Search Results (240)

Background/Objective: A substantial proportion of patients with obsessive–compulsive disorder (OCD) does not respond adequately to first-line treatments such as selective serotonin reuptake inhibitors and cognitive-behavioral therapy. OCD has traditionally been conceptualized as a serotonergic disorder. However, emerging evidence suggests that glutamatergic dysfunction plays an important role. Ketamine and esketamine are NMDA receptor antagonists with rapid antidepressant effects and have therefore attracted interest as potential treatments for OCD. This scoping review aims to map and synthesize the existing preclinical and clinical evidence regarding the therapeutic potential of ketamine and esketamine in OCD. Methods: A scoping review methodology based on the Arksey and O’Malley framework and Joanna Briggs Institute guidance was applied. Searches were conducted in PubMed, Scopus, and Web of Science. Studies that examined ketamine or esketamine in OCD populations or relevant experimental models were included. Results: Twenty-one studies met the inclusion criteria, of which five were preclinical studies and sixteen were clinical investigations. Preclinical evidence suggests that ketamine and esketamine improve compulsive-like behaviors. Clinical studies suggest that ketamine can produce rapid reductions in obsessive symptoms, though results remain inconsistent. Most trials evaluated single administrations, while limited evidence suggests that repeated dosing strategies may provide greater clinical benefit. Conclusions: Ketamine and esketamine show promise as rapid acting interventions for OCD, particularly in treatment refractory cases. However, current evidence remains preliminary and heterogeneous. Future research should prioritize adequately powered randomized trials and investigation of repeated administration protocols with longer follow-up periods to determine efficacy and optimal clinical implementation. Full article

Background and Objectives: Ketamine and magnesium sulfate (MgSO₄) are NMDA receptor antagonists that act through distinct mechanisms. Preclinical data indicate that their analgesic interaction is sequence-dependent: ketamine administered before MgSO₄ produces synergistic antinociception, whereas the reversed sequence is antagonistic. The primary outcomes were postoperative pain intensity (Numerical Rating Scale, NRS 0–10, at rest and on movement) and cumulative intravenous morphine consumption over 48 h, evaluated in patients undergoing open radical nephrectomy to test the hypothesis of sequence-dependent analgesic interaction. Materials and Methods: In this randomized, double-blind, placebo-controlled trial, 208 patients scheduled for elective open radical nephrectomy received two sequential intravenous boluses intraoperatively: Drug A immediately after induction, Drug B 10 min later. Agents were ketamine 0.2 mg/kg, MgSO₄ 15 mg/kg, or placebo (0.9% NaCl) in all nine possible combinations. Primary outcomes were postoperative pain intensity (NRS 0–10, at rest and on movement) and cumulative intravenous morphine consumption, assessed at 14 time points over 48 h. Secondary outcomes included sedation, nausea, vomiting, and the presence of hallucinations. Results: The ketamine → MgSO₄ (K → Mg) sequence significantly reduced NRS pain scores compared to placebo at multiple time points, including 30 min, 1 h, 3 h, 6 h, and 32 h postoperatively, with differences exceeding the minimum clinically important difference of 2 NRS points at the earliest assessments. The MgSO₄ → ketamine (Mg → K) sequence did not differ from placebo at any time point. Cumulative morphine consumption was comparable across groups. No hallucinations or psychomimetic events were observed. Conclusions: Intraoperative ketamine followed by MgSO₄ (K → Mg) provides clinically meaningful postoperative analgesia after open radical nephrectomy; the reversed sequence (Mg → K) offers no benefit over placebo. These findings provide the first clinical confirmation of sequence-dependent NMDA receptor antagonism and support the K → Mg protocol as a safe, simple addition to multimodal perioperative analgesia. Trial registration: ISRCTN registry, ISRCTN83633282. Full article

