Search Results (953)

Tardive dyskinesia (TD) is a persistent hyperkinetic movement disorder associated with prolonged dopamine D2 receptor blockade, particularly during chronic haloperidol (HP) exposure. Emerging evidence suggests that TD-like pathology is sustained by an interconnected redox–mitochondrial–inflammatory network within striatal circuits; however, the regulatory architecture of this network remains incompletely defined. Hyperoside (HS), a flavonol glycoside with cytoprotective properties, has been implicated in cellular stress-response modulation, yet its role in antipsychotic-induced motor dysfunction remains unclear. In this study, a six-group mechanistic design was employed in which rats received HP (1 mg/kg, i.p., 21 days) to induce TD-like orofacial dyskinesia (OD), quantified by vacuous chewing movements (VCMs) and tongue protrusions (TPs). HS (30 mg/kg, i.p.) was administered alone or in combination with HP, with or without pharmacological inhibition of nuclear factor erythroid 2–related factor 2 (Nrf2) using ML385. HP exposure induced progressive dyskinetic behavior accompanied by oxidative and nitrosative stress, mitochondrial dysfunction, increased pro-inflammatory cytokines, and elevated caspase-3 activity in the striatum. HS significantly attenuated behavioral abnormalities while restoring redox balance, preserving mitochondrial enzyme activities, and reducing inflammatory and apoptotic signaling. Notably, Nrf2 inhibition intensified molecular pathology without proportionally worsening behavioral outcomes, indicating a dissociation between biochemical vulnerability and overt motor expression. Furthermore, ML385 markedly attenuated HS-mediated protection across multiple endpoints. Collectively, these findings support a potential protective role for Nrf2-related regulatory mechanisms in limiting network destabilization in TD-like pathology, while highlighting the importance of integrated stress-response pathways in modulating disease progression. Full article

Memory is generally thought to be stored within centralized neural circuits. However, whether learned behaviors can persist in the absence of a brain remains unresolved. Planaria (Girardia spp.) possess a primitive cephalic ganglion and a remarkable capacity for regeneration, providing a unique system to examine non-cephalic memory retention. The primary aim of this study was to determine whether sucrose-induced conditioned place preference (CPP) is retained in posterior, brainless planarian fragments. Planaria were trained using a Pavlovian conditioning paradigm in which an initially unpreferred surface was paired with a 10% sucrose solution, resulting in a robust shift in surface preference. Following amputation, anterior fragments containing the cephalic ganglion as well as posterior fragments lacking the brain preserved the conditioned preference, demonstrating that reward-associated memory is stored even outside the cephalic nervous system. As a secondary objective, we examined the role of dopaminergic reinforcement using a D1 dopamine receptor antagonist during training. While antagonist-treated planaria failed to develop a CPP, posterior fragments from these amputated planaria likewise showed no conditioned preference, indicating that dopamine-dependent signaling is essential for sucrose-associated memory formation across the body. These results provide support for the hypothesis that reward-associated memory in planaria is distributed beyond the brain and can be modulated by dopaminergic pathways, highlighting the utility of this model for exploring fundamental mechanisms of reward, memory, and potential pharmacological interventions. Full article

Background: Chronic stress is a major contributing factor to mood disorders, including depression and anxiety; however, the molecular mechanisms underlying individual differences in susceptibility to such disorders remain poorly understood. DNA methyltransferase 3a (Dnmt3a), a key epigenetic regulator, has been increasingly implicated in stress-related neurobiological adaptations. In this study, we employed a well-established mouse model of chronic social defeat stress (CSDS) to investigate the functional role of Dnmt3a in modulating individual susceptibility to social stress. Methods: Male C57BL/6J mice were exposed to chronic/submaximal social defeat stress (CSDS/SSDS). AAV vectors were used to achieve Dnmt3a overexpression or global and oligodendrocyte-specific knockdown in the nucleus accumbens (NAc). Behavioral tests, including social interaction, open field, and elevated zero maze, were conducted alongside Western blotting and immunofluorescence assays. Results: CSDS selectively increased Dnmt3a expression in NAc oligodendrocytes of stress-susceptible mice. Overexpression of Dnmt3a in the NAc enhanced susceptibility to stress, whereas its knockdown conferred resilience, without affecting baseline behaviors. Dnmt3a negatively regulated myelin basic protein (MBP) and dopamine D1 receptor expression. Stress-susceptible mice exhibited shortened myelinated segments and reduced D1 receptor levels, while D2 receptor expression remained unchanged. Conclusions: Dnmt3a in NAc oligodendrocytes modulates susceptibility to social stress through a Dnmt3a-MBP/D1 receptor-NAc pathway, highlighting a critical glia-neuron interaction. This mechanism extends our understanding of the neurobiological basis of stress-related disorders and positions Dnmt3a as a promising therapeutic target for developing precision interventions or biomarkers. Full article

