Search Results (43)

The bidirectional relationship between epilepsy and depression illustrates shared neurobiological mechanisms of neuroinflammation, hypothalamic–pituitary–adrenal axis dysregulation, and glutamatergic dysfunction. Depression is present in 20–55% of people with epilepsy, far greater than in the general population, while depression doubles epilepsy risk 2.5-fold, indicating shared pathophysiology. Neuroinflammatory mediators (interleukin-6, tumor necrosis factor alpha, high-mobility group box 1) establish a vicious cycle: seizures exacerbate inflammation and mood disruption, and stress lowers seizure thresholds. Hippocampal damage and cortisol toxicity also link these disorders, with early life stress imprinting lifelong risk via epigenetic alteration. Genetic studies identify pleiotropic genes (brain-derived neurotrophic factor) that regulate synaptic plasticity, serotonin activity, and immune responses. New treatments target shared pathways: ketamine and AMPAkines normalize glutamate tone; mGluR5 antagonists attenuate hyperexcitability and inflammation; DNA methyltransferase inhibitors reverse aberrant DNA methylation; and probiotics manipulate the gut–brain axis by boosting neuroprotective metabolites like butyrate. Despite challenges—transient effects, precision dosing, and blood–brain barrier penetration—these advances constitute a paradigm shift toward mechanistic repair rather than symptom management. The way forward includes clustered regularly interspaced short palindromic repeats (CRISPR)-based epigenome editing, biomarker-led therapies, and combination approaches (e.g., ketamine and probiotics). Such comorbidity needs to be managed holistically through integrated neuropsychiatry care, offering hope to patients with treatment-refractory symptoms. Full article

Objectives: (R)-ketamine hydrochloride injection is a novel, rapid-acting antidepressant for the treatment of treatment-resistant depression. The aim of this study was to assess the pharmacokinetics, safety, and tolerability of (R)-ketamine hydrochloride injection in healthy Chinese subjects following ascending single intravenous doses ranging from 10.0 mg to 180 mg. Methods: This randomized, double-blind, placebo-controlled study was conducted in 50 healthy male and female Chinese subjects after single ascending doses of (R)-ketamine hydrochloride injection (10.0, 30.0, 60.0, 120, and 180 mg). Ten subjects (including two subjects treated with a placebo) were included in each dose cohort. Pharmacokinetic characteristics, safety, and tolerability profiles of the study drug were evaluated. Results: After the intravenous doses administered from 10.0 mg to 180 mg of (R)-ketamine hydrochloride injection to the subjects, the C_max and AUC values for both (R)-ketamine and its metabolite (R)-norketamine in the subjects increased approximately proportionally to the doses. The average peak plasma concentration levels at the five dose cohorts ranged from 56.0 to 1424 ng/mL and 27.7 to 491 ng/mL for (R)-ketamine and (R)-norketamine, respectively. The adverse events of (R)-ketamine hydrochloride injection were temporary and recovered spontaneously without treatment. Conclusions: In summary, (R)-ketamine hydrochloride injection was safe and well tolerated in healthy Chinese subjects. The clinical study results laid a foundation for the further clinical studies of (R)-ketamine hydrochloride injection in patients. Full article

Ketamine and esketamine are two closely related compounds with fast-acting antidepressant properties that have reshaped the treatment landscape for individuals with treatment-resistant depression (TRD). Originally developed as anesthetic agents, both have since demonstrated rapid and robust antidepressant effects in patients who have not responded to conventional treatments such as selective serotonin reuptake inhibitors (SSRIs) or cognitive behavioral therapy. This narrative review synthesizes evidence on their pharmacology, mechanisms of action, clinical efficacy, safety profiles, and regulatory considerations, with a particular focus on their neuroplastic effects. While ketamine is a racemic mixture composed of equal parts R- and S-enantiomers, esketamine consists solely of the S-enantiomer and has been approved for intranasal use by the FDA and EMA for TRD. These agents have been shown to produce symptom relief within hours of administration—an unprecedented effect in psychiatric pharmacology. This rapid onset is particularly valuable in managing suicidal ideation, offering potential lifesaving benefits in acute settings. Furthermore, ketamine and esketamine’s influence on synaptic plasticity, brain-derived neurotrophic factor (BDNF), and glutamate transmission provides insights into novel therapeutic targets beyond monoaminergic systems. This review incorporates recent real-world findings and peer-reviewed literature to contextualize the clinical use of these agents in modern psychiatry, bridging experimental research with practical application. Full article