Background: Magnesium sulfate (MgSO₄) has been investigated as an adjuvant in perioperative analgesia because of its antagonistic effects on the N-methyl-D-aspartate receptor (NMDA receptor) and its potential to attenuate central sensitization. However, clinical findings regarding its analgesic efficacy remain inconsistent across surgical procedures. Lumbar microdiscectomy is a common spinal procedure in which effective early postoperative pain control is important for patient comfort and early mobilization. This study aimed to evaluate the effect of intraoperative MgSO₄ administration on early postoperative analgesia and perioperative outcomes in patients undergoing lumbar microdiscectomy. Methods: This retrospective single-center cohort study included thirty-eight patients with American Society of Anesthesiologists (ASA) physical status I–II who underwent elective single-level lumbar microdiscectomy under general anesthesia. Patients were divided into two groups according to intraoperative magnesium administration: a control group receiving standard anesthesia without MgSO₄ (n = 19) and an MgSO₄ group receiving an intravenous MgSO₄ bolus of 30 mg/kg followed by a continuous infusion of 10 mg/kg/h until skin closure (n = 19). Postoperative pain intensity was assessed using the Numeric Rating Scale (NRS) at 0, 5, 10, 15, and 30 min after admission to the post-anesthesia care unit. Secondary outcomes included intraoperative remifentanil consumption, extubation time, and time to first mobilization. Complementary in silico analyses included molecular docking and protein–protein interaction (PPI) network analysis. Results: Postoperative NRS scores were numerically lower in the MgSO₄ group; however, between-group differences were not statistically significant. Mean intraoperative remifentanil consumption was numerically lower in the MgSO₄ group (236 ± 166 µg) compared with the control group (319 ± 298 µg), without statistical significance (p = 0.27). Repeated-measures analysis demonstrated the significant effect of time on postoperative NRS scores, whereas the overall group effect was not significant. Molecular analyses indicated stable morphine binding to opioid receptors and highlighted glutamatergic signaling components as central nodes within the interaction network. Conclusions: Intraoperative MgSO₄ administration was not associated with significant improvements in early postoperative pain scores or perioperative recovery parameters following lumbar microdiscectomy. Molecular analyses provide exploratory in silico insights and should be interpreted cautiously given the retrospective design and the in silico nature of these findings. Full article

Background/Objectives: Schizophrenia is a severe psychiatric disorder frequently characterised by sleep and circadian disturbances, which are closely linked to cognitive dysfunction, symptom exacerbation, and poor functional outcomes. A growing body of evidence implicates the orexin (hypocretin) system—an essential regulator of arousal, sleep–wake stability, metabolic processes, and motivated behaviour—in the pathophysiology and treatment response of psychotic disorders. We aimed to investigate the relationships between the orexinergic system and psychoses. Methods: On 3 March 2026, we searched the PubMed, Scopus, PsycInfo/Articles and Cinahl databases for studies dealing with the orexin system and psychotic disorders and treatment response. Results: We found 20 eligible studies reporting variable and inconsistent alterations in orexin signalling in patients with schizophrenia. Studies were mostly cross-sectional and heterogeneous in design. Antipsychotic medications interfere with orexin-dependent pathways, potentially contributing to both therapeutic effects and adverse outcomes such as sleep disruption and metabolic dysregulation. Conclusions: While evidence from preclinical studies could point to an influence of dopaminergic activity through orexinergic mechanisms, with possible attenuation of antipsychotic-induced motor side effects and improvement of attentional deficits associated with NMDA receptor hypofunction, the utility of dual orexin receptor antagonists (DORAs) in psychoses is unclear. Despite the high prevalence of insomnia in schizophrenia, its pharmacological management remains suboptimal, with current treatments often limited by reduced efficacy or tolerability concerns. DORAs, which are currently approved medications for the treatment of insomnia, represent a novel and mechanistically distinct therapeutic option that may improve sleep while modulating arousal- and cognition-related circuits relevant to psychosis. Full article

The mechanism of action of drugs used to treat ADHD has not been fully elucidated. The aim of the study was to assess the effect of clonidine, a drug used to treat ADHD, on interictal-like epileptiform events in prefrontal cortex pyramidal neurons. Epileptiform events (lasting less than 3 s) were recorded in a zero-magnesium and elevated-potassium proepileptic extracellular solution using the patch-clamp methodology. Clonidine 100 µM reduced the frequency of epileptiform events. Moreover, clonidine hyperpolarized the membrane potential recorded in the proepileptic extracellular solution. In the constant presence of the alpha-2 adrenergic receptor antagonist idazoxan 20 µM in all solutions, clonidine 100 µM also inhibited the frequency of interictal-like epileptiform events. This suggests that clonidine inhibited the frequency of interictal events via a direct influence on ionic channels. Furthermore, clonidine inhibited tonic NMDA receptor currents and did not influence tonic AMPA currents. The tested drug inhibited fast-inactivating voltage-gated sodium currents. Blockade of NMDA currents and voltage-gated sodium currents likely contributed to the inhibition of epileptiform events exerted by clonidine. The potential translational relevance of the study is discussed. Full article

