Search Results (441)

Huntington disease’s (HD) is a neurodegenerative disorder caused by the expansion of a polyglutamine region (PolyQ) within the huntingtin protein (HTT). Mutated huntingtin (mHTT) is cytotoxic, particularly for striatal medium spiny neurons (MSNs), whose degeneration is the hallmark of HD. Autophagy inducers currently available promote the clearance of toxic proteins. However, due to their low selectivity and the possibility that prolonged autophagy hampers essential processes in unaffected cells, researchers have questioned their benefits in neurodegenerative diseases. Since MSNs express dopamine receptors D2 (DRD2) and D3 (DRD3) and DRD2/DRD3 agonists may activate autophagy, here, we explored how healthy and mHTT-challenged cells respond to prolonged DRD2/DRD3 agonist treatment. Autophagy activation and its effects on mHTT/polyQ clearance were studied in R6/1 mice (a genetic model of HD), their wild-type littermates, and DRD2- and DRD3-HEK cells expressing a pathogenic (Q74) and a non-pathogenic (Q23) polyQ fragment of mHTT treated with the DRD2/DRD3 agonist pramipexole. Two forms of DRD3-mediated autophagy were found: a transient mTORC1-dependent in WT mice and Q23-DRD3-HEK cells and a persistent AMPK-ULK1-activated in R6/1 mice and Q74-DRD3-HEK cells. This also promoted a robust clearance of soluble mHTT/polyQ and neuroprotection in striatal neurons and DRD3-HEK cells. The findings indicate that DRD3-induced autophagy may be a safe, disease-modifying intervention in HD patients. Full article

Both a shortage and an excess of dopamine (DA) in the prefrontal cortex and striatum result in their decreased functions, and the relationship between the DA levels and their functions exhibits an inverted-U shape. Increased DA transmission via dose reduction in the currently used antipsychotics may improve the activation of DA-related symptoms in schizophrenia; these include delusions and auditory hallucinations caused by increased DA release. In this case, reducing the dose of the antipsychotic may be a treatment option for relapse in patients with schizophrenia who are already on high doses of antipsychotics and find it difficult to further increase the dose. A total of 54 inpatients with schizophrenia receiving high-dose antipsychotic therapy were randomly assigned to either the halved-dose group or the high-dose group (symptomatic treatment). The study compared the time from relapse to improvement between the two groups. In the halved-dose group, the period until relapse improvement ranged from 1 to 3 weeks, while the high-dose group experienced improvement in 4 to 9 weeks, and a significant difference was observed between the two groups using Kaplan–Meier survival analysis (p < 0.001). Full article

Dysregulated dopamine (DA) release in the mesocorticolimbic circuit is noted in Parkinson’s disease (PD) patients with impulsive and compulsive behaviors (ICBs). However, the effect of acute DA release on mood, the localization of this process, and the phenotypic differences in patients with ICB remain unknown. We applied a placebo-controlled dextro-amphetamine (dAMPH) study in 20 PD patients: 10 with ICBs (PD-ICB) and 10 without (PD-C). Subjective mood experiences were measured with well-described self-reported measures including the Positive and Negative Affect Scale (PANAS), Drug Effects Questionnaire (DEQ), and Amphetamine Interview Rating Scale (AIRS). D2-like receptor availability was measured as non-displaceable binding potential (BP_ND) using PET imaging with the high-affinity D2/3 receptor ligand [¹⁸F]-fallypride. Among all the subjects, dAMPH increased the PANAS positive, DEQ feel, DEQ high, and AIRS total scores. Increases in the PANAS positive and AIRS total scores were greater in the PD-ICB cohort. A mixed-effects model correlated these questionnaire changes with dAMPH-induced reductions in BP_ND in the ventral striatum (VS), caudate, amygdala, and caudo-medial orbitofrontal cortex. The baseline caudate, VS, and amygdala BP_ND positively correlated with lower on-dAMPH PANAS positive scores. Elevated mood symptoms of acute dAMPH administration in PD are linked to DA release in the mesocorticolimbic regions. Distinctions in behavioral effects among PD-ICB subjects emphasize that dysregulated striatal and extra-striatal DA-ergic networks alter mood responses to stimulated DA release and may also contribute to behavioral changes resulting from DA-targeting therapies in PD. Full article