Background/Objectives: Depression ranks among the most prevalent mental health conditions globally, marked by a variety of symptoms that frequently cause significant emotional distress and impairment in individuals, alongside a high recurrence rate. The predominant approach to treating depression revolves around monoamine theory, utilizing SSRIs and SNRIs, with Esketamine emerging as a supplementary option in recent times. Nevertheless, there is a growing focus on exploring the relationship between inflammation and depression, revealing a strong correlation between the two. This insight prompts consideration of the anti-inflammatory properties of current antidepressants in their therapeutic application. Methods: A systematic literature search was conducted using the PubMed database to identify randomized controlled trials (RCTs) and clinical trials (CTs) that assessed the in vivo anti-inflammatory effects of SSRIs (fluoxetine, escitalopram, sertraline, and paroxetine), the SNRI venlafaxine, and esketamine/ketamine in human subjects undergoing treatment for depression. The included studies were evaluated based on changes in levels of pro-inflammatory and anti-inflammatory markers in response to the antidepressant treatments. Results: SSRIs, SNRIs, esketamine, and ketamine (a racemic mixture of S- and R-ketamine not formally approved for the treatment of depression) exhibit anti-inflammatory effects through diverse mechanisms, such as reducing pro-inflammatory cytokines or enhancing anti-inflammatory cytokines in serum or within specific brain regions like the hippocampus and prefrontal cortex. These actions are mediated through various inflammatory pathways, including nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), the brain Nod-like receptor pyrin-containing 3 (NLRP3) inflammasome, the glutamatergic system, the gut–brain axis, the hypothalamic–pituitary axis, impaired neuroplasticity, and the kynurenine pathway. Conclusions: In summary, SSRIs, SNRIs, esketamine, and ketamine exert an anti-inflammatory role alongside their antidepressant effects via these intricate mechanisms. Full article

Despite affecting millions worldwide, major depressive disorder (MDD) remains a therapeutic challenge, with approximately one-third of patients failing to respond to standard treatments. The need for innovative, molecularly driven therapies has turned attention to ketamine and its enantiomers. While S-ketamine is clinically approved for treatment-resistant depression (TRD), it has various psychoactive side effects and potential for abuse. Hence, it is necessary to identify alternative compounds, such as R-ketamine, and their metabolites (e.g., 2S,6S-hydroxynorketamine and 2R,6R-hydroxynorketamine, collectively referred to as HNKs). Emerging evidence suggests that the pathophysiology of MDD involves two processes regulated by the unfolded protein response (UPR): endoplasmic reticulum (ER) stress and neuroinflammation. As such, they represent promising therapeutic targets. The study provides the first direct comparison of ketamine enantiomers and their metabolites in modulating ER stress and inflammatory signaling in human microglial cells (HMC3), which play key roles in neuroimmune communication. Both S-ketamine and R-ketamine, along with their metabolites, significantly reduced both the expression and protein levels of CHOP and GRP78—two critical UPR components—under tunicamycin-induced ER stress conditions. Additionally, the compounds significantly decreased IL-6 levels and, to a lesser extent, IL-8 levels in lipopolysaccharide (LPS)-stimulated microglia, indicating anti-inflammatory potential. Taken together, these findings highlight a novel glia-targeted mechanism by which ketamine and its metabolites modulate ER stress and neuroinflammation. CHOP and GRP78 appear to be stress-responsive molecular markers within the UPR pathway. These results justify further in vivo validation and support the development of antidepressants with fewer psychoactive effects. Full article

Background/objectives: Common carotid artery occlusion can cause oxidant and inflammatory damage to the optic nerve. In this study, the effect of sunitinib was investigated, the antioxidant and anti-inflammatory properties of which have been previously reported and shown to be protective in I/R injury and in preventing bilateral optic nerve ischemia–reperfusion (I/R) injuries after unilateral common carotid artery ligation in rats. Methods: In this study, 18 Albino Wistar male rats were divided into SG (sham-operated), CCU (clamping and unclamping), and SCCU (sunitinib + clamping and unclamping) groups. One hour before the surgical procedures, sunitinib (25 mg/kg, oral) was given to SCCU rats. Anesthesia was induced with ketamine (60 mg/kg, ip) and sevoflurane. The right common carotid arteries of all rats were accessed under anesthesia. While the skin opened in SG rats was closed with sutures, the right common carotid arteries of CCU and SCCU rats were clipped, and an ischemia period was created for 10 min. Then, reperfusion (6 h) was achieved by unclipping. After euthanasia with ketamine (120 mg/kg, intraperitoneally), the right and left optic nerves of the rats were removed and examined biochemically and histopathologically. Results: Malondialdehyde, tumor necrosis factor α, interleukin-1β, and interleukin-6 were increased, and total glutathione levels had decreased in both ipsilateral and contralateral optic nerves (p < 0.05). These changes were more prominent on the ipsilateral side. Similarly, histopathological damage was observed to be more on the ipsilateral side (p < 0.05). Biochemical and histopathological changes were significantly suppressed in rats receiving sunitinib treatment (p < 0.05). Conclusions: Sunitinib may protect optic nerve tissue against I/R injury by reducing oxidative stress and inflammation. Full article

