Search Results (179)

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

Orthopedic and lower limb fracture surgeries are among the most frequent emergency procedures and are commonly performed under general anesthesia (GA). Background and clinical significance: Epidemiologically, postoperative coma after GA is rare (0.005–0.08%), but delayed awakening (2–4%) and postoperative delirium or postoperative cognitive dysfunction (POCD) (15–40%) remain significant. These neurological complications increase markedly in vulnerable brain patients with psychiatric, cerebrovascular, or neurodegenerative disorders. Methods: This mechanistic narrative review synthesizes evidence from clinical and experimental studies (1990–2025) comparing the effects of general versus Regional (RA)/local (LA) or spinal anesthesia in vulnerable neuropsychiatric populations “with pre-existing brain illness” undergoing orthopedic surgery. Domains analyzed include neuropsychiatric medications effects and interactions with the GA process and with general anesthetic agents, alongside alterations in neurotransmitter modulation, cerebrovascular autoregulation, mitochondrial dysfunction, oxidative stress, redox imbalance, and neuroinflammatory activation. The review summarizes evidence on how the choice of anesthesia type influences postoperative brain outcomes in patients with known neurological conditions. Results: From previous studies, patients with psychiatric and/or chronic brain illness have a 3–5-fold increased risk of delayed emergence and up to 60% incidence of postoperative delirium. Pathophysiological mechanisms involve GABAergic overinhibition, impaired perfusion, mitochondrial energy failure, and inflammatory amplification. Regional/local and spinal anesthesia may offer physiological advantages, preserve cerebral perfusion, and lower neurological complication rates. Conclusions: General anesthesia may exacerbate pre-existing brain vulnerability, converting reversible neural suppression into irreversible dysfunction. Therefore, whenever possible, regional/local or spinal anesthesia with or without sedation should be prioritized in those neurologically vulnerable patients to reduce the length of hospital stay (LOS) and to lower postoperative neurological complications and risks in psychiatric and neurologically unstable patients. Full article

The way in which Aquaporin-4 (AQP4) is localized on the astrocytes’ surface—i.e., with AQP4 channels predominantly located on the endfeet of astrocytes near the blood vessels—represents an important structural element for maintaining brain fluid homeostasis. In addition to this structural function, AQP4 polarity also facilitates glymphatic transport, the maintenance of the blood–brain barrier (BBB) functions, ion buffering, and neurotransmitter removal, and helps regulate neurovascular communications. The growing body of literature suggests that the loss of AQP4 polarity—a loss in the organization of AQP4 channels to the perivascular membrane—is associated with increased vascular, inflammatory, and metabolic disturbances in the context of many neurological diseases. As a result, this review attempts to synthesize both experimental and clinical studies to highlight that AQP4 depolarization often occurs in conjunction with early signs of neurodegeneration and neuroinflammation; however, we are aware that the loss of AQP4 polarity is only one factor in a complex pathophysiological environment. This review examines the molecular structure responsible for maintaining the polarity of AQP4—such as dystrophin–syntrophin complexes, orthogonal particle arrays, lipid microdomains, trafficking pathways, and transcriptional regulators—and describes how the vulnerability of these systems to various types of vascular stress, inflammatory signals, energy deficits, and mechanical injury can lead to a loss of AQP4 polarity. Furthermore, we will explore how a loss of AQP4 polarity can lead to the disruption of perivascular fluid movement, changes in blood–brain barrier morphology, enhanced neuroimmune activity, changes in ionic and metabolic balance, and disruptions in the global neural network synchronization. Importantly, we recognize that each of these disruptions will likely occur in concert with other disease-specific mechanisms. Alterations in AQP4 polarity have been observed in a variety of neurological disorders including Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, traumatic brain injury, and glioma; however, we also observe that the same alterations in fluid regulation occur across all of these different diseases, but that no single upstream event accounts for the alteration in polarity. Ultimately, we will outline emerging therapeutic avenues to restore perivascular fluid transport, and will include molecular-based therapeutic agents designed to modify the anchoring of AQP4, methods designed to modulate the state of astrocytes, biomaterials-based drug delivery systems, and therapeutic methods that leverage dynamic modulation of the neurovascular interface. Future advances in multi-omic profiling, spatial proteomics, glymphatic imaging, and artificial intelligence will allow for earlier identification of AQP4 polarity disturbances and potentially allow for the development of more personalized treatment plans. Ultimately, by linking these concepts together, this review aims to frame AQP4 polarity as a modifiable aspect of the “fluidic connectome”, and highlight its importance in maintaining overall brain health across disease states. Full article

