Search Results (2,653)

Heavy metals are a major toxicological concern due to their adverse effects on human health, particularly in children exposed to contaminated areas. This study evaluated biomarkers of exposure in 253 children aged 6 to 12 from Magangue, Achi, and Arjona (Bolivar, Colombia), analyzing their relationship with neurotoxicity and hematological markers. The mean Pb concentrations at the study sites were 1.98 µg/g (Magangue) > 1.51 µg/g (Achi) > 1.24 µg/g (Arjona). A similar pattern was observed for Cd concentrations for Magangue (0.39 µg/g) > Achi (0.36 µg/g) > Arjona (0.14 µg/g). In contrast, Se concentrations followed a different trend for Arjona (0.29 µg/g) > Magangue (0.21 µg/g) > Achi (0.16 µg/g). The proportion of Se/Pb molar ratios > 1 was higher in Arjona (3.8%) than in Magangue (0.9%) and Achi (2.0%). For Se/Cd ratios, values > 1 were also more frequent in Arjona (70.7%), exceeding 20% in the other two locations. Significant differences were found among locations in red and white blood cell parameters and platelet indices. Neurotransmitter-related biomarkers, including serotonin, monoamine oxidase A (MAO-A), and acetylcholinesterase levels, also varied by location. Principal component analysis showed that Pb and Cd had high loadings on the same component as PLT, WBC, and RDW, and while Se loaded together with HGB, PDW, MCHC, MCH, and MCV, suggesting distinct hematological patterns associated with each element. Multiple linear regression analysis demonstrated a statistically significant inverse association between hair Pb levels and serotonin concentrations. Although MAO-A and Cd showed negative β coefficients, these associations were not statistically significant after adjustment. These findings highlight the potential impact of toxic element exposure on key hematological and neurochemical parameters in children, suggesting early biological alterations that may compromise health and neurodevelopment. Full article

Hormonal contraceptives (HCs) are widely used and generally well tolerated; however, their neuroendocrinological effects remain underappreciated in clinical decision-making. Beyond ovulation suppression, HCs influence brain function by modulating key neurotransmitters such as GABA, serotonin, and dopamine, as well as neurosteroids like allopregnanolone and β-endorphin. These interactions help explain why some users experience mood swings, anxiety, or changes in sexual desire, while others report improvements in well-being. In this narrative review, we explore how different estrogenic and progestin components affect central pathways involved in emotional regulation and cognition. Evidence suggests that estradiol or estetrol-based formulations combined with anti-androgenic progestins like drospirenone or nomegestrol acetate may offer a more favourable neuroendocrine profile, particularly in women with a history of mood disorders or hormonal sensitivity. Understanding these neuroendocrine mechanisms may support more personalized contraceptive choices, particularly in women with mood disorders and hormonal vulnerability. Full article

Glucose is the main source of energy and the source of carbon for the biosynthesis of several molecules, such as neurotransmitters, for most mammalian cells. Therefore, the transport of glucose into cells is very important. There are described three distinct families of glucose transporters: facilitative glucose transporters (GLUTs), sodium-dependent glucose cotransporters (SGLTs), and a uniporter, the SWEET protein. Impaired function and/or expression of these transporters due to, for example, mutations in their genes, may cause severe diseases. Associations with the impaired function of glucose transporters have been described in the case of neurodegenerative diseases (NDs) such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, GLUT1-deficiency syndrome, stroke, and traumatic brain injury. Changes in the presence of glucose transporters may be a cause of NDs, and they may be the effect of NDs. On the other hand, in many cases of neurodegenerative diseases, changes in the expression of glucose transporters may be a targeted therapy in the treatment of patients with these diseases. Full article

Exposure to xenobiotics causes pathophysiological changes in fish, including oxidative stress and neurotoxicity. Here, we describe the biochemical mechanisms underlying oxidative stress (i.e., redox imbalance) and the biochemical markers commonly used to assess its level. Neurotoxicity biomarkers used in fish include behavioral, histological, molecular, neurotransmitter-related, and enzymatic parameters, among which acetylcholinesterase (AChE) activity is the most commonly measured. We therefore also review the changes in AChE activity in fish exposed to common xenobiotics. In most cases, AChE activity decreased in a concentration- and time-dependent manner, although some studies reported no change or even an increase. We emphasize the relevance of all the parameters discussed in the context of fish toxicology studies. Full article

