Monoamine Oxidase Research Articles

Tannins-enriched fraction of TeMac™ protects against aluminum chloride induced Alzheimer's disease-like pathology by modulating aberrant insulin resistance and alleviating oxidative stress in diabetic rats

Ethnopharmacological relevanceAlzheimer's disease is the most common neurodegenerative disease with therapeutic limitations. Insulin resistance plays a role in the progression of Alzheimer's disease. Therapies that modulate insulin secretion and signaling, as well as oxidative stress in the brain are now being investigated for their potential role in the prevention of Alzheimer's disease (AD). Terminalia macroptera (Combretaceae) is a plant that different parts have been used traditionally for the treatment of metabolic and neurological conditions. Previous study has indicated that the crude extract exhibit anti-diabetic property. In addition, the plant is a rich source of tannins, phenolic acids, flavonoids, triterpenes. However, there is no study on its protective effect against biochemical alterations of AD in diabetic rats. Aim of the studyThe present research study investigated the neuroprotective effects of TeMac™ on Alzheimer-like pathology induced by aluminum chloride (AlCl3) in diabetic rats. MethodsA phytochemical analysis of TeMac™ was carried out to quantify tannins. The potential effect of the tannins-enriched fraction (TEF) of TeMac™ to prevent the formation of senile plaques was conducted by its ability to inhibit the activities of β-secretase (EC 3.4.23.46), monoamine oxidase A (EC 1.4.3.4) and the fibrillation of Aβ. A diabetic model was induced from female Wistar rats by a single intraperitoneal injection of streptozotocin (STZ, 35 mg/kg BW). After that, the blood glucose level was measured to confirm the induction of diabetes. Three days after induction, animals received AlCl3 (75 mg/kg BW) alone (AD control) or concomitantly with 400 mg/kg BW of TEF of TeMac™ or 5 mg/kg BW Daonil by daily gavage for 42 days. At the end of the experiment, rats were sacrificed, blood and brains were collected. The levels of amyloid fibrils, glucose, albumin and the activities of DPP4, β-secretase and phosphatase, and markers of oxidative stress in the brain were assessed. ResultsTEF of TeMac™ displays a potential ability to inhibit the activities of β-secretase, monoamine oxidase, and Aβ fibrillation. Treatment with TEF of TeMac™ significantly inhibited DPP4 and BACE1 activities and reduced brain glucose and amyloid fibril levels, and improved cerebral albumin levels and modulated oxidative stress markers. ConclusionOur findings indicate that TEF of TeMac™ prevents Alzheimer's-type pathology linked to insulin resistance in rats. TEF of TeMac™ may be a potential drug candidate for the treatment of diabetes-associated cognitive impairment.

Uncovering the Elusive Structures and Mechanisms of Prevalent Antidepressants

AbstractMost treatments to alleviate major depression work by either inhibiting human monoamine transporters, vital for the reuptake of monoamine neurotransmitters, or by inhibiting monoamine oxidases, which are vital for their degradation. The analysis of the experimental 3D structures of those antidepressants in their drug formulation state is key to precision drug design and development. In this study, microcrystal electron diffraction (MicroED) is applied to reveal the atomic 3D structures for the first time of five of the most prevalent antidepressants (reboxetine, pipofezine, ansofaxine, phenelzine, and bifemelane) directly from the commercially available powder of the active ingredients. Their modes of binding are investigated by molecular docking, revealing the essential contacts and conformational changes into the biologically active state. This study underscores the combined use of MicroED and molecular docking to uncover elusive drug structures and mechanisms to aid in further drug development pipelines.

Impulse control disorders in Parkinson’s disease: a national Swedish registry study on high-risk treatments and vulnerable patient groups

BackgroundImpulse control disorders (ICDs) are known psychiatric conditions in Parkinson’s disease (PD), especially as a side effect of antiparkinsonian therapy. Screening for vulnerable patients and avoiding high-risk treatments can be...

Early Astrocytic Dysfunction Is Associated with Mistuned Synapses as well as Anxiety and Depressive-Like Behavior in the AppNL-F Mouse Model of Alzheimer's Disease.