While free amino acids (FAAs) are often regarded as simple building blocks for proteins, various studies show they have more complex roles in the body. This review expands on the FAA’s functions, emphasizing their influence on diverse biological processes. It covers their significance in metabolism, energy production, and the synthesis of neurotransmitters, hormones, and antioxidants. FAAs also serve as signaling molecules that regulate critical pathways related to cell growth, autophagy, and metabolic control. The review highlights their impact on the immune system and their essential roles in gut health, nutrient sensing, and metabolic communication. Drawing on recent findings, we emphasize the importance of measuring FAA levels in biological samples and suggest that their supplementation could be beneficial in clinical nutrition, treating metabolic or immune disorders, and preventing sarcopenia. Overall, FAAs are presented as key signaling agents and biomarkers, with potential for targeting their levels to improve health and treat diseases. Full article

The digital transformation in the treatment of mental health and emotional disharmony requires artificial intelligence architectures that overcome the limitations of purely neural approaches, such as temporal inconsistency, opacity, and lack of theoretical foundations. Assuming the existence and use of generalist LLMs currently used in clinical settings and considering the appropriate limitations indicated by experts, this article aims to offer clinicians an alternative Neuro-symbolic-Psychological multi-agent architecture (NSPA-AI), which integrates archetypal symbolic reasoning with neurobiological modelling, based on our established framework of artificial neurotransmitters for the modelling and analysis of affective-emotional stimuli to enable interpretable AI-assisted psychological intervention. The system implements a hub-and-spoke topology that coordinates five specialized agents (symbolic, psychological, neurofunctional, decision fusion, learning) that process heterogeneous information via SPADE protocols. Seven archetypal constructs from Jungian psychology and narrative identity theory provide stable symbolic frameworks for longitudinal therapeutic consistency. An empirical study of 156 university students demonstrated significant improvements in depression (Cohen’s d = 1.03), stress (d = 0.89), and narrative identity integration (d = 0.75), which were maintained at a 12-week follow-up and superior to GPT-4 controls (d = 0.34). Neurofunctional correlations—downregulation of cortisol (r = 0.71 with stress reduction), increase in serotonin (r = −0.68 with depression improvement)—validated the neurobiological basis of the entropy-energy framework. Qualitative analysis revealed the following four mechanisms of improvement: symbolic emotional support (93%), increased self-awareness through neurotransmitter visualization (84%), non-judgmental AI interaction (98%), and archetypal narrative organization (87%). The results establish that neuro-symbolic architectures are viable alternatives to large language models for digital mental health, providing the interpretability and clinical validity essential for adoption in the healthcare sector. Full article