Background: The discovery of electroencephalogram (EEG) biomarkers of direct transmitter–receptor interactions in studies of neurotransmitter mechanisms underlying brain function remains relevant. Recently, EEG “signatures” of monoaminergic systems have been demonstrated using the “time-frequency clustering” approach. In the current study, the glutamic and cholinergic systems were under similar analysis with additional emphasis on their potential interaction. Methods: In non-anesthetized freely moving rats, we studied the EEG effects of agonists for glutamate receptors, injected into the cerebral lateral ventricles, and their modification after pretreatment with corresponding antagonists. The same protocol was used for acetylcholine receptors, activating and blocking substances that penetrate the blood–brain barrier (BBB) after subcutaneous injections. A clustering of significant time-dependent changes in tiny frequency subranges of the EEG spectra was performed. Results: After injections of agonists for glutamate receptors, two clusters with enhanced and suppressed activities around 2/4 and 10 Hz, respectively, were observed in the EEG spectra. These effects were reduced by pretreatment with corresponding receptor blockers. A cholinomimetic, physostigmine, decreased EEG activity around 2 and 10 Hz and increased near 5 and 22 Hz. Scopolamine, blocking muscarinic cholinoreceptors, weakened the effects of physostigmine. Intracerebral pretreatment with NMDA and AMPA receptor blockers differently modified the effects of physostigmine. The results demonstrate the EEG biomarkers of glutamatergic and cholinergic systems, as well as the specificity of interactions between them at the intracerebral level. Conclusions: The developed EEG time-frequency clustering is a potentially useful approach for the clinical evaluation of glutamatergic/cholinergic pathology and its correction by corresponding substances penetrating the BBB. Full article

Alzheimer’s disease is a progressive neurodegenerative disorder marked by cognitive decline, and its global prevalence is expected to increase substantially in the coming decades. This review examines current therapeutic approaches and explores the potential role of medicinal plants and natural products in the treatment and prevention of Alzheimer’s disease. This review examines the pathophysiology of Alzheimer’s disease, with particular emphasis on the cholinergic, amyloid, and tau hypotheses. It evaluates currently approved therapeutic approaches, including cholinesterase inhibitors and NMDA receptor antagonists, as well as emerging immunotherapies. In addition, this review provides a comprehensive analysis of the pharmacological properties of various medicinal plants and explores innovative drug delivery systems. Research reveals that while conventional drugs like donepezil and memantine provide symptomatic relief, they do not halt disease progression. Recent immunotherapies, including lecanemab and donanemab, show potential to reduce amyloid-beta accumulation and slow cognitive decline; however, they face safety concerns, such as amyloid-related imaging abnormalities, and high costs. By comparison, several natural products—including huperzine A, curcumin, resveratrol, and epigallocatechin-3-gallate—demonstrate multi-target therapeutic potential through anti-inflammatory, antioxidant, and cholinergic-modulating mechanisms. This review offers a comprehensive contrast between natural products and traditional drugs as well as the safety and economic limitations of immunotherapies. Given the multifactorial nature of AD, therapeutic strategies that address multiple pathological pathways appear necessary. In this regard, plant-derived compounds, due to their broad pharmacological activity and generally favorable safety profiles, emerge as promising candidates for long-term management and may contribute meaningfully to the development of future therapeutic approaches for AD. Full article

This narrative literature review explores the clinical use of Ketamine as part of an untested hypothetical model framework for bridge therapy for acute suicidality. Long-term suicide rates continue to increase in the United States and in many other countries, creating a pressing public health challenge with a variety of treatment considerations. Existing standard-of-care SSRI therapeutics have a delay between administration and symptom relief at 2–6 weeks, leaving a so-called danger zone of about 1–3 months of risk for suicidal follow-through behaviors. Ketamine, a potent NMDA (N-methyl-D-aspartate) receptor antagonist, has recently seen widespread interest in both regulatory and clinical settings for increasing neuroplasticity and alleviating depressive symptoms. Ketamine’s mechanism-of-action through mTORC1 is much faster than SSRI’s downstream transcriptional regulation, leading to quicker relief of suicidal symptoms and the removal of the danger zone lag period. The current literature suggests that a controlled, supervised subanesthetic dose of Ketamine in a clinical setting has low risks of addiction or abuse, distinguishing therapeutic uses of Ketamine from recreational uses. While the biological efficacy of Ketamine is established, this conceptual review focuses on a possible initial hypothetical framework of a “Bridge Protocol.” We searched PubMed, Google Scholar, The Cochrane Library, and PsycINFO (January 2000–December 2025) to synthesize evidence regarding SSRI latency, acute Ketamine protocols, and post-discharge safety. We conclude that while promising, the proposed Ketamine Bridge Therapy requires rigorous longitudinal validation and sustained clinical studies before it can be safely used and experience widespread adoption. Full article