Introduction: Pathogenic mutations in leucine-rich repeat protein kinase-2 (LRRK2), particularly G2019S, constitute the most common cause of autosomal dominant PD. Methods: Mouse models encoding human mutant alpha-synuclein (SNCA A53T) and LRRK2 G2019S were treated with a brain-penetrant kinase inhibitor (BK40196). Behavior, nigrostriatal and mesolimbic dopamine (DA) pathways were examined. Results: Mice harboring LRRK2 G2019S do not show age-dependent motor symptoms, but mice encoding SNCA A53T display motor deficits, while both strains exhibit anxiety-like behavior and BK40196 improves motor and behavioral defects. BK40196, a multi-kinase inhibitor of Abelson (Abl), Discoidin domain receptor (DDR)-1, c-KIT and FYN, alters microglial morphology and alpha-synuclein levels in SNCA A53T mice and improves DA neurotransmission, primarily via the nigrostriatal system. BK40196 inhibits brain LRRK2 G2019S (IC₅₀ of 89nM) and does not affect phosphorylated or total peripheral LRRK2 levels (lungs, kidneys, liver, etc.). LRRK2 G2019S mice treated with BK40196 exhibit distinct increases in DA in mesolimbic neurons such as the nucleus accumbens (NAcc), suggesting differential mechanisms of DA neurotransmission in mutant alpha-synuclein and LRRK2 models of PD. Conclusions: LRRK2 G2019S may primarily involve mesolimbic pathways leading to nonmotor symptoms independent of the motor and behavioral manifestations associated with alpha-synuclein via the nigrostriatal system. BK40196 may provide a comprehensive and synergistic therapeutic approach that addresses multiple mechanisms to reduce the pathologies related to LRRK2 G2019S and/or SNCA in PD. The multiple pathologies of PD necessitate a holistic approach that simultaneously targets inflammation and autophagy and LRRK2 inhibition. Full article

Glucagon-like peptide-1 (GLP-1) and dual GIP/GLP-1 receptor agonists, originally introduced for the management of type 2 diabetes mellitus and obesity, are increasingly recognized for their broader actions within the central nervous system, with emerging implications in neuropsychiatry and neurodegeneration. This review integrates current preclinical and clinical evidence, emphasizing their pharmacodynamic profile, central receptor distribution, and the molecular pathways linking metabolic signaling to neural function. Evidence suggests that GLP-1 receptor activation across key brain regions involved in energy balance and reward modulates multiple neurotransmitter systems, including dopamine and serotonin, as well as glutamatergic and GABAergic transmission, thereby influencing behavior, affective processes, and cognitive function. In parallel, these agents exhibit neuroprotective properties through improved neuronal insulin sensitivity, attenuation of neuroinflammatory pathways, and support of neuroplasticity, alongside effects on limiting pathological protein aggregation. Dual GIP/GLP-1 agonism may further potentiate these central actions through complementary metabolic and synaptic mechanisms. Although pharmacovigilance data have identified isolated neuropsychiatric adverse events, current clinical evidence does not support a consistent causal association. Collectively, incretin-based therapies represent a promising translational approach at the interface of metabolic and neuropsychiatric disorders, warranting further investigation into their long-term central safety, therapeutic efficacy, and clinical relevance. Full article

Natural products represent an important reservoir for GPCR ligand discovery. In this study, we established an integrated workflow combining virtual screening, biophysical validation, functional signaling assays, and transcriptomic profiling to identify reticuline, a dopamine-derived intermediate from the genus of Stephania, as a potential agonist of dopamine D5 receptor (D5R). Molecular docking revealed that most dopamine-derived compounds along the BIA synthetic pathway exhibit predicted binding affinities for the D5R that are lower than that of dopamine. As expected, the reticuline–D5R complex has a favorable predicted binding affinity of −7.9 kcal/mol. As for binding validation, direct interaction between reticuline and D5R was experimentally confirmed using cell membrane chromatography (CMC) and bio-layer interferometry (BLI), yielding a dissociation constant of 1.07 μM. cAMP assay demonstrated that reticuline activates D5R-mediated Gs-cAMP increasement in a concentration-responsive manner, which exhibits agonist-like activity with an EC₅₀ value of 0.07 μM. The transcriptomic profiling further revealed that reticuline treatment induces transcriptional reprogramming in D5R-overexpressing cells, with enrichment of pathways related to ribosome biogenesis, mitochondrial oxidative phosphorylation, and neurodegenerative diseases. In summary, this study demonstrates that reticuline acts as a potential D5R agonist and highlights a systematic natural product-GPCR discovery strategy integrating computational prediction, experimental validation, and transcriptome-level mechanistic exploration. Full article

Substance use disorder (SUD) is a chronic neuropsychiatric condition characterized by persistent drug seeking and impaired behavioral control. Dopaminergic signaling has long been recognized as a central regulator of reinforcement learning, motivation, and habit formation. Addictive substances profoundly alter dopamine transmission through multiple mechanisms. These drug-induced changes contribute to the initiation, escalation, and persistence of addictive behaviors. In addition to dopamine, the cholinergic system has emerged as an important modulator of striatal circuit function. Acetylcholine and its receptors interact extensively with dopaminergic pathways, shaping striatal signaling dynamics and influencing learning and action selection, with particularly strong relevance for nicotine dependence. In this review, we discuss how striatal dopamine and acetylcholine contribute to learning, habit formation, and addiction-related behaviors, as well as how these systems interact at the circuit level. By integrating these findings, we propose a framework for understanding how dopamine–acetylcholine interactions may influence behavioral regulation relevant to substance use disorders. Full article

Hypertension continues to be a major global public health challenge. Dopamine generated in the kidney is a vital coordinator of sodium homeostasis and blood pressure control. Dopamine exerts its effects by activating its receptors, which are divided into the D₁-like receptor family (D₁R and D₅R) and the D₂-like receptor family (D₂R, D₃R, and D₄R). All five dopamine receptor subtypes are differentially expressed along the nephron. Dopamine receptors inhibit the activities and/or expression of renal tubular sodium transporters/exchangers/channels, decrease renal oxidative stress, and interact with other receptors, including angiotensin II receptors. Many studies have demonstrated that renal dopamine receptors play an important role in the regulation of blood pressure. The germline deletion or renal-selective silencing of any of the five dopamine receptor subtypes may impair sodium excretion and increase blood pressure. In addition, renal dopamine receptor expression and/or function are regulated by some factors such as G protein-coupled receptor kinases, oxidative stress, and sorting nexins. In this article, we summarize the role of each dopamine receptor subtype in the pathogenesis of hypertension and discuss the potential regulatory mechanisms of their expression and function. These may lead to the development of novel therapeutic approaches to the prevention and treatment of hypertension. Full article

Background: Biological sex contributes to variability in drug metabolism, receptor sensitivity, and susceptibility to adverse drug reactions (ADRs). Despite this, dosing recommendations for selective serotonin reuptake inhibitors (SSRIs) and second-generation antipsychotics (SGAs) are still largely sex-neutral. This systematic review examines sex-related differences in pharmacokinetics (PK), pharmacodynamics (PD), and safety outcomes, with the aim of clarifying their potential implications for personalized psychopharmacology. Methods: A systematic search of PubMed was conducted for studies published between January 2010 and March 2026. The strategy combined MeSH terms and free-text keywords related to SSRIs, SGAs, sex differences, pharmacokinetics, pharmacodynamics, and ADRs. Two independent reviewers performed study selection and data extraction. Studies reporting sex-stratified PK, PD, or safety outcomes in humans were included. Owing to methodological heterogeneity, results were synthesized narratively. Results: Twenty-seven studies met the inclusion criteria. Overall, the evidence indicates clinically meaningful sex-related differences in psychotropic drug exposure and response. Women more frequently exhibited higher dose-adjusted serum concentrations, particularly for risperidone and some SSRIs, with age-related increases more evident in females. Pharmacodynamic findings suggest that women may reach comparable dopamine D2 receptor occupancy at lower olanzapine doses. Pharmacovigilance analyses revealed sex-specific adverse event patterns, including greater reporting of endocrine-related effects and QT prolongation in women. Conclusions: Sex influences psychotropic drug exposure, pharmacodynamic sensitivity, and safety profiles in ways that may be clinically relevant. Integrating sex-aware considerations into dosing strategies could improve therapeutic precision and reduce adverse outcomes, reinforcing the importance of sex as a key variable in personalized psychiatric care. Full article