Background/Objectives: One of the neurotoxic components from the sea trumpet polyps, Protopalythoa variabilis (Cnidaria, Anthozoa), is a 26-residue, V-shape helical peptide (PpVα). Its synthetic versions, i.e., the linear, the single-disulfide-bonded analog, and the chimeric peptide with a 6-residue stretch of the N-terminal native homologous peptide covalently linked to the linear sequence, were investigated for their activity on ion channels responsible for cellular excitability and synaptic transmission. Methods: Molecular docking analyses and dynamic simulations focused on the ability of PpVα peptides to bind ion channels selectively through interaction with critical residues at their binding sites. Results: Electrophysiological studies using the patch clamp technique with sympathetic bovine chromaffin cells from the adrenal medulla confirmed that PpVα analogs can block both sodium and calcium currents, which are responsible for initiating and propagating action potentials, respectively, and for neurotransmitter release. Additionally, the peptides displayed neuroprotective effects, attenuating cellular damage induced by veratridine, which interferes with sodium channel activity, and by oligomycin and rotenone (O/R), which affect mitochondrial function. Conclusions: The block of calcium and sodium channels and the neuroprotective effects against oxidative stress make the PpVα peptide scaffold an attractive template for developing agents that has significant clinical potential in several areas, such as the treatment of neurological diseases (epilepsy, multiple sclerosis, and neurodegenerative diseases), neuroprotection in acute events (stroke and traumatic brain or spinal cord injuries), the management of neuropathic pain, the prevention of ischemic damage, and psychiatric disorders (anxiety and bipolar disorder). Full article

Diabetic neuropathy is characterized by nerve damage and chronic neuropathic pain and lacks effective treatment. Botulinum neurotoxin type A (BoNT/A), a neurotoxin with established therapeutic use in neurological disorders, has emerged as a potential analgesic agent. This study investigated the effects of a recombinant form of BoNT/A1 (rBoNT/A1) on neuropathic pain induced by spared nerve injury (SNI) in a diabetic mouse model. Thirty-two adult male C57BL/6JRj diabetic mice were subjected to SNI or sham surgery. Fourteen days post surgery, mice received an intraplantar dose of rBoNT/A1 or vehicle. Mechanical allodynia was assessed using von Frey filaments, and spinal cord and sciatic nerve tissues were analyzed via immunohistochemistry and transmission electron microscopy to evaluate glial activation, neurotransmitter receptor expression, and axonal morphology. The results demonstrated that rBoNT/A1 significantly alleviated mechanical allodynia and caused a marked reduction in Iba1-positive microglial activation in the spinal cord, whereas no significant changes were observed in astrocyte (GFAP) density or GABAAR subunit expression. Additionally, rBoNT/A1 treatment did not significantly alter axon diameter, myelin thickness, or C-fiber morphology. In conclusion, intraplantar administration of rBoNT/A1 reduced SNI-induced mechanical allodynia in diabetic mice, potentially by attenuating spinal microglial activation, supporting the therapeutic promise of rBoNT/A1 in managing diabetic neuropathic pain. Full article

N-chlorotaurine (Tau-Cl) is a mild oxidizing haloamine formed from the reaction of hypochlorous acid (HOCl) with taurine (2-amino-ethanesulfonic acid). It is widely used as a topical antiseptic. In this study, we investigated haloamines derived from the neurotransmitter γ-aminobutyric acid, specifically GABA chloramine and bromamine (GABA-Cl, GABA-Br), as well as their halogenated γ-aminobutyric acid ethyl esters (GABAet-Cl, GABAet-Br). Due to their higher hydrophobicity, the esterified haloamines were more potent oxidants in the presence of lyophilic surfactant micelles, demonstrating their greater ability to access hydrophobic environments. By using fluorescent azapentalenes as molecular targets incorporated into sodium dodecyl sulfate (SDS) micelles, the second-order oxidation rate constants (k₂) resulted in 1.15 × 10² and 1.10 × 10⁴ M⁻¹min⁻¹ for GABA-Cl and GABAet-Cl, respectively. As expected, due to the presence of a bromine atom, GABAet-Br was even more reactive (4.50 × 10⁶ M⁻¹min⁻¹). The ability of GABAet-Br to access hydrophobic sites was demonstrated by comparing the reaction rate using micelles generated by different surfactants such as SDS (4.5 × 10⁶ M⁻¹min⁻¹), cetyltrimethylammonium chloride (CTAC, 2.5 × 10⁴ M⁻¹min⁻¹), and triton X-100 (TX-100, 3.9 × 10³ M⁻¹min⁻¹). GABAet-Cl and GABAet-Br exhibited higher bactericidal activity against Staphylococcus aureus and Escherichia coli, probably due to their increased lipophilicity and improved penetration into microorganisms compared to GABA-Cl and GABA-Br. The enhancement of the oxidation capacity by GABAet-Cl and GABAet-Br represents a new direction in the exploration and application of haloamines as antiseptic agents. Full article