Besides the well-known hallucinogenic ketamine, various novel ketamine derivatives are available on the illicit drug market, sold as designer drugs. Minor chemical changes to the parent compound aim to circumvent existing narcotic drug laws while mimicking the effects of the original substance. Ketamine and some of its derivatives possess a chiral centre and therefore exist as two enantiomers. While differences in the effects of S- and R-ketamine are well studied, this is not the case for ketamine derivatives. Therefore, the development and adaptation of suitable enantioseparation methods for those compounds is important to face the problems of the constantly changing drug market. In this study, different chiral separation methods for capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) were tested on 11 ketamine derivatives. Some of them were enantioseparated for the first time due to their novelty. All compounds were at least partially separated on both instruments. HPLC separations were conducted using four different polysaccharide-based chiral stationary phases. Furthermore, an optical rotation detector coupled to the HPLC enabled the determination of the enantiomer elution order. In CE analysis, enantioseparation was achieved using 2% (w/v) acetyl-β-cyclodextrin or carboxymethyl- β-cyclodextrin in 10 mM di-sodium hydrogen phosphate as the background electrolyte in capillary electrophoresis. Full article

Background/Objectives: Recent studies have investigated the effects of ketamine on fear memory in animals. However, it is unclear if ketamine might affect avoidance memory and emotional behaviors concomitantly. In this study, we compared the effects of (R,S)- and (S)-ketamine in modulating avoidance responses, depression- and anxiety-related behaviors in stressed mice. Methods: Mice were previously exposed to inescapable footshock stress, and 24 h later, they were trained in the active avoidance task. (R,S)-ketamine or (S)-isomer was administered 1 h prior to re-exposition to the active avoidance task. Three hours after drug administration, mice were tested in the tail suspension, followed by the open field test. Results: Neither form of ketamine affected avoidance memory retrieval, while (S)-ketamine, and tangentially, (R,S) reduced avoidance responses during re-exposition to aversive stimulus. In the tail suspension test, (R,S)- and (S)-ketamine equally evoked antidepressant effects. In the open field test, the racemic mixture, but not (S)-ketamine, induced anxiolytic actions. Conclusions: These findings reinforce the therapeutic potential of ketamine for the treatment of stress-related disorders, with (R,S)-ketamine being more effective in simultaneously inducing antidepressant and anxiolytic responses and reducing avoidance responses in stressed mice. Full article

Background and Objectives: Ischemia-reperfusion (I/R) injury is a process in which impaired perfusion is restored by restoring blood flow and tissue recirculation. Nanomedicine uses cutting-edge technologies that emerge from interdisciplinary influences. In the literature, there are very few in vivo and in vitro studies on how cerium oxide (CeO₂) affects systemic anti-inflammatory response and inflammation. Therefore, in our study, we aimed to investigate whether CeO₂ administration has a protective effect against myocardial I/R injury in the liver and kidneys. Materials and Methods: Twenty-four rats were randomly divided into four groups after obtaining approval from an ethics committee. A control (group C), cerium oxide (group CO), IR (group IR), and Cerium oxide-IR (CO-IR group) groups were formed. Intraperitoneal CeO₂ was administered at a dose of 0.5 mg/kg 30 min before left thoracotomy and left main coronary (LAD) ligation, and myocardial muscle ischemia was induced for 30 min. After LAD ligation was removed, reperfusion was performed for 120 min. All rats were euthanized using ketamine, and blood was collected. Liver and kidney tissue samples were evaluated histopathologically. Serum AST (aspartate aminotransferase), ALT (alanine aminotransaminase), GGT (gamma-glutamyl transferase), glucose, TOS (Total Oxidant Status), and TAS (Total Antioxidant Status) levels were also measured. Results: Necrotic cell and mononuclear cell infiltration in the liver parenchyma of rats in the IR group was observed to be significantly increased compared to the other groups. Hepatocyte degeneration was greater in the IR group compared to groups C and CO. Vascular vacuolization and hypertrophy, tubular degeneration, and necrosis were increased in the kidney tissue of the IR group compared to the other groups. Tubular dilatation was significantly higher in the IR group than in the C and CO groups. TOS was significantly higher in all groups than in the IR group (p < 0.0001, p < 0.0001, and p = 0.006, respectively). However, TAS level was lower in the IR group than in the other groups (p = 0.002, p = 0.020, and p = 0.031, respectively). Renal and liver histopathological findings decreased significantly in the CO-IR group compared to the IR group. A decrease in the TOS level and an increase in the TAS level were found compared to the IR group. The AST, ALT, GGT, and Glucose levels are shown. Conclusions: CeO₂ administered before ischemia-reperfusion reduced oxidative stress and ameliorated IR-induced damage in distant organs. We suggest that CeO₂ exerts protective effects in the myocardial IR model. Full article

