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Serotonergic psychedelics have attracted considerable interest as promising therapeutic agents. However, the molecular mechanisms linking their acute hallucinogenic-like effects to longer-lasting neuroplastic responses remain incompletely understood, partly because of the scarcity of native neural models suitable for mechanistic studies. Here, we developed a neural stem cell-derived in vitro model capable of differentiating into neuronal and glial lineages and, after characterization, used it to investigate the molecular pharmacology of serotonergic psychedelics. A panel comprising tryptamines, phenethylamines and ergolines, including psychedelic compounds and selected non-psychedelic analogues, was evaluated alongside ketamine and TrkB agonists. Endpoints included dendritogenesis, synaptogenesis, immediate-early gene induction, BDNF expression and lactate production. TrkB silencing abolished dendritogenic responses to serotonergic psychedelics, ketamine and TrkB agonists, whereas 5-HT Show less

Premature ejaculation (PE) accompanied by anxiety or depression is a complex clinical condition at the intersection of male reproductive dysfunction and emotional disorders. Increasing evidence suggests that serotonin (5-HT) and brain-derived neurotrophic factor (BDNF) play central and interrelated roles in its pathogenesis. In this review we examine the bidirectional functions of 5-HT and BDNF in both the reproductive and nervous systems, highlighting their importance in regulating ejaculation, emotional stability, and synaptic plasticity. A comprehensive literature search (2010-2025) was conducted across multiple databases using relevant Medical Subject Headings (MeSH) terms, including pertinent original research and review articles, to synthesize the roles and regulatory pathways of 5-HT and BDNF in PE with comorbid anxiety or depression. We summarize the shared and distinct roles of 5-HT and BDNF in maintaining physiological balance across these systems and focus on their involvement in the major pathological processes underlying PE with anxiety or depression, including neurotransmitter imbalance, neuroendocrine dysregulation, inflammation, and oxidative stress. Furthermore, we outline the related signaling pathways through which 5-HT and BDNF exert their effects and interact. We also evaluate current pharmacological and non-pharmacological interventions targeting these molecules, demonstrating their potential to improve both ejaculatory control and emotional symptoms, and critically appraise selective serotonin reuptake inhibitor (SSRI)-related risks and highlighted the need for individualized dosing and monitoring. Emerging evidence suggests that Traditional Chinese Medicine formulations can extend intravaginal ejaculatory latency and mitigate mood symptoms and may serve as stand-alone or adjunctive options to reduce reliance on selective serotonin reuptake inhibitors (SSRIs). Overall, 5-HT and BDNF are not only deeply involved in the biological mechanisms of PE with comorbid psychological disorders, but also represent promising biomarkers and therapeutic targets, and their integrative neuro-reproductive regulatory functions provide new insights into the diagnosis and treatment of this multifaceted condition. Show less

Early-life stress (ELS) is a key risk factor for adolescent depression. Si-Ni-San (SNS), a classic traditional Chinese medicine formula, has shown antidepressant potential, yet its effects on the dorsal raphe nucleus (DRN)-nucleus accumbens (NAc) serotonergic circuit remain unclear. This study aimed to investigate whether SNS alleviates adolescent depression by restoring DRN-NAc serotonergic circuit function and to identify the serotonin receptor mediating its synaptic effects in the NAc. Firstly, the antidepressant efficacy of SNS was evaluated in a mouse model of ELS. Subsequently, its underlying mechanism was explored through integrated neurophysiological, molecular, and pharmacological analyses. Depressive- and anxiety-like behaviors were assessed using behavioral tests (sucrose preference, tail suspension, forced swim, open field, and elevated plus maze). In vivo electrophysiolog was employed to monitor DRN neuronal activity. Chemogenetic manipulation was employed to regulate the DRN-NAc serotonergic circuit, while 5-HT4R function was assessed through pharmacological intervention and viral knockdown. Synaptic and molecular mechanisms were examined using Western blotting, qPCR, ELISA, and immunofluorescence. SNS alleviated depressive-like behaviors, enhanced neural activity and low-frequency oscillations in the DRN, and restored 5-hydroxytryptamine (5-HT) levels in the NAc. Mechanistically, SNS upregulated tryptophan hydroxylase 2 (TPH2) while downregulating indoleamine 2,3-dioxygenase 1 (IDO1), thus promoting 5-HT synthesis. Critically, the antidepressant effects of SNS were blocked by either chemogenetic inhibition of the DRN-NAc serotonergic circuit or pharmacological blockade of 5-HT4R in the NAc. Meanwhile, the knockdown of 5-HT4R abolished the ameliorative effects of SNS on depressive-like behaviors and associated synaptic remodeling, including the upregulation of brain-derived neurotrophic factor, postsynaptic density protein 95, and mushroom spine density. These results demonstrate that SNS alleviates depressive-like behaviors in adolescent male mice by restoring DRN-NAc serotonergic circuit function, enhancing 5-HT bioavailability, and promoting 5-HT4R-dependent synaptic plasticity in the NAc, revealing a circuit- and receptor-specific therapeutic mechanism. Show less