Insomnia is a common and complex disorder, rooted in the dysregulation of circadian rhythms, impaired neurotransmitter function, and disturbances in sleep–wake homeostasis. While conventional hypnotics such as benzodiazepines and Z-drugs are effective in the short term, their use is limited by a high potential for dependence, cognitive side effects, and withdrawal symptoms. In contrast, melatonergic receptor agonists—melatonin, ramelteon, tasimelteon, and agomelatine—represent a pharmacologically targeted alternative that modulates MT1 and MT2 receptors, which are pivotal to the regulation of circadian timing and sleep initiation. Clinical evidence supports the efficacy of these agents in reducing sleep onset latency, extending total sleep duration, and re-aligning disrupted circadian rhythms, particularly among older individuals and patients with non-24 h sleep–wake disorders. Notably, agomelatine offers additional antidepressant properties through selective antagonism of the 5-HT_2C receptor in micromolar concentrations. In contrast, its agonistic activity at melatonergic receptors is observed in the low sub-nanomolar range, which illustrates the complexity of this drug’s interactions with the human body. All compounds reviewed demonstrate a generally favorable safety and tolerability profile. Accumulating evidence highlights that selected medicinal plants, such as chamomilla, lemon balm, black cumin, valeriana, passionflower and lavender, may exert relevant hypnotic or anxiolytic effects, thus complementing melatonergic strategies in the management of insomnia. This structured narrative review presents a comprehensive analysis of the molecular pharmacology, receptor affinity, signaling pathways, and clinical outcomes associated with melatonergic agents. It also examines their functional interplay with serotonergic, GABAergic, dopaminergic, and orexinergic systems involved in arousal and sleep regulation. Through comparative synthesis of pharmacokinetics and neurochemical mechanisms, this work aims to inform the development of evidence-based strategies for the treatment of insomnia and circadian rhythm sleep–wake disorders. Full article

Background/Objectives: Neurotransmitters such as dopamine and serotonin are critical regulators of mood, cognition, and neuronal homeostasis. This study aimed to evaluate the neuropharmacological potential of Hawaiian plants by investigating their ability to modulate the expression of tyrosine hydroxylase (TH) and tryptophan hydroxylase (TPH), key enzymes in neurotransmitter biosynthesis. Methods: A total of 108 aqueous and methanolic extracts of Hawaiian plants were screened for cytotoxicity against PC-12 and Neuro-2A cells using the MTT assay. Fifty-six non-toxic extracts were selected and further analyzed for TH and TPH expression via quantitative real-time PCR (qPCR). Results: Several extracts significantly upregulated TH and TPH expression without inducing cytotoxicity. Extracts derived from Morinda citrifolia, Pipturus albidus, and Hedychium coronarium showed the most notable activity, suggesting their potential to enhance dopaminergic and serotonergic pathways. Conclusions: The findings highlight the promise of native Hawaiian flora as sources of neuroactive compounds that may support neuroprotection and regeneration. These results provide a foundation for in vivo studies and further exploration of novel neurotherapeutic agents. Full article