Alzheimer's disease (AD) is the most common neurodegenerative disease. Unfortunately, efficient and affordable treatments are still lacking for this neurodegenerative disorder, it is therefore urgent to identify new pharmacological targets. Astrocytes are playing a crucial role in the tuning of synaptic transmission and several studies have pointed out severe astrocyte reactivity in AD. Reactive astrocytes show altered physiology and function, suggesting they could have a role in the early pathophysiology of AD. We aimed to characterize early synaptic impairments in the AppNL-F knock-in mouse model of AD, especially to understand the contribution of astrocytes to early brain dysfunctions. The AppNL-F mouse model carries two disease-causing mutations inserted in the amyloid precursor protein gene. This strain does not start to develop amyloid-β plaques until 9 months of age. Thanks to electrophysiology, we investigated synaptic function, at both neuronal and astrocytic levels, in 6-month-old animals and correlate the synaptic activity with emotional behavior. Electrophysiological recordings in the hippocampus revealed an overall synaptic mistuning at a pre-plaque stage of the pathology, associated to an intact social memory but a stronger depressive-like behavior. Astrocytes displayed a reactive-like morphology and a higher tonic GABA current compared to control mice. Interestingly, we here show that the synaptic impairments in hippocampal slices are partially corrected by a pre-treatment with the monoamine oxidase B blocker deprenyl or the fast-acting antidepressant ketamine (5 mg/kg). We propose that reactive astrocytes can induce synaptic mistuning early in AD, before plaques deposition, and that these changes are associated with emotional symptoms.

New Acacetin Glycosides and Other Phenolics from Agastache Foeniculum and Their Influence on Monoamine Oxidase A and B

New Acacetin Glycosides and Other Phenolics from Agastache Foeniculum and Their Influence on Monoamine Oxidase A and B

Repetitive Administration of Low-Dose Lipopolysaccharide Improves Repeated Social Defeat Stress-Induced Behavioral Abnormalities and Aberrant Immune Response.

Repetitive exposure of innate immune cells to a subthreshold dosage of endotoxin components may modulate inflammatory responses. However, the regulatory mechanisms in the interactions between the central nervous system (CNS) and the immune system remain unclear. This study aimed to investigate the effects of lipopolysaccharide (LPS) preconditioning in repeated social defeat stress (RSDS)-induced abnormal immune responses and behavioral impairments. This study aimed to elucidate the mechanisms that underlie the protective effects of repeated administration of a subthreshold dose LPS on behavioral impairments using the RSDS paradigm. LPS preconditioning improved abnormal behaviors in RSDS-defeated mice, accompanied by decreased monoamine oxidases and increased glucocorticoid receptor expression in the hippocampus. In addition, pre-treated with LPS significantly decreased the recruited peripheral myeloid cells (CD11b+CD45hi), mainly circulating inflammatory monocytes (CD11b+CD45hiLy6ChiCCR2+) into the brain in response to RSDS challenge. Importantly, we found that LPS preconditioning exerts its protective properties by regulating lipocalin-2 (LCN2) expression in microglia, which subsequently induces expressions of chemokine CCL2 and pro-inflammatory cytokine. Subsequently, LPS-preconditioning lessened the resident microglia population (CD11b+CD45intCCL2+) in the brains of the RSDS-defeated mice. Moreover, RSDS-associated expressions of leukocytes (CD11b+CD45+CCR2+) and neutrophils (CD11b+CD45+Ly6G+) in the bone marrow, spleen, and blood were also attenuated by LPS-preconditioning. In particular, LPS preconditioning also promoted the expression of endogenous antioxidants and anti-inflammatory proteins in the hippocampus. Our results demonstrate that LPS preconditioning ameliorates lipocalin 2-associated microglial activation and aberrant immune response and promotes the expression of endogenous antioxidants and anti-inflammatory protein, thereby maintaining the homeostasis of pro-inflammation/anti-inflammation in both the brain and immune system, ultimately protecting the mice from RSDS-induced aberrant immune response and behavioral changes.