Major Depressive Disorder (MDD) is a multifactorial psychiatric disease influenced by a combination of genetic and environmental factors. Among the genes linked to MDD, the Melanocortin 1 Receptor (MC1R), Catechol-O-Methyltransferase (COMT), Brain-Derived Neurotrophic Factor (BDNF), and the serotonin transporter (5-HTT) are of particular interest due to their critical roles in stress regulation and neural function. Despite their biological significance, the contribution of specific polymorphisms within these genes to MDD risk remains understudied. This retrospective observational case-control study included 87 Colombian patients diagnosed with MDD according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). The control group comprised Latino/admixed individuals without, sourced from the gnomAD v2.1.1 database. The complete coding region of the MC1R gene and three polymorphisms: 5-HTTLPR Insertion/Deletion 44 bp, BDNF-c.196G>A, and COMT-c.472G>A were genotyped using PCR and Sanger sequencing. The polymorphisms rs885479 and rs4680 were identified as protective factors against MDD, while the polymorphisms rs796296176, rs779504604, rs1805005 were associated with an increased risk of developing MDD (OR:22.87, OR:51.26, OR: 1.97, respectively). Several of the analyzed polymorphisms (rs796296176, rs779504604, rs1805005) increase the risk for MDD. Notably, we provide novel evidence of these polymorphisms in MC1R as a risk to MDD. Show less

A single nucleotide polymorphism in the brain derived neurotrophic factor (BDNF)-encoding gene leads to diminished BDNF signaling resulting from Val66Met and has been linked to obesity. Previous imaging studies regarding the impact of BDNF Val66Met on the central serotonin system, which is involved in behavior, cognition and control of satiety, have not focused on body weight or food-intake related behavior. We revisited a cohort of thirty non-depressed individuals with obesity and 15 normal-weight controls. 29 obese and 13 controls underwent [ Show less

Classic psychedelics, such as psilocybin, lysergic acid diethylamide (LSD), and N,N-dimethyltryptamine (DMT), have emerged as potent modulators of neuroplasticity and metaplasticity in the adult brain, offering novel therapeutic strategies for neuropsychiatric disorders. Recent findings reveal that beyond their transient psychotropic effects, these compounds activate serotonin 5-HT Show less

The serotonin receptor 7 (5-HT7R) has been indicated as a key modulator of neuronal structure and function, playing critical roles in synaptic plasticity, dendritic spine formation, and cytoskeletal remodeling. 5-HT7R activation promotes neurite outgrowth, enhances long-term potentiation (LTP), stimulates local protein synthesis at synapses, and regulates mitochondrial functions, and the mTOR pathway. These properties make the 5-HT7R a compelling candidate for therapeutic intervention in neurodevelopmental disorders characterized by synaptic dysfunctions. Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by the loss of function of the maternal UBE3A gene, resulting in impairments of synaptic plasticity, dendritic spine density, protein synthesis, mitochondrial activity and mTOR signaling. Intriguingly, many of the processes altered in AS are the ones that are positively regulated by 5-HT7R activation. For instance, AS animal models exhibit reduced LTP and altered dendritic morphology and 5-HT7R stimulation enhances synaptic strength and spine formation in the brain of wild type rodents. Moreover, BDNF/TrkB function signaling is impaired and mitochondrial integrity is disrupted in AS and 5-HT7R agonists enhance the altered BDNF/TrkB signalling and restore mitochondrial dysfunctions in Rett syndrome (RTT) mice model. Interestingly, recent evidence demonstrates that pharmacological activation of 5-HT7Rs increases synaptic protein synthesis, restores LTP, enhances dendritic spine density, and improves cognitive function in an AS mouse model. These encouraging results open the way to future studies using neurons and brain organoids generated from iPSCs obtained from AS patients, which represent novel tools in preclinical research. Overall, 5-HT7R stimulation, by counteracting the molecular alterations associated with the loss of UBE3A, may represent a novel approach to restore neural function in the mature brain, leading to translational applications in AS patients, and possibly also in other synaptopathies. Clinical trial number: not applicable. Show less

Preserving brain health is essential to maintaining quality of life and cognitive function with age. Exercise plays an essential role. Aerobic exercise such as running and cycling can enhance brain plasticity through increasing gray matter volume in the cerebellum and temporal lobe, as well as the density of connections in the brain's frontal and motor areas via upregulating brain-derived neurotrophic factor (BDNF) and serotonin systems. Anaerobic exercise, such as weightlifting, primarily increases gray matter volume in the basal ganglia and increases the density of connections in the posterior lobe of the cerebellum. In midlife, aerobic exercise can increase white matter integrity and cortical thickness in primary motor and somatosensory areas, while in older age it improves specific markers of cognitive function, such as episodic memory. With regards to neurodegenerative diseases, aerobic exercise has been linked to improved memory performance and reduced hippocampal atrophy in Alzheimer's disease. In Parkinson disease, aerobic exercise has shown to reduce brain atrophy, improve motor function and cognitive control, while anaerobic exercise improves motor performance and information processing. Overall, both aerobic and anaerobic exercises are integral and complementary to preserving brain health through effects on cognitive function and brain structure. Show less