Serotonin 5HT_1A receptors may be affected in neurodegeneration, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). Using the selective 5HT_1A receptor positron emission tomography (PET) imaging agent, [¹⁸F]mefway, autoradiographic studies from postmortem human brains of AD, PD, and cognitively normal (CN) subjects were carried out. Levels of [¹⁸F]mefway binding were compared with monoamine oxidase A (MAO-A) measured using [¹⁸F]FAZIN3 binding and dopamine D2/D3 receptors measured using [¹⁸F]fallypride binding in the same subjects. Autoradiograms of brain sections of the anterior cingulate and corpus callosum from CN, PD, and AD subjects (n = 6 in each group) were analyzed. Significant increased binding of [¹⁸F]mefway was found in the AD (+30%) and PD (+11%) brains compared to CN brains. This increase positively correlated to increased [¹⁸F]FAZIN3 binding, suggesting greater 5HT_1A receptor availability when MAO-A levels are higher. Differences in [¹⁸F]fallypride binding in the three groups were not significant. Our results support the finding that the availability of 5HT_1A receptors in AD and PD is elevated in the anterior cingulate cortex and is negatively correlated with MAO-A. This upregulation may potentially be a response to lower serotonin levels due to the increased levels of MAO-A activity in this brain region or other neuroinflammatory changes. Thus, 5HT_1A receptors may be a potential target for diagnostic and therapeutic approaches for AD and PD. Full article

Background/Objectives: Montelukast (MLK), a leukotriene receptor antagonist, has been associated with neuropsychiatric side effects. This study aimed to rationally modify MLK’s structure to reduce these risks by optimizing its interactions with dopamine D2 (DRD2) and serotonin 5-HT1A receptors using computational molecular simulation techniques. Methods: A library of MLK derivatives was designed and screened using structural similarity analysis, molecular docking, molecular dynamics (MD) simulations, MM/PBSA binding free energy calculations, and ADME-Tox predictions. Structural similarity analysis, based on Tanimoto coefficient fingerprinting, compared MLK derivatives to known neuropsychiatric drugs. Docking was performed to assess initial receptor binding, followed by 100 ns MD simulations to evaluate binding stability. MM/PBSA calculations quantified binding affinities, while ADME-Tox profiling predicted pharmacokinetic and toxicity risks. Results: Several MLK derivatives showed enhanced DRD2 and 5-HT1A binding. MLK_MOD-42 and MLK_MOD-43 emerged as the most promising candidates, exhibiting MM/PBSA binding free energies of −31.92 ± 2.54 kcal/mol and −27.37 ± 2.22 kcal/mol for DRD2 and −30.22 ± 2.29 kcal/mol and −28.19 ± 2.14 kcal/mol for 5-HT1A, respectively. Structural similarity analysis confirmed that these derivatives share key pharmacophoric features with atypical antipsychotics and anxiolytics. However, off-target interactions were not assessed, which may influence their overall safety profile. ADME-Tox analysis predicted improved oral bioavailability and lower neurotoxicity risks. Conclusions: MLK_MOD-42 and MLK_MOD-43 exhibit optimized receptor interactions and enhanced pharmacokinetics, suggesting potential neuropsychiatric applications. However, their safety and efficacy remain to be validated through in vitro and in vivo studies. Until such validation is performed, these derivatives should be considered as promising candidates with optimized receptor binding rather than confirmed safer alternatives. Full article

Dopamine D₃ receptor (D₃R) is a key receptor for regulating motor, cognitive, and other functions. In this study, 50 2-phenylcyclopropylmethylamine (PCPMA) derivatives with good selectivity for D₃R were investigated using a three-dimensional quantitative structure–activity relationship (3D-QSAR) method. The CoMFA and CoMSIA model results showed good predictive ability, as evidenced by high r² and q² values. 3D-QSAR results showed that steric, electrostatic, and hydrophobic fields played important roles in the binding of PCPMAs to D₃R. Based on above results, four novel PCPMAs were designed, which were predicted to have a stronger affinity with D₃R. Molecular docking combined with 300 ns molecular dynamics simulations were performed to reveal the mode of interaction between D₃R and PCPMAs. Additionally, a combination of free energy calculations and energy decomposition results indicated strong interaction between the ligands and residues in the binding pocket of the D₃ receptor. This work provides suggestions for exploring more selective D₃R ligands, and this theoretical framework also lays the foundation for future experimental investigations to evaluate the pharmacological characteristics and binding affinities of novel derivatives. Full article