Ischemic stroke is a leading cause of global neurological mortality and disability, characterized by a complex pathogenesis wherein calcium overload constitutes a pivotal mechanism in neuronal and glial cell death. Following ischemia and reperfusion, excitotoxicity triggered by excessive glutamate release activates NMDA receptors and voltage-dependent calcium channels, leading to a large accumulation of intracellular Ca²⁺. This calcium dyshomeostasis subsequently initiates a cascade of detrimental events, including mitochondrial dysfunction, endoplasmic reticulum stress, reactive oxygen species generation, and the activation of calcium-dependent enzymes (such as calpain and phospholipase A₂), ultimately culminating in cellular apoptosis or necrosis. In addition, calcium signaling imbalance is closely related to various forms of programmed cell death, such as ferroptosis and necroptosis. Research on calcium overload extends beyond neurons, with investigations in microglia and astrocytes yielding significant mechanistic insights. Although targeted interventions, encompassing calcium channel blockers, NMDA receptor antagonists, mitochondrial calcium homeostasis regulators, and calmodulin/calmodulin kinase (CaM/CaMK) inhibitors, have demonstrated preclinical progress, their clinical translation remains constrained. Future investigations should prioritize elucidating the nuanced regulatory mechanisms of calcium signaling pathways, developing highly selective and low-toxicity calcium intervention drugs, and combining multi-target treatment strategies such as neuroprotection, anti-inflammation, and tissue repair to provide theoretical basis and new solutions for the precise treatment of ischemic stroke. Full article

Background and Objectives: Traumatic brain injury (TBI) triggers oxidative stress, mitochondrial dysfunction, and sterile inflammation. Amantadine (ATD), a weak NMDA receptor antagonist, has shown neuroprotective potential, but its mechanistic basis remains unclear. This study examined whether ATD treatment is associated with changes in molecular and histological markers related to the HIF-1α/BNIP3L/HMGB1-mediated hypoxia–mitophagy–inflammation response in a rat TBI model. Materials and Methods: Thirty-two Wistar rats were assigned to four groups: sham, trauma, trauma + ATD (1 day), and trauma + ATD (7 days). TBI was induced using the impact-acceleration model, and ATD (45 mg/kg, i.p.) was administered post-injury. Oxidative stress indices (TOS, TAS, OSI), histopathology, inflammatory/apoptotic markers (CRP, TNF-α, Caspase-3), and gene expression (HIF-1α, BNIP3L, HMGB1) were evaluated. Results: ATD improved oxidative balance and histopathological integrity while reducing TNF-α, CRP, and Caspase-3 immunoreactivity. qPCR analysis showed lower HIF-1α, BNIP3L, and HMGB1 expression in ATD-treated groups, which is consistent with attenuation of hypoxia-related, mitochondrial stress-associated, and damage-associated molecular pattern-associated signaling after injury. Conclusions: In this experimental model, amantadine ameliorated oxidative, inflammatory, and apoptotic markers and was associated with reduced expression of HIF-1α, BNIP3L, and HMGB1. These findings support a mechanistic correlation between ATD treatment and suppression of secondary injury signatures; however, causal pathway relationships and functional neurological outcomes were not assessed. Full article

Background: Cognitive disorders are a class of neurological diseases characterized by declines in cognitive function, imposing a heavy physical and mental burden on middle-aged and elderly individuals. Since the underlying mechanisms of cognitive disorders are not yet fully understood, and different types of cognitive disorders may involve distinct mechanisms, the development of drugs with multi-target therapeutic and preventive effects is of great significance. Currently approved drugs for Alzheimer’s disease, such as acetylcholinesterase inhibitors and NMDA receptor antagonists, show limited efficacy and poor prognosis, highlighting the urgent need for safe and effective alternative treatments. Methods: Plant-derived polysaccharides (PDPs) possess antioxidant, anti-inflammatory, neuroprotective, and immunomodulatory activities, and polysaccharides derived from traditional Chinese medicine, in particular, show great potential for treating cognitive disorders. In recent years, interventions with plant polysaccharides that modulate the gut microbiota to affect the “gut–brain axis” and improve cognitive function have become an emerging research focus. Clinical evidence has also increasingly supported the beneficial effects of polysaccharides on cognitive disorders. Therefore, this study focuses on plant polysaccharides in the intervention of cognitive disorder-related diseases, including both in vivo and in vitro experiments, and summarizes existing findings according to different mechanisms of action. Results and Conclusions: Relevant clinical reports are incorporated to provide a theoretical basis and strong support for the development of polysaccharide-based interventions and new drug development for cognitive disorders. Full article