Gilles de la Tourette syndrome (GTS) is a neurodevelopmental disorder characterized by motor and phonic tics, often including attention deficit, hyperactivity, and obsessive–compulsive behaviours. The pathophysiology involves the dysfunction of cortico-striato-thalamo-cortical circuits, primarily implicating dopaminergic hyperactivity, but also involving multiple different neurotransmitter systems. Treatment of GTS is complex, highly individualized, and influenced by considerable variability in symptom presentation. Behavioural approaches, such as Habit Reversal Therapy (HRT), play a key role, especially in milder cases. Pharmacological therapy is largely empirical and varies across countries, influenced by drug availability and the perceived risks of certain classes of drugs, particularly dopamine receptor blocking agents. Drug options for managing tics include dopamine receptor antagonists, monoamine depleting agents, and alpha-2 agonists, all of which require close monitoring for metabolic, cardiovascular, and neurological side effects. Botulinum toxin injections represent an effective solution for focal tics that are resistant to systemic treatments. Cannabinoids and antiepileptics have limited efficacy, yet they may still offer relevant therapeutic potential in selected cases. Serotonergic drugs are useful for treating obsessive–compulsive symptoms. For patients with refractory tics, deep brain stimulation (DBS) represents an intervention of last-resort; however, DBS remains off-label and consensus on optimal targets is lacking. This narrative review draws on both the relevant literature and extensive personal clinical experience to explore the complexities of managing GTS, with a focus on evidence-based treatments for tics and associated neuropsychiatric symptoms. A therapeutic algorithm is proposed, emphasizing a “start low, go slow” approach, combining pharmacological interventions with cognitive behavioural and surgical therapies, when needed. We underscore the importance of tailoring treatments to individual patient profiles and symptom variability over time, highlighting the need for further research in GTS management. Full article

N-acetylcysteine (NAC) has garnered increasing interest for its neurotherapeutic capabilities beyond its recognized functions as a mucolytic agent and an antidote for acetaminophen toxicity. This review consolidates findings from both preclinical and clinical studies to investigate NAC’s diverse modulatory effects on the central nervous system (CNS). NAC primarily functions as an antioxidant by replenishing glutathione and mitigating oxidative stress; however, it produces glutathione-independent effects through the modulation of mitochondrial redox systems, ferroptosis, and the Nrf2-ARE signaling pathway. It plays a significant role in neuroinflammatory processes by inhibiting the production of cytokines, the expression of iNOS, and the activation of microglia. Furthermore, NAC affects various neurotransmitter systems—including glutamatergic, dopaminergic, GABAergic, serotonergic, cholinergic, and adrenergic pathways—by modulating synaptic transmission, receptor activity, and transporter functionality. It promotes neuroprotection through the enhancement of neurotrophic factors, the preservation of mitochondrial integrity, and the upregulation of survival signaling pathways. Recent evidence also emphasizes NAC’s role in gene expression and the regulation of cortisol levels. The extensive range of NAC’s neurobiological effects highlights its therapeutic potential in treating neurodegenerative and neuropsychiatric disorders. Nevertheless, the variability in clinical outcomes indicates a pressing need for more focused, mechanism-based research. Full article

Background: Glaucoma is a progressive optic neuropathy marked by retinal ganglion cells (RGCs), apoptosis, vascular insufficiency, oxidative stress, mitochondrial dysfunction, excitotoxicity, and neuroinflammation. While intraocular pressure (IOP) reduction remains the primary intervention, many patients continue to lose vision despite adequate pressure control. Emerging neuroprotective agents—citicoline, coenzyme Q10 (CoQ10), pyruvate, nicotinamide, pyrroloquinoline quinone (PQQ), homotaurine, berberine, and gamma-aminobutyric acid (GABA)—target complementary pathogenic pathways in experimental and clinical settings. Methods: This literature review synthesizes current evidence on glaucoma neuroprotection, specifically drawing on the most relevant and recent studies identified via PubMed. Results: Citicoline enhances phospholipid synthesis, stabilizes mitochondrial membranes, modulates neurotransmitters, and improves electrophysiological and visual field outcomes. CoQ10 preserves mitochondrial bioenergetics, scavenges reactive oxygen species, and mitigates glutamate-induced excitotoxicity. Pyruvate supports energy metabolism, scavenges reactive oxygen species, and restores metabolic transporter expression. Nicotinamide and its precursor nicotinamide riboside boost NAD⁺ levels, protect against early mitochondrial dysfunction, and enhance photopic negative response amplitudes. PQQ reduces systemic inflammation and enhances mitochondrial metabolites, while homotaurine modulates GABAergic signaling and inhibits β-amyloid aggregation. Berberine attenuates excitotoxicity, inflammation, and apoptosis via the P2X7 and GABA-PKC-α pathways. Preclinical models demonstrate synergy when agents are combined to address multiple targets. Clinical trials of fixed-dose combinations—such as citicoline + CoQ10 ± vitamin B3, citicoline + homotaurine ± vitamin E or PQQ, and nicotinamide + pyruvate—show additive improvements in RGCs’ electrophysiology, visual function, contrast sensitivity, and quality of life without altering IOP. Conclusions: A multi-targeted approach is suitable for glaucoma’s complex neurobiology and may slow progression more effectively than monotherapies. Ongoing randomized controlled trials are essential to establish optimal compound ratios, dosages, long-term safety, and structural outcomes. However, current evidence remains limited by small sample sizes, heterogeneous study designs, and a lack of long-term real-world data. Integrating combination neuroprotection into standard care holds promise for preserving vision and reducing the global burden of irreversible glaucoma-related blindness. Full article