Dietary fiber (DF) is one type of carbohydrate that cannot be digested by the gastrointestinal tract. It is widely recognized as an essential ingredient for health due to its remarkable prebiotic properties. Studies have shown that DF is important in the management of metabolic diseases, such as obesity and diabetes, by regulating the balance of gut microbiota and slowing down the absorption of glucose. It is worth noting that patients with metabolic diseases might suffer from intestinal dysfunction (such as constipation), which is triggered by factors such as the disease itself or medication. This increases the complexity of chronic disease treatment. Although medications are the most common treatment for chronic disease, long-term use might increase the financial and psychological burden. DF as a prebiotic has received significant attention not only in the therapy for constipation but also as an adjunctive treatment in metabolic disease. This review focuses on the application of DF in modulating metabolic diseases with special attention on the effect of DF on intestinal dysfunction. Furthermore, the molecular mechanisms through which DF alleviates intestinal disorders are discussed, including modulating the secretion of gastrointestinal neurotransmitters and hormones, the expression of aquaporins, and the production of short-chain fatty acids. 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

Botulinum neurotoxins (BoNTs) are known to inhibit synaptic transmission by targeting SNARE proteins, but their selectivity toward central excitatory and inhibitory pathways is not yet fully understood. In this study, the interaction of serotypes A (BoNT/A) and B (BoNT/B) with the glutamatergic and GABAergic systems has been investigated using a pharmacological approach in an animal model of inflammatory pain, i.e., the formalin test in mice. BoNTs were administered intracerebroventricularly, three days before testing, followed 15 min before testing by systemic administration of sub-analgesic doses of MK801, an NMDA receptor antagonist, or muscimol, a GABA_A receptor agonist. BoNT/A reduced the second phase of the formalin test without affecting both the first phase and the interphase, suggesting a selective action on excitatory glutamatergic circuits while sparing GABAergic inhibition. Co-administration of MK801 with BoNT/A did not enhance analgesia, and muscimol did not further reduce interphase, confirming preserved GABAergic transmission. In contrast, BoNT/B abolished the interphase, consistent with impaired GABA release. Co-administration of MK801 or muscimol with BoNT/B restored the interphase, indicating compensatory rebalancing of excitatory-inhibitory networks. These results demonstrate that BoNT/A and BoNT/B exert distinct effects on central neurotransmission and support the hypothesis that BoNT/A preferentially targets excitatory synapses, while BoNT/B targets inhibitory synapses. This work contributes to a deeper understanding of anti-inflammatory mechanisms of BoNTs and their selective interaction with central pain pathways. Full article

The balance between physiological, psychological, and environmental factors often shapes human experience. In recent years, research has drawn attention to the gut microbiota as a significant contributor to brain function and emotional regulation. This narrative review examines how changes in gut microbiota may relate to depression. We selected studies that explore the link between intestinal dysbiosis and mood, focusing on mechanisms such as inflammation, vagus nerve signaling, HPA axis activation, gut permeability, and neurotransmitter balance. Most of the available data come from animal models, but findings from human studies suggest similar patterns. Findings are somewhat difficult to compare due to differences in measurement procedures and patient groups. However, several microbial shifts have been observed in people with depressive symptoms, and trials with probiotics or fecal microbiota transplant show potential. These results remain limited. We argue that these interventions deserve more attention, especially in cases of treatment-resistant or inflammation-driven depression. Understanding how the gut and brain interact could help define clearer subtypes of depression and guide new treatment approaches. Full article

The gut microbiota and its interaction with the nervous system through the gut–brain axis (MGB) have been the subject of growing interest in biomedical research. It has been proposed that modulation of microbiota using probiotics could offer a promising therapeutic alternative for mood regulation and the treatment of anxiety and depression disorders. The findings indicate that several probiotic strains, such as Lactobacillus and Bifidobacterium, have demonstrated anxiolytic and antidepressant effects in pre and clinical studies. These effects seem to be mediated by the regulation of the hypothalamic–pituitary–adrenal axis (HPA), the synthesis of neurotransmitters such as serotonin (5-HT) and Gamma-amino-butyric acid (GABA), as well as the modulation of systemic inflammation. However, the lack of standardization in dosing and strain selection, in addition to the scarcity of large-scale clinical studies, limit the applicability of these findings in clinical therapy. Additional research is required to establish standardized therapeutic protocols and better understand the role of probiotics in mental health. The aim of this narrative review is to discuss the relationship between the gut microbiota and the MGB axis in the context of anxiety and depression disorders, the underlying neurobiological mechanisms, as well as the preclinical evidence for the effect of probiotics in modulating these disorders. In this way, an exhaustive search was carried out in scientific databases including PubMed, ScienceDirect, Scopus, and Web of Science. Preclinical research evaluating the effects of different probiotic strains in animal models during chronic treatment was selected, excluding those studies that did not provide access to the full text. Full article