Background: Ketamine and magnesium sulfate are commonly used perioperatively to prevent shivering, a frequent and clinically relevant complication of spinal and general anesthesia. Although their hypothermic effects are well documented, the neurotransmitter mechanisms underlying these effects remain insufficiently understood. This study examines whether serotonergic, adrenergic (α₂), and GABAergic (GABA_A) systems contribute to hypothermia induced by ketamine and a ketamine–magnesium sulfate combination. Methods: Body temperature was measured in Wistar rats after administration of ketamine (10 mg/kg) or the ketamine (5 mg/kg)–magnesium sulfate (5 mg/kg) combination. To assess neurotransmitter involvement, animals received yohimbine (α₂ antagonist), methysergide (non-selective 5-HT antagonist), or bicuculline (GABA_A antagonist) prior to ketamine or the drug combination. Data were analyzed using two-way repeated measures ANOVA followed by Tukey’s post hoc test. Results: Yohimbine at 0.5 and 1 mg/kg significantly potentiated ketamine-induced hypothermia, while only 3 mg/kg enhanced the effect of the ketamine–magnesium sulfate combination. Methysergide had a bidirectional influence: 1 mg/kg methysergide deepened ketamine-induced hypothermia, whereas 0.5 mg/kg methysergide attenuated the hypothermic effect of the ketamine–magnesium sulfate combination. Bicuculline (1–2 mg/kg) did not alter the hypothermic responses to ketamine or the combination. Conclusions: These findings indicate that ketamine- and ketamine–magnesium sulfate-induced hypothermia is primarily modulated by serotonergic and adrenergic mechanisms, whereas GABA_A receptor-dependent pathways do not appear to play a major role under the experimental conditions used. These results provide new mechanistic insights into NMDA antagonist–related thermoregulation and may help inform anesthetic strategies for shivering prevention and maintenance of perioperative thermal stability. Full article

The blood–brain barrier (BBB) is a major obstacle to the development of brain-targeted drug delivery systems, restricting greater than 98% of small molecules (<500 Da) and virtually all large-molecule drugs from entering the brain tissues from the bloodstream, resulting in suboptimal drug doses and therapeutic failure in the treatment of Alzheimer’s disease (AD). However, the advent of nanotechnology has provided significant solutions to the BBB challenges, enabling particle size reduction, enhanced drug solubility, reduced premature drug degradation, extended and sustained drug release, enhanced drug transport across the BBB, increased drug target specificity and enhanced therapeutic efficacy. In corollary, a library of brain-targeted surface-functionalized nanotherapeutics has been widely reported in the current literature. These promising in vitro, in vivo and pre-clinical results from the existing literature provide quantitative evidence for the relative clinical utility of each of the techniques, indicating remarkable capacity for brain-targeted carrier systems; many of them are still being tested in human clinical trials. However, despite the recorded research successes in drug transport across the BBB, there are currently no clinically proven medications that can slow or reverse the progression of AD because most of the novel therapeutics have not been successful during the clinical trials. Therefore, the main option for the treatment of AD is symptomatic treatment using cholinesterase inhibitors and N-methyl-D-aspartate (NMDA) receptor antagonists. Although these therapies help to alleviate symptoms of AD and improve patients’ quality of life, they neither slow the progression of disease nor cure it. Thus, an effective disease-modifying therapy for the treatment of AD is an unmet clinical need. It is apparent that a deeper understanding of the structural complexity and controlling dynamic functions of the BBB in tandem with a comprehensive elucidation of AD pathogenesis are crucial to the development of novel nanocarriers for the effective treatment of AD. Therefore, this narrative review describes the contextual analysis of several promising strategies that enhance brain-targeted drug delivery across the BBB in AD treatment and recent research efforts on two major AD biomarkers that have revolutionized AD diagnosis, amyloid-beta plaques and phosphorylated tau protein tangle, as potential targets in AD drug development. This has led to the Food and Drug Administration (FDA)’s approval of two intravenous (IV) anti-amyloid monoclonal antibodies, Lecanemab (Leqembi^®) and Donanemab (Kisunla^®), which were developed based on the Aβ cascade hypothesis for the treatment of early AD. This review also discusses the recent shift in the Aβ cascade hypothesis to Aβ oligomer (conformer), a soluble intermediate of Aβ, which is the most toxic mediator of AD and could be the most potent drug target in the future for a more accurate and effective drug development model for the treatment of AD. Furthermore, various promising nanoparticle-based drug carriers (therapeutic nanoparticles) that were developed from intensive research are discussed, including their clinical utility, challenges and prospects in the treatment of AD. Overall, it suffices to state that the advent of nanotechnology provided several innovative techniques for overcoming the BBB and improving drug delivery to the brain; however, their long-term biosafety is a relevant concern. Full article