Introduction: Ethanol consumption is a major global health concern associated with many disorders. Melatonin, a circadian neurohormone, also modulates dopamine signaling and drug-seeking behaviors central to addiction. Objective: To investigate the role of melatonergic receptors in reducing ethanol consumption and explore melatonin’s therapeutic potential to overcome ethanol dependence in rats. Method: Male Wistar rats were acclimatized for 5 days, then divided into two groups: ethanol-naive (n = 6) and ethanol-exposed (n = 36). The ethanol group was given 10% ethanol (7 days), followed by limited access (27 days). On day 40, the ethanol group was divided into 6 sub-groups, receiving various treatments, including melatonin and receptor blockers (10 days). Ethanol and water consumption were measured daily. On day 49, the rats were sacrificed, and dopamine levels in the nucleus accumbens were quantified using an ELISA. Results: Both melatonin doses and naltrexone significantly reduced ethanol consumption (p < 0.05) compared to their pretreatment levels. Ethanol reduction was greater in the melatonin-treated groups than the control group (p = 0.004, p = 0.007). However, the melatonin’s efficacy was blocked when coadministered with receptor antagonists, showing no significant ethanol reduction vs. control (p = 0.075 and p = 0.08). Conclusions: These findings suggest that melatonin reduces ethanol intake via specific receptor pathways, supporting its potential use in treating alcohol dependence. Full article

Obsessive-compulsive disorder (OCD) is a chronic mental disorder characterized by distressing thoughts and repetitive behaviors that significantly impair daily functioning and quality of life. Many patients fail to achieve sufficient symptom relief with first-line treatments, such as cognitive-behavioral therapy (CBT) or selective serotonin reuptake inhibitors (SSRIs). Dopaminergic dysregulation has been implicated in the pathophysiology of OCD, providing a rationale for pharmacological augmentation strategies. This article presents a narrative review of the evidence regarding the efficacy, safety, and clinical applicability of antipsychotic agents and emerging pharmacological augmentation approaches, including extended-release methylphenidate (MPH-ER), in SSRI-resistant OCD. A literature search was conducted using PubMed, EBSCO, and Embase databases, with an additional search of Google Scholar, focusing on studies examining pharmacological augmentation in treatment-resistant OCD. Overall, the evidence base is limited by small sample sizes, short follow-up durations, heterogeneous response criteria, and a lack of head-to-head comparisons versus CBT augmentation, which constrains the generalizability of conclusions. Dopamine receptor antagonists, particularly risperidone, as well as the partial agonist aripiprazole, remain the most consistently supported augmentation strategies, while olanzapine and quetiapine may be considered in selected cases. Evidence for MPH-ER is currently limited—supported by one small RCT and two recent case series—and may be considered in carefully selected adults with comorbid ADHD or marked executive dysfunction, although larger controlled studies and long-term safety data are required before firm clinical recommendations can be made. Full article

Background/Objectives: Salidroside, a bioactive phenylethanol glycoside primarily derived from Rhodiola rosea, and its major in vivo metabolite tyrosol exhibit diverse pharmacological activities. However, their direct molecular targets remain poorly defined. Methods: In the present study, an integrated strategy combining transcriptomic profiling, Connectivity Map (CMap) analysis, and multi-level experimental validation was employed. Transcriptomic signatures derived from A549 cells treated with salidroside or tyrosol were queried against the CMap database. Molecular docking, surface plasmon resonance (SPR), and cellular thermal shift assays (CETSA) were performed to predict and validate binding interactions. Functional validation was performed in SH-SY5Y cells. The phosphorylation level of extracellular signal-regulated kinase (ERK), a downstream signaling event of dopamine D2 receptor (DRD2), was detected after salidroside and tyrosol treatment. DRD2 antagonist sulpiride pre-intervention and small interfering RNA (siRNA)-mediated DRD2 knockdown were conducted to verify the receptor dependence of the compounds’ effects. Results: CMap analysis revealed that the transcriptomic signatures of salidroside and tyrosol showed significant similarity to known DRD2 modulators. Molecular docking predicted potential binding interactions between the two compounds and DRD2, which was confirmed by SPR and CETSA to be direct physical binding. Functional studies showed that both compounds rapidly induced DRD2 downstream ERK phosphorylation in SH-SY5Y cells; this effect was abrogated by sulpiride or DRD2 knockdown, indicating DRD2-dependent signaling activation. Conclusions: These findings identify DRD2 as a direct molecular target of salidroside and tyrosol and provide mechanistic insight into their dopaminergic regulatory effects. This study highlights the utility of CMap-guided target discovery combined with rigorous experimental validation for elucidating the molecular mechanisms of natural products. Full article