Sleep paralysis (SP), an REM parasomnia, can be characterized as one of the symptoms of narcolepsy. The SP phenomenon involves regaining meta-consciousness by the dreamer during REM, when the physiological atonia of skeletal muscles is accompanied by visual and auditory hallucinations that are perceived as vivid and distressing nightmares. Sensory impressions include personification of an unknown presence, strong chest pressure sensation, and intense fear resulting from subjective interaction with the unfolding nightmare. While the mechanism underlying skeletal muscle atonia is known, the physiology of hallucinations remains unclear. Their complex etiology involves interactions among various membrane receptor systems and neurotransmitters, which leads to altered neuronal functionality and disruptions in sensory perception. According to current knowledge, serotonergic activation of 5-hydroxytryptamine-receptor-2A (5-HT2A)-associated pathways plays a critical role in promoting hallucinogenesis during SP. Furthermore, they share similarities with psychedelic-substance-induced ones (i.e., LSD, psilocybin, and 2,5-dimethoxy-4-iodoamphetamine). These compounds also target the 5-HT2A receptor; however, their molecular mechanism varies from serotonin-induced ones. The current review discusses the intracellular signaling pathways responsible for promoting hallucinations in SP, highlighting the critical role of β-arrestin-2. We propose that the β-arrestin-2 signaling pathway does not directly induce hallucinations but creates a state of network susceptibility that facilitates their abrupt emergence in sensory areas. Understanding the molecular basis of serotonergic hallucinations and gaining better insight into 5-HT2A-receptor-dependent pathways may prove crucial in the treatment of multifactorial neuropsychiatric disorders associated with the dysfunctional activity of serotonin receptors. Full article

Background: Anabolic–androgenic steroids (AASs) are commonly used for performance enhancement but have been linked to significant neurobiological consequences. This review explores the impact of AASs on neurochemical pathways, cognitive function, and psychiatric disorders, highlighting their potential neurotoxicity. Methods: A narrative review of current literature was conducted to examine AASs-induced alterations in neurotransmitter systems, structural and functional brain changes, and associated psychiatric conditions. The interplay between AASs use and other substances was also considered. Results: Chronic AASs exposure affects serotonin and dopamine systems, contributing to mood disorders, aggression, and cognitive deficits. Structural and functional changes in the prefrontal cortex and limbic regions suggest long-term neurotoxicity. AASs use is associated with increased risks of depression, anxiety, and psychosis, potentially driven by hormonal dysregulation and neuroinflammation. Co-occurring substance use exacerbates neurocognitive impairments and behavioral disturbances. Discussion: While evidence supports the link between AASs use and neurotoxicity, gaps remain in understanding the precise mechanisms and long-term effects. Identifying biomarkers of brain damage and developing targeted interventions are crucial for mitigating risks. Increased awareness among medical professionals and policymakers is essential to address AASs-related neuropsychiatric consequences. Conclusions: AASs abuse poses significant risks to brain health, necessitating further research and prevention efforts. Evidence-based strategies are needed to educate the public, enhance early detection, and develop effective interventions to reduce the neuropsychiatric burden of AASs use. Full article