Background/Objectives: Infantile epileptic spasms syndrome (IESS) is a severe epilepsy of infancy. Corticotropin (ACTH) and vigabatrin are the only FDA-approved therapies. The efficacy of ACTH together with the strong convulsant effects of corticotropin-releasing hormone (CRH) suggests that excess CRH, secondary to impaired ACTH feedback, may contribute to spasms. We therefore hypothesized that CRH receptor 1 (CRHR1) antagonists would suppress spasms in a route- and drug-dependent manner. Methods: Using our validated rat model of IESS, in which prenatal priming with betamethasone was followed by postnatal triggering of spasms with N-methyl-D-aspartic acid (NMDA), we tested two CRHR1 antagonists, CP376395 and SN003, delivered intracranially (via intracerebroventricular or intraparenchymal infusion) or systemically. Results: Intracerebroventricular infusion of both antagonists suppressed spasms, with CP376395 providing more consistent effects. Intraparenchymal administration into the hypothalamic arcuate nucleus also reduced spasms, whereas misses into the mammillary bodies were ineffective, highlighting site specificity. Systemic administration yielded divergent results: SN003 robustly suppressed spasms, whereas CP376395 unexpectedly exacerbated them. No sex differences were observed. Conclusions: These findings demonstrate that CRHR1 blockade modifies experimental spasms in a route- and drug-specific manner and implicates discrete hypothalamic circuits, particularly those including the arcuate nucleus, in spasm generation. The divergent systemic responses between CP376395 and SN003 likely reflect differences in CRHR1 engagement (competitive and non-competitive antagonism, respectively) as well as differences in binding properties that may include differential network interactions beyond local CRH signaling or duration of receptor occupancy. In conclusion, SN003 may be a better option than CP376395 for further development as a CRHR1-targeted therapy pending additional pharmacokinetic/pharmacodynamic studies. Further work should explore dosing paradigms of CP376395 to determine if a therapeutic range for CP376395 exists. Full article

Background/Objectives: The neurotransmitter glycine is involved in several physiological and pathological conditions in the Central Nervous System. Different biological structures, including glycine receptors and transporters, are under study as targets for potential drugs acting against serious neurological and psychiatric disorders. The regulation of glycine release from nerve terminals is only partially understood. We report here preliminary evidence of the modulation of glycine release through presynaptic metabotropic glutamate receptors 1 (mGlu1) from glycinergic nerve terminals in mouse hippocampi. Methods: Purified mouse hippocampal synaptosomes labeled with [³H]glycine were used to study glycine release under superfusion conditions. Results: The group I metabotropic glutamate receptor agonist 3,5-DHPG potentiated depolarization-evoked [³H]glycine release from hippocampal synaptosomes, an effect strongly counteracted by the selective mGlu1 antagonist LY 367385. 3,5-DHPG failed to increase [³H]glycine release in Grm1^crv4/crv4 mice, a mouse model lacking mGlu1. Although further research is needed to clarify these mechanisms, data suggest that glycine-releasing hippocampal nerve terminals are endowed with presynaptic mGlu1 receptors whose activation potentiates glycine release. Conclusions: Considering that in the hippocampus, glycine is relevant as a co-agonist of glutamate at NMDA receptors and that mGlu1 receptor ligands are under study as potential drugs, we propose that the possible effects of these agents on the release of glycine should be considered when studying these compounds. Full article