Sudden Unexpected Death in Epilepsy (SUDEP) is a leading cause of mortality among individuals with epilepsy, particularly those with drug-resistant forms. This review explores the complex multisystem mechanisms underpinning SUDEP, integrating recent findings on brain, cardiac, and pulmonary dysfunctions. Background/Objectives: The main objective of this review is to elucidate how seizures disrupt critical physiological systems, especially the brainstem, heart, and lungs, contributing to SUDEP, with emphasis on respiratory control failure and autonomic instability. Methods: The literature from experimental models, clinical observations, neuroimaging studies, and genetic analyses was systematically examined. Results: SUDEP is frequently preceded by generalized tonic–clonic seizures, which trigger central and obstructive apnea, hypoventilation, and cardiac arrhythmias. Brainstem dysfunction, particularly in areas such as the pre-Bötzinger complex and nucleus tractus solitarius, plays a central role. Genetic mutations affecting ion channels (e.g., SCN1A, KCNQ1) and neurotransmitter imbalances (notably serotonin and GABA) exacerbate autonomic dysregulation. Risk is compounded by a prone sleeping position, reduced arousal capacity, and impaired ventilatory responses. Conclusions: SUDEP arises from a cascade of interrelated failures in respiratory and cardiac regulation initiated by seizure activity. The recognition of modifiable risk factors, implementation of monitoring technologies, and targeted therapies such as serotonergic agents may reduce mortality. Multidisciplinary approaches integrating neurology, cardiology, and respiratory medicine are essential for effective prevention strategies. Full article

Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by the selective loss of dopaminergic neurons in the substantia nigra, resulting in motor symptoms such as bradykinesia, tremor, rigidity, and postural instability, as well as a wide variety of non-motor manifestations. Branched-chain amino acids (BCAAs)—leucine, isoleucine, and valine—are essential nutrients involved in neurotransmitter synthesis, energy metabolism, and cellular signaling. Emerging evidence suggests that BCAA metabolism is intricately linked to the pathophysiology of PD. Dysregulation of BCAA levels has been associated with energy metabolism, mitochondrial dysfunction, oxidative stress, neuroinflammation, and altered neurotransmission. Furthermore, the branched-chain ketoacid dehydrogenase kinase (BCKDK), a key regulator of BCAA catabolism, has been implicated in PD through its role in modulating neuronal energetics and redox homeostasis. In this review, we synthesize current molecular, genetic, microbiome, and clinical evidence on BCAA dysregulation in PD to provide an integrative perspective on the BCAA–PD axis and highlight directions for future translational research. We explored the dualistic role of BCAAs as both potential neuroprotective agents and metabolic stressors, and critically examined the therapeutic prospects and limitations of BCAA supplementation and BCKDK targeting. Full article