The aim of this retrospective clinical study was to compare the combinations of ketamine/diazepam (KD group) and tiletamine/zolazepam (TZ group) for the induction of general anaesthesia in horses undergoing elective surgery. The data from the clinical and the anaesthetic records of 138 horses from 2021 to 2023 were evaluated, and the horses were divided in two groups: KD (n = 60) and TZ (n = 72). The horses were premedicated with romifidine and methadone IV; anaesthesia was induced with ketamine/diazepam for the KD group and tiletamine/zolazepam for the TZ group and was maintained with isoflurane and a constant rate infusion of romifidine. The data encompassed sex and neuter status, age, breed, weight, American Society of Anaesthesiologists physical status, type of surgical procedure performed under anaesthesia, induction time, induction score, surgery time, recovery time, and the recovery score using a descriptive scale. Baseline heart rate (HR), intraoperative HR, baseline respiratory rate (fR), intraoperative fR, mean arterial pressure (MAP), oxygen saturation (SpO₂), and fraction of expired isoflurane (F_E’Iso) were also recorded. The induction time was significantly longer (p = 0.004) in the TZ group (60 (40–120)) as compared to the KD group (50 (30–120)). Recovery time was also significantly longer (p ≤ 0.001) in the TZ group (46.5 (15–125)) as compared to the KD group (30 (5–105)). These findings suggested that, in adult horses undergoing elective surgery, TZ could be considered a valid alternative to KD for the induction of general anaesthesia. Additional experimental studies comparing the two induction regimens and their pharmacokinetic and pharmacodynamic characteristics are needed. Full article

Background/Objectives: This study evaluates the applicability of a comprehensive two-dimensional gas chromatography−flame ionisation detection (GC×GC−FID) approach for the simultaneous determination of 12 underivatised psychoactive drugs, including new psychoactive substances, that comprised of amphetamine, methamphetamine, mephedrone, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, α-pyrrolidinovalerophenone, n-ethylpentylone (ephylone), norketamine, ketamine, 3,4-methylenedioxypyrovalerone, methadone, and cocaine. Methods: Separation was effected using a non-polar first dimension (¹D) and a polar second dimension (²D) column, demonstrating an improved separation of drug compounds compared to a polar/non-polar column configuration. Interference-free baseline separation of all psychoactive compounds in a urine matrix was achieved within 8 min. The GC×GC−FID method was validated according to the guidelines defined by Standard Practices for Method Validation in Forensic Toxicology. Results: The calibration curves for the 12 psychoactive drugs were well correlated (r² > 0.99) within the concentration ranges of 50–1500 ng mL⁻¹. Detection limits of 10–20 ng mL⁻¹ were obtained, and good repeatability and reproducibility (CV < 11.4%) were attained for retention times and peak areas. Method recoveries for the small-scale solvent extraction procedure ranged from 96.9 to 114.5%, and bias was between −3.1% and 14.5%. Conclusions: The validated approach was successfully applied for the determination of these illicit compounds in spiked urine samples of different concentrations, highlighting its potential for rapid forensic drug screening. Full article

Research over the past years has compared the enantiomers (S)-ketamine (esketamine) and (R)-ketamine (arketamine) of the previously known racemic mixture called ketamine (R/S-ketamine). Esketamine has been found to be more potent, offering three times stronger analgesic effects and 1.5 times greater anesthetic efficacy than arketamine. It provides smoother anesthesia with fewer side effects and is widely used in clinical settings due to its neuroprotective, bronchodilatory, and antiepileptic properties. Approved by the FDA and EMA in 2019, esketamine is currently used alongside SSRIs or SNRIs for treatment-resistant depression (TRD). On the other hand, arketamine has shown potential for treating neurological disorders such as Alzheimer’s, Parkinson’s, and multiple sclerosis, offering possible antidepressant effects and anti-inflammatory benefits. While esketamine is already in clinical use, arketamine’s future depends on further research to address its safety, efficacy, and optimal dosing. Both enantiomers hold significant clinical value, with esketamine excelling in anesthesia, and arketamine showing promise in neurological and psychiatric treatments. Full article