Synthesis and evaluation of 2-methylbenzothiazole derivatives as monoamine oxidase inhibitors

AbstractNeurodegenerative disorders are caused by the progressive death of neuronal cells in specific regions of the brain and spinal cord. The most common neurodegenerative disorders are Alzheimer’s disease and Parkinson’s disease. The inhibition of enzymes that metabolise neurotransmitter amines is an important approach in the treatment of these disorders and monoamine oxidase (MAO) B inhibitors have thus been used for the treatment of Parkinson’s disease. Inhibitors of the MAO-A isoform, in turn, are used clinically for the treatment of affective (e.g., major depression) and anxiety disorders. Recent studies have shown that benzothiazole derivatives act as potent MAO inhibitors. Based on these findings, the present study group synthesised thirteen 2-methylbenzo[d]thiazole derivatives and evaluated their in vitro MAO inhibition properties. The results showed that the benzothiazole derivatives were potent and selective inhibitors of human MAO-B, with all compounds exhibiting IC50 values < 0.017 µM. The most potent MAO-B inhibitor (4d) had an IC50 value of 0.0046 µM, while the most potent MAO-A inhibitor (5e) had an IC50 value of 0.132 µM. It may be concluded that active benzothiazole derivatives may serve as potential leads for the development of MAO inhibitors for the treatment of neuropsychiatric and neurodegenerative disorders.

Empagliflozin and dapagliflozin decreased atrial monoamine oxidase expression and alleviated oxidative stress in overweight non-diabetic cardiac patients.

The sodium-glucose-cotransporter 2 inhibitors (SGLT2i) are the blockbuster antidiabetic drugs that exert cardiovascular protection via pleiotropic effects. We have previously demonstrated that empagliflozin decreased monoamine oxidase (MAO) expression and oxidative stress in human mammary arteries. The present study performed in overweight, non-diabetic cardiac patients was aimed to assess whether the two widely prescribed SGLT2i decrease atrial MAO expression and alleviate oxidative stress elicited by exposure to angiotensin 2 (ANG2) and high glucose (GLUC). Right atrial appendages isolated during cardiac surgery were incubated ex vivo with either empagliflozin or dapagliflozin (1, 10µm, 12h) in the presence or absence of ANG2 (100nm) and GLUC (400mg/dL) and used for the evaluation of MAO-A and MAO-B expression and ROS production. Stimulation with ANG2 and GLUC increased atrial expression of both MAOs and oxidative stress; the effects were significantly decreased by the SGLT2i. Atrial oxidative stress positively correlated with the echocardiographic size of heart chambers and negatively with the left ventricular ejection fraction. In overweight patients, MAO contributes to cardiac oxidative stress in basal conditions and those that mimicked the renin-angiotensin system activation and hyperglycemia and can be targeted with empagliflozin and dapagliflozin, as novel off-target class effect of the SGLT2i.

Good parent-child relationship protects against alcohol use in maltreated adolescent females carrying the MAOA-uVNTR susceptibility allele.

Risk-allele carriers of a Monoamine oxidase A (MAOA) gene, short-allele (MAOA-S) in males and long-allele (MAOA-L) in females, in the presence of a negative environment, are associated with alcohol misuse. Whether MAOA-S/L alleles also present susceptibility to a positive environment to mitigate the risk of alcohol misuse is unknown. Thus, we assessed the association of the three-way interaction of MAOA, maltreatment, and positive parent-child relationship with alcohol consumption among adolescents. This prospective study included 1416 adolescents (females: 59.88%) aged 16 - 19 years from Sweden, enrolled in the "Survey of Adolescent Life in Västmanland" in 2012. Adolescents self-reported alcohol consumption, maltreatment by a family (FM) or non-family member (NFM), parent-child relationship, and left saliva for MAOA genotyping. We observed sex-dependent results. Females carrying MAOA-L with FM or NFM and a good parent-child relationship reported lower alcohol consumption than those with an average or poor parent-child relationship. In males, the interactions were not significant. Results suggest MAOA-L in females, conventionally regarded as a "risk", is a "plasticity" allele as it is differentially susceptible to negative and positive environments. Results highlight the importance of a good parent-child relationship in mitigating the risk of alcohol misuse in maltreated individuals carrying genetic risk. However, the interactions were not significant after adjusting to several environmental and behavioural covariates, especially parent's alcohol use, negative parent-child relationship, and nicotine use (smoking and/or snus), suggesting predictor and outