activation. All tested antidepressants were partial MAO-A inhibitors, which might contribute to their antidepressant effect. We observed vortioxetine-induced MAO-B inhibition, which might be linked to decreased hydrogen peroxide formation and contribute to its procognitive and neuroprotective effects. Mitochondrial dysfunction could be linked to the adverse effects of vortioxetine, as vortioxetine is the most potent inhibitor of mitochondrial complexes and complex I-linked respiration. Clarifying the molecular interaction between drugs and mitochondria is important to fully understand their mechanism of action and the connection between their mechanisms and their therapeutic and/or adverse effects.

• Klíčová slova
• ATP, agomelatine, antidepressants, ketamine, mitochondrial respiration, monoamine oxidase, oxidative phosphorylation, reactive oxygen species, vortioxetine,
• MeSH
• antidepresiva farmakologie   MeSH
• citrátsynthasa MeSH
• ketamin * farmakologie   MeSH
• malátdehydrogenasa MeSH
• monoaminoxidasa MeSH
• peroxid vodíku MeSH
• prasata MeSH
• respirační komplex I MeSH
• vortioxetin farmakologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• agomelatine MeSH Prohlížeč
• antidepresiva MeSH
• citrátsynthasa MeSH
• ketamin * MeSH
• malátdehydrogenasa MeSH
• monoaminoxidasa MeSH
• peroxid vodíku MeSH
• respirační komplex I MeSH
• vortioxetin MeSH

OBJECTIVES: Different psychoactive substances are widely used in today's society. So far limited data are available on the use of psychedelics in the general population. The main aim of this study is to estimate the numbers of users of substances with psychedelic properties (classical psychedelics, cannabis, ecstasy, and ketamine) in the Czech Republic. METHODS: Data from two samples enrolled in representative cross-sectional questionnaire surveys in the Czech adult population in 2016 (n = 2,785) and 2018 (n = 1,665) were analysed. Prevalence rates were extrapolated to estimate numbers of current, i.e., last-year, users of psychedelics, and their socio-demographic profiles were compared with non-users and users of cannabis. RESULTS: An estimated 5-6% of the Czech adult population (350-430 thousand people) used classical psychedelics (LSD, psilocybin mushrooms, ayahuasca) in their lifetime, increasing up to 28-30% when cannabis is included (1.9-2.1 million users). Current use of classical psychedelics reached 0.7-1.9% (50-130 thousand people), and 9-11% (590-750 thousand users) when cannabis was included. Users of psychedelics were more often males, of younger age and single. CONCLUSIONS: No significant socio-demographic differences were found between users of classical psychedelics and recreational cannabis users, however, differences were significant when compared to non-users and users of other illicit drugs. Findings should further serve to inform drug policy and social and healthcare systems in respect to the use of psychedelics.

• Klíčová slova
• cannabis, epidemiology, hallucinogens, medical cannabis, psychedelics, substance use,
• MeSH
• Cannabis * MeSH
• dospělí MeSH
• halucinogeny * terapeutické užití   MeSH
• ketamin * MeSH
• lidé MeSH
• LSD MeSH
• poruchy spojené s užíváním psychoaktivních látek * epidemiologie   MeSH
• průřezové studie MeSH
• psilocybin MeSH
• zakázané drogy * MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Názvy látek
• halucinogeny * MeSH
• ketamin * MeSH
• LSD MeSH
• psilocybin MeSH
• zakázané drogy * MeSH

Ketamine, an N-methyl-D-aspartate antagonist, reduces pain by decreasing central sensitization and pain windup. However, chronic ketamine use can cause tolerance, dependency, impaired consciousness, urinary symptoms, and abdominal pain. This study aimed to investigate the effects of repeated ketamine injections and ketamine readministration after discontinuation in a rat model of neuropathic pain. To induce neuropathic pain, partial sciatic nerve ligation (PSNL) was performed in 15 male Wistar rats, and these animals were divided into three groups: PSNL (control), PSNL + ketamine 5 mg/kg (K5), and PSNL + ketamine 10 mg/kg (K10; n=5 each). Ketamine was injected intraperitoneally daily for 4 weeks, discontinued for 2 weeks, and then readministered for 1 week. Following PSNL, the mechanical withdrawal threshold was determined weekly using the Von Frey. The K10 group showed a significant increase in the mechanical withdrawal threshold, presented here as the target force (in g), at 21 and 28 days compared to the time point before ketamine injection (mean±SE, 276.0±24.0 vs. 21.6±2.7 and 300.0±0.0 vs. 21.6±2.7, respectively; P<0.01) and at 14, 21, and 28 days compared to the control group (108.2±51.2 vs. 2.7±1.3, 276.0±24.0 vs. 2.5±1.5, and 300.0±0.0 vs. 4.0±0.0, respectively; P<0.05). However, in the K10 group, the ketamine effects decreased significantly at 7 days after readministration compared to those after 28 days of repeated injections (P<0.05). In the K10 group, repeated ketamine injections showed a significant increase in antinociceptive effect for >2 weeks, but this ketamine effect decreased after drug readministration.

• MeSH
• hyperalgezie MeSH
• ketamin * farmakologie   MeSH
• krysa rodu Rattus MeSH
• měření bolesti MeSH
• nervus ischiadicus MeSH
• neuralgie * farmakoterapie   MeSH
• potkani Wistar MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ketamin * MeSH

BACKGROUND AND PURPOSE: Deschloroketamine (DCK), a structural analogue of ketamine, has recently emerged on the illicit drug market as a recreational drug with a modestly long duration of action. Despite it being widely used by recreational users, no systematic research on its effects has been performed to date. EXPERIMENTAL APPROACH: Pharmacokinetics, acute effects, and addictive potential in a series of behavioural tests in Wistar rats were performed following subcutaneous (s.c.) administration of DCK (5, 10, and 30 mg·kg-1 ) and its enantiomers S-DCK (10 mg·kg-1 ) and R-DCK (10 mg·kg-1 ). Additionally, activity at human N-methyl-d-aspartate (NMDA) receptors was also evaluated. KEY RESULTS: DCK rapidly crossed the blood brain barrier, with maximum brain levels achieved at 30 min and remaining high at 2 h after administration. Its antagonist activity at NMDA receptors is comparable to that of ketamine with S-DCK being more potent. DCK had stimulatory effects on locomotion, induced place preference, and robustly disrupted PPI. Locomotor stimulant effects tended to disappear more quickly than disruptive effects on PPI. S-DCK had more pronounced stimulatory properties than its R-enantiomer. However, the potency in disrupting PPI was comparable in both enantiomers. CONCLUSION AND IMPLICATIONS: DCK showed similar behavioural and addictive profiles and pharmacodynamics to ketamine, with S-DCK being in general more active. It has a slightly slower pharmacokinetic profile than ketamine, which is consistent with its reported longer duration of action. These findings have implications and significance for understanding the risks associated with illicit use of DCK.

• Klíčová slova
• NMDA receptor, deschloroketamine, enantiomers, locomotion, pharmacokinetics, prepulse inhibition,
• MeSH
• chování zvířat * účinky léků   MeSH
• ketamin * aplikace a dávkování   škodlivé účinky   analogy a deriváty   farmakokinetika   farmakologie   MeSH
• krysa rodu Rattus MeSH
• lokomoce * účinky léků   MeSH
• potkani Wistar MeSH
• receptory N-methyl-D-aspartátu metabolismus   MeSH
• zakázané drogy * škodlivé účinky   farmakokinetika   farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ketamin * MeSH
• receptory N-methyl-D-aspartátu MeSH
• zakázané drogy * MeSH