Opioids effectively manage perioperative pain but have numerous adverse effects. Opioid-free anesthesia (OFA) eliminates intraoperative opioid use; however, evidence for its use in video-assisted thoracoscopic surgery (VATS) is limited. This study assessed the effect of OFA using ketamine in VATS patients compared to opioid-sparing anesthesia (OSA). A total of 91 patients undergoing VATS lobectomy or segmentectomy were randomized to either the OFA group (ketamine) or the OSA group (remifentanil). The primary outcome was the quality of recovery (QoR) on postoperative day (POD) 1, measured with the QoR-40 questionnaire. Secondary outcomes included postoperative pain scores and adverse events. Both groups had comparable baseline and surgical characteristics. On POD 1, the QoR-40 score was higher in the OFA group than in the OSA group (164.3 ± 10.8 vs. 158.7 ± 10.6; mean difference: 5.6, 95% CI: 1.1, 10.0; p = 0.015), though this did not meet the pre-specified minimal clinically important difference of 6.3. The visual analog scale score was lower in the OFA group as compared to the OSA group at 0–1 h (4.2 ± 2.3 vs. 6.2 ± 2.1; p < 0.001) and 1–4 h after surgery (3.4 ± 1.8 vs. 4.6 ± 1.9; p = 0.003). The OFA group had a lower incidence of PONV (2 [4.4%] vs. 9 [19.6%]; p = 0.049) and postoperative shivering (4 [8.9%] vs. 13 [28.3%]; p = 0.030) than the OSA group at 0–1 h after surgery. Using OFA with ketamine proved feasible, as indicated by the stable intraoperative hemodynamics and absence of intraoperative awareness. Patients undergoing VATS with OFA using ketamine showed a statistically significant, but clinically insignificant, QoR improvement compared to those receiving OSA with remifentanil. Full article

NMDA receptor antagonists have potential for therapeutics in neurological and psychiatric diseases, including neurodegenerative diseases, epilepsy, traumatic brain injury, substance abuse disorder (SUD), and major depressive disorder (MDD). (S)-ketamine was the first of a novel class of antidepressants, rapid-acting antidepressants, to be approved for medical use. The stereoisomer, (R)-ketamine (arketamine), is currently under development for treatment-resistant depression (TRD). The compound has demonstrated efficacy in multiple animal models. Two clinical studies disclosed efficacy in TRD and bipolar depression. A study by the drug sponsor recently failed to reach a priori clinical endpoints but post hoc analysis revealed efficacy. The clinical value of (R)-ketamine is supported by experimental data in humans and rodents, showing that it is less sedating, does not produce marked psychotomimetic or dissociative effects, has less abuse potential than (S)-ketamine, and produces efficacy in animal models of a range of neurological and psychiatric disorders. The mechanisms of action of the antidepressant effects of (R)-ketamine are hypothesized to be due to NMDA receptor antagonism and/or non-NMDA receptor mechanisms. We suggest that further clinical experimentation with (R)-ketamine will create novel and improved medicines for some of the neurological and psychiatric disorders that are underserved by current medications. Full article

This study investigates the combined effects of the neuropeptide Y Y1 receptor (NPY1R) agonist [Leu31-Pro34]NPY at a dose of 132 µg and Ketamine at 10 mg/Kg on cognitive functions and neuronal proliferation, against a backdrop where neurodegenerative diseases present an escalating challenge to global health systems. Utilizing male Sprague-Dawley rats in a physiological model, this research employed a single-dose administration of these compounds and assessed their impact 24 h after treatment on object-in-place memory tasks, alongside cellular proliferation within the dorsal hippocampus dentate gyrus. Methods such as the in situ proximity ligation assay and immunohistochemistry for proliferating a cell nuclear antigen (PCNA) and doublecortin (DCX) were utilized. The results demonstrated that co-administration significantly enhanced memory consolidation and increased neuronal proliferation, specifically neuroblasts, without affecting quiescent neural progenitors and astrocytes. These effects were mediated by the potential formation of NPY1R-TrkB heteroreceptor complexes, as suggested by receptor co-localization studies, although further investigation is required to conclusively prove this interaction. The findings also highlighted the pivotal role of brain-derived neurotrophic factor (BDNF) in mediating these effects. In conclusion, this study presents a promising avenue for enhancing cognitive functions and neuronal proliferation through the synergistic action of the NPY1R agonist and Ketamine, potentially via NPY1R-TrkB heteroreceptor complex formation, offering new insights into therapeutic strategies for neurodegenerative diseases. Full article