Bioelectric membrane potentials regulate cellular growth, differentiation, and movement. Disruptions in bioelectric signaling are strongly linked to cancer development, as abnormal membrane potentials and ion channel activity can drive tumor progression. In breast cancer, ion channel dysfunction and neuroreceptor-related pathways play significant roles in the cell cycle, epithelial–mesenchymal transition, angiogenesis, inflammation, the tumor microenvironment, and tumor progression. Neuroreceptors are critical not only in initiating and advancing cancer but also in conferring resistance to treatments. Neuroreceptors also play a key role, with dopamine receptor D2 activation reducing breast tumor growth by 40% in preclinical models, while serotonin signaling has been shown to promote epithelial–mesenchymal transition (EMT), increasing invasiveness. Advances in understanding these biological mechanisms could lead to more cost-effective and less invasive therapeutic strategies to treat tumors. This review explores the expanding evidence connecting bioelectric activity to breast cancer, focusing on neuroreceptor pharmacology as a transformative therapeutic approach. Examining the modulation of bioelectricity through neuroreceptor pharmacology to influence breast cancer progression and integrating these insights into therapeutic development offers a promising path for addressing treatment challenges and improving precision in managing aggressive cancer subtypes. Full article

Objective: To narratively review currently available antidepressants and future potential antidepressants as monotherapy for the treatment of depressive disorders. Methods: Selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), dopamine reuptake inhibitor (bupropion), tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOIs) were reviewed according to the results from Sequenced Treatment Alternatives to Relieve Depression (STAR*D) Study and systematic reviews. For the rest of the antidepressants, a PubMed/Medline search was conducted with priority for systematic reviews. For drugs in development for depressive disorders, PubMed, Google, and Clinicaltrials.gov databases were used. Results: The STAR*D Study demonstrated that sertraline, venlafaxine, and bupropion monotherapy had similar efficacy in patients with major depressive disorder (MDD) who failed citalopram. A network meta-analyses of randomized, placebo-controlled trials found that SSRIs, SNRIs, bupropion, TCAs, mirtazapine, and agomelatine had similar relative efficacy compared to placebo, but had different acceptability. Gepirone had more failed/negative studies and smaller effect size relative to placebo compared to other antidepressants. The combination of dextromethorphan and bupropion, ketamine infusion, and intranasal esketamine had faster onset of action but similar effect size compared to monoamine-based antidepressants as monotherapy. Brexanolone and zuranolone are effective in postpartum depression (PPD), but the effect size of zuranolone in MDD as monotherapy or adjunctive therapy was very small. Psychedelics, glutamate receptor-related agents, kappa opioid receptor antagonists, orexin receptor antagonists, new anti-inflammatory agents, and biomarker-based antidepressant therapy have been under investigation for depressive disorders. Psychedelics showed faster onset of action, large effect size, and long durability. Conclusions: Monoamine-based antidepressants likely continue to be the mainstream antidepressants for depressive disorder. NMDA receptor antagonists and neurosteroid antidepressants will play a bigger role with the improvement of accessibility. Psychedelics may become a game changer if phase III studies validate their efficacy and safety in depressive disorders. Full article

Methamphetamine (METH) use disorder (MUD) is a public health catastrophe. Herein, we used a METH self-administration model to assess behavioral responses to the dopamine receptor D1 (DRD1) antagonist, SCH23390. Differential gene expression was measured in the dorsal striatum after a 30-day withdrawal from METH. SCH23390 administration reduced METH taking in all animals. Shock Resistant (SR) rats showed greater incubation of METH seeking, which was correlated with increased Creb1, Cbp, and JunD mRNA expression. Cytoplasmic polyadenylation element binding protein 4 (Cpeb4) mRNA levels were increased in shock-sensitive (SS) rats. SS rats also showed increased protein levels for cleavage and polyadenylation specificity factor (CPSF) and germ line development 2 (GLD2) that are CPEB4-interacting proteins. Interestingly, GLD2-regulated GLUN2A mRNA and its protein showed increased expression in the shock-sensitive rats. Taken together, these observations identified CPEB4-regulated molecular mechanisms acting via NMDA GLUN2A receptors as potential targets for the treatment of METH use disorder. Full article

Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by the selective loss of dopaminergic (DA) neurons in the midbrain. While dopamine precursor levodopa and D2 receptor agonists are commonly used to alleviate PD symptoms, these treatments do not halt or reverse disease progression. Thus, developing effective neuroprotective strategies remains a critical goal. In this study, we explored neuroprotective mechanisms in a Drosophila primary neuronal culture model of PD, created by administering the environmental toxin rotenone. Using the chemogenetic DREADD (designer receptors exclusively activated by designer drugs) system, we selectively activated cAMP signaling in DA neurons within the rotenone-induced model. Our results demonstrate that increasing cAMP signaling via Gs-coupled DREADD (rM3Ds) is protective against DA neurodegeneration. Furthermore, overexpression of the catalytic PKA-C1 subunit fully rescued DA neurons from rotenone-induced degeneration, with this effect restricted to DA neurons where PKA-C1 was specifically overexpressed. These findings reveal that cAMP-PKA signaling activation is neuroprotective in DA neurons against rotenone-induced degeneration, offering promising insights for developing targeted therapeutic strategies to slow or prevent PD pathology progression. Full article

Nicotine addiction is a serious global public health problem, so there is an urgent necessity to develop novel effective smoking cessation treatments with fewer adverse effects. Spontaneous behavioral sensitization induced by repeated intermittent exposure to the addictive substance represents a classical animal model of addiction research. A significant contributor to nicotine addiction is its interaction with α6β2* nAChRs located on midbrain dopaminergic neurons, which leads to an increase in dopamine (DA) release. α-Conotoxin (α-CTx) TxIB is a novel potent antagonist of the α6/α3β2β3* nAChRs, with an IC50 value of 28.4 nM developed by our group. In this study, we aimed to investigate the effectiveness of α-CTx TxIB in countering nicotine-induced behavioral sensitization and moderating the impact of nicotine on dopamine accumulation in the midbrain. Our results demonstrated that repeated nicotine administration remarkably elevated the locomotor activity of mice, including the number of entries, average speed, and total distance traveled, which could be effectively attenuated by α-CTx TxIB intervention in a dose-dependent manner (1 nmol and 5 nmol TxIB per mouse). Furthermore, 5 nmol α-CTx TxIB significantly reduced the nicotine-elevated DA and norepinephrine (NE) levels in the ventral tegmental area (VTA) and nucleus accumbens (NAc) of mice. 5 nmol α-CTx TxIB also markedly decreased the expression of critical proteins such as the dopamine transporter (DAT), N-methyl-D-aspartic acid receptor (NMDAR), and c-Fos in the NAc and prefrontal cortex (PFC) of the nicotine-exposed mice. This research provided the first compelling evidence that α-CTx TxIB attenuated nicotine-induced locomotor sensitization and inhibited the nicotine-induced dopamine elevation in mice. These results open up new avenues for exploring the therapeutic potential of α-CTx TxIB in the treatment of nicotine addiction. Full article

Background: Dopamine (DA) is an important neurotransmitter that is widely present in the central nervous system. DA plays a crucial regulatory role in mammalian emotion, endocrine function, and reproduction through the activation of dopamine receptors. We compared the transcriptomes of hypothalamic tissues from Kazakh sheep during the nonbreeding season of anoestrus and during the nutrient-induced nonbreeding season of oestrus. Our research findings suggest that the dopamine receptor D1 (DRD1) gene may be a candidate gene for the regulation of sheep oestrus. However, the underlying mechanism through which DRD1 regulates sheep oestrus is still poorly understood. Methods: In the present study, the expression of DRD1 mRNA in the hypothalamus of oestrous Kazakh sheep was significantly greater than that in the anoestrous phase. Immunohistochemical staining revealed that DRD1 was more widely expressed in hypothalamic tissue and was more highly expressed during oestrus than during anoestrus. Hypothalamic neuron experiments further indicated that DRD1 affects the expression of GnRH through dopamine synapses and calcium signalling pathways. Results: moreover, the overexpression of the DRD1 gene promoted the secretion of GnRH, while knocking down the DRD1 gene reduced the secretion of GnRH. Conclusions: The present study revealed that the DRD1 gene plays a crucial regulatory role in the secretion of the hormone GnRH in the hypothalamus of Kazakh sheep. Full article

Valerian possesses a multitude of pharmacological effects, including sedative and hypnotic properties, antihypertensive effects, antibacterial activity, and liver protection. Insomnia, one of the most prevalent disorders in contemporary society, significantly impacts people’s daily lives. This study aims to explore the anti-insomnia effects of valerian volatile oil (VVO) and investigate its potential mechanism of action through chemical analysis, network pharmacology, molecular docking, molecular dynamics simulations, and experimental validation. Through gas chromatography–mass spectrometry (GC-MS) analysis and drug-likeness screening, we identified 38 active compounds. Network pharmacology studies revealed that these 38 compounds might affect 103 targets associated with insomnia, such as monoamine oxidase B (MAOB), dopamine receptor D2 (DRD2), monoamine oxidase A (MAOA), interleukin 1β (IL1B), solute carrier family 6 member 4 (SLC6A4), prostaglandin-endoperoxide synthase 2 (PTGS2), and 5-hydroxytryptamine receptor 2A (HTR2A), which contribute to regulating the neuroactive ligand–receptor interaction, 5-hydroxytryptaminergic synapse, and calcium signaling pathways. The results of the molecular dynamics simulations indicated that bis[(6,6-dimethyl-3-bicyclo[3.1.1]hept-2-enyl)methyl] (E)-but-2-enedioate exhibited a stabilizing interaction with MAOB. The animal studies demonstrated that gavage administration of a high dose (100 mg/kg) of VVO significantly diminished autonomous activity, decreased sleep latency, and extended sleep duration in mice. Furthermore, the results of the Western blot experiment indicated that VVO interacts with MAOB, resulting in decreased expression levels of MAOB in the cerebral cortex. This study demonstrates the protective mechanism of VVO against insomnia through chemical analysis, network pharmacology, and experimental validation and extends the possible applications of VVO, which is a potential therapeutic ingredient for use in insomnia treatment. Full article

Background: Sorting nexin 19 (SNX19) is important in the localization and trafficking of the dopamine D₁ receptor (D₁R) to lipid raft microdomains. However, the interaction between SNX19 and the lipid raft components caveolin-1 or flotillin-1 and, in particular, their roles in the cellular endocytosis and cell membrane trafficking of the D₁R have not been determined. Methods: Caveolin-1 and flotillin-1 motifs were analyzed by in silico analysis; colocalization was observed by confocal immunofluorescence microscopy; protein-protein interaction was determined by co-immunoprecipitation. Results: In silico analysis revealed the presence of putative caveolin-1 and flotillin-1 binding motifs within SNX19. In mouse and human renal proximal tubule cells (RPTCs), SNX19 was localized mainly in lipid rafts. In mouse RPTCs transfected with wild-type (WT) Snx19, fenoldopam (FEN), a D₁-like receptor agonist, increased the colocalization of SNX19 with caveolin-1 and flotillin-1. FEN also increased the co-immunoprecipitation of SNX19 with caveolin-1 and flotillin-1, effects that were prevented by SCH39166, a D₁-like receptor antagonist. The FEN-mediated increase in the residence of SNX19 in lipid rafts and the colocalization of the D₁R with caveolin-1 and flotilin-1 were attenuated by the deletion of a caveolin-1 (YHTVNRRYREF) (ΔCav1) or a flotillin-1 (EEGPGTETETGLPVS) (ΔFlot1) binding motif. The FEN-mediated increase in intracellular cAMP production was also impaired by the deletion of either the flotillin-1 or caveolin-1 binding motif. Nocodazole, a microtubule depolymerization inhibitor, interfered with the FEN-mediated increase in the colocalization between SNX19 and D₁R. Conclusion: SNX19 contains caveolin-1 and flotillin-1 binding motifs, which play an important role in D₁R endocytosis and signaling. Full article

Despite recent advancements in radiotherapy for Diffuse Intrinsic Pontine Glioma (DIPG), the prognosis of this disease remains poor, highlighting the need for new treatment strategies to improve outcomes. Adding stereotactic biopsy to the diagnostic process for children with DIPG has been crucial in improving the management of this disease. Indeed, the discovery of the H3K27M mutation as a key driver of DIPG has led to the development of new drugs that are more effective than traditional ones. These include nimotuzumab (an anti-EGFR drug) and vinorelbine (a semisynthetic vinca alkaloid) in combination, Panobinostat (a histone deacetylase inhibitor), ONC201 (a drug that blocks the dopamine receptor D2 and inactivates Akt and ERK kinases), and chimeric antigen receptor (CAR) T cells. In terms of local therapy, identifying the H3K27M mutation can help us explore how genetic changes affect treatment response, recurrence patterns, and survival. Beyond the time to first recurrence, specific patterns of tumor recurrence, like leptomeningeal spread, can influence treatment plans. For example, radiotherapy can be adjusted in terms of doses and volumes, based on tumor aggressiveness. Because the H3K27M mutation is linked to higher malignancy, a slightly higher dose could be used for the second round of local irradiation. Additionally, irradiating the entire craniospinal axis could help control both local and leptomeningeal disease. Full article