Background/Objectives: This article is a narrative review that examines the development of attachment from intrauterine life to the first thousand days of a child’s life, integrating psychoanalytic, neuroscientific, genetic, and cross-cultural perspectives. Biological, relational, neurological, and cultural factors interact and shape individual differences in socio-emotional functioning. This paper aims to propose a reinterpretation of early attachment, describing it as both a clinical and relational phenomenon and an adaptive process inscribed in human evolutionary history, according to the Four-Domain Integrative Framework described herein. Methods: The review examined three main areas of evidence: early attachment characteristics, cross-cultural caregiving variations, and genetic and epigenetic mechanisms underlying environmental sensitivity. Results: The review first identified seven characteristics of early attachment (proximity seeking, emotional attunement, intrauterine experiences, maternal holding, security patterns, brain plasticity, and maternal stress) which represent developmental mechanisms that generate individual differences in trust, self-regulation, resilience, and psychopathological vulnerability. Second, cross-cultural variations in six distinct caregiving contexts were examined, demonstrating that secure attachment emerges through culturally specific pathways, differentially influencing motor development, sleep patterns, hypothalamic–pituitary–adrenal axis maturation, and social skills. Finally, the differential susceptibility model was provided through the analysis of five genetic and epigenetic systems (oxytocin receptor gene, serotonin transporter gene, dopamine receptor gene, glucocorticoid receptor methylation, and fetal programming) that modulate environmental sensitivity. Conclusions: Biological, relational, neurological, and cultural factors interact and shape individual differences in socio-emotional functioning. Full article

Parkinson’s disease (PD) is one of the most prevalent and extensively studied neurodegenerative conditions. One of its most challenging clinical manifestations is the emergence of dyskinesias, characterized by involuntary movements that significantly impair patients’ quality of life. Meanwhile, boron, as a trace element, and boron-containing compounds have emerged as active modulators of neurotransmitter systems. To evaluate the effect of aryl-boroxazolidones on parkinsonism, the in vitro neurotoxicity of three boroxazolidones was assessed, along with the effects of two of them in mice with parkinsonism induced by MPTP administration. Two novel compounds demonstrated a limitation of parkinsonism, whereas risperidone reduced the beneficial effect of the tested boroxazolidones. The three boroxazolidones did not induce toxicity in neurons or glial cells at concentrations up to 100 µM. In silico analyses support the ability of BCC to act as ligands of dopamine and serotonin receptors. Taken together, these results suggest that the tested boroxazolidones are promising candidate agents, warranting further exploration for the treatment of PD. Full article

Background: The term dyskinesia describes involuntary movements of the face, body and extremities. Frequently, they appear following and in relation with prior oral long-lasting and high-dose levodopa therapy in Parkinson’s disease patients. Onset of these motion sequences causes patient distress and caregiver embarrassment with declined quality of life. Continuity of nigrostriatal postsynaptic dopamine receptor stimulation delays occurrence of dyskinesia. A pulsatile pattern with temporary too high dopamine receptor excitation promotes manifestation of dyskinesia. Methods: This narrative review describes past pharmacologic approaches for therapy of dyskinesia, such as the principle of continuous dopamine receptor stimulation. Discussion and Conclusions: Novel concepts were tested. They influenced neurotransmission of serotonin and altered stimulation of dopamine receptor subtypes. The translation of successful experimental research outcomes into valuable clinical trial results with consecutive approval of drugs with a new mode of action under the indication “antidyskinetic” repeatedly failed. An exception is the open-channel blocker of the N-methyl-D-aspartate receptor and dopamine reuptake inhibitor amantadine with its moderate dyskinesia-reducing effects, particularly in its extended-release formulation. This antiviral compound also improves impaired motor behavior and reduces “OFF” intervals. Therefore, amantadine is currently experiencing a certain resurgence in regions where its extended-release formulations are marketed for therapy of levodopa-induced dyskinesia. Full article