The endocannabinoid system (ECS) is a complex neuromodulatory network involved in maintaining physiological balance through interactions with various neurotransmitter and hormonal pathways. Its key components—cannabinoid receptors (CBRs)—are activated by endogenous ligands and exogenous cannabinoids such as those found in the Cannabis sativa plant. Although cannabinoids like cannabidiol (CBD) have garnered interest for their potential therapeutic effects, evidence regarding their safety, particularly for reproductive health, remains limited. This review summarizes the structure and molecular mechanisms of the ECS, its role in reproductive physiology—including its interactions with the hypothalamic–pituitary–gonadal axis (HPG axis), gametogenesis, implantation, and lactation—and the possible consequences of cannabinoid exposure for fertility. In addition, we focus on the involvement of the ECS and cannabinoids in breast cancer, highlighting emerging evidence on their dual role in tumor progression and therapy. These insights emphasize the need for further research to better define the therapeutic potential and risks associated with cannabinoid use in reproductive health and breast cancer. Full article

Sensory dysregulation represents a core challenge in autism spectrum disorder (ASD), affecting perception, behavior, and adaptive functioning. The brain’s ability to reorganize, known as neuroplasticity, serves as the basic principle for therapeutic interventions targeting these deficits. Neuroanatomical mechanisms include altered connectivity in the sensory and visual cortices, as well as in the limbic system and amygdala, while imbalances of neurotransmitters, in particular glutamate and gamma-aminobutyric acid (GABA), contribute to atypical sensory processing. Traditional therapies used in sensory integration are based on the principles of neuroplasticity. Increasingly, new treatments use this knowledge, and modern therapies such as neurofeedback, transcranial stimulation, and immersive virtual environments are promising in modulating neuronal circuits. However, further research is needed to optimize interventions and confirm long-term effectiveness. This review discusses the role of neuroplasticity in the etiopathogenesis of sensory integration deficits in autism spectrum disorder. The neuroanatomical and neurotransmitter basis of impaired perception of sensory stimuli is considered, and traditional and recent therapies for sensory integration are discussed. Full article

Konjac glucomannan (KGM) is a natural polysaccharide polymer. It is degraded by gut microbiota-derived β-mannanase into small-molecule nutrients, which exert diverse physiological regulatory effects. As a prebiotic, KGM modulates gut microbiota composition. It selectively fosters the proliferation of beneficial commensals and suppresses potential pathogens, thereby alleviating microbiota-related disorders. Moreover, microbiota fermentation of KGM produces metabolites. Short-chain fatty acids (SCFAs) are particularly notable among these metabolites. They exert multifaceted beneficial effects, including metabolic regulation, intestinal barrier strengthening, and neuroprotective functions. These effects are mediated through inhibition of inflammatory pathways (e.g., NF-κB, MAPK), modulation of lipid metabolism genes (e.g., CD36), and regulation of neurotransmitters (e.g., GABA, 5-HT). This highlights KGM’s therapeutic potential for metabolic, inflammatory, and neurodegenerative diseases. Current clinical use is limited by dose-dependent adverse effects and interindividual response variability, which stem from different microbial communities. This necessitates personalized dosage strategies. Despite these limitations, KGM as a prebiotic polysaccharide exhibits multifaceted bioactivity. Current evidence suggests its potential to synergistically modulate metabolic pathways, gut microbiota composition, immune cell signaling, and neuroendocrine interactions. This highlights its promise for developing novel therapeutic interventions. Full article

ATP13A2 is a lysosomal polyamine transporter with loss of function mutations linked to multiple neurodegenerative disorders including Parkinson’s disease (PD). Knockout of ATP13A2 in mice leads to age-related sensorimotor impairments and in the brain lipofuscinosis, gliosis, and modest alpha-synuclein (αSyn) pathology. However, few studies have included ATP13A2 heterozygous mice as a comparison. In the present study, the effect of reduced or complete loss of ATP13A2 function on behavior, αSyn, gliosis, dopamine, and polyamines were determined in mice. Male and female ATP13A2 wildtype (WT), heterozygous (Het), and knockout (KO) mice were assessed behaviorally at 3, 12, and 18 months of age. In the brain, αSyn, phosphorylated αSyn, and GFAP were measured in the prefrontal cortex, striatum, ventral midbrain, and cerebellum. Polyamine and neurotransmitter analyses were performed in the same brain regions. Similar to previous studies, KO mice developed motor impairments and widespread gliosis in the brain. In addition, polyamine content was altered in Het and KO mice. In contrast, Het mice showed impairments in cognitive function and an age-related increase in αSyn in the brain. These results indicate potentially different pathological mechanisms when ATP13A2 is reduced compared to when it is knocked out and may have important implications for disease modification in synucleinopathies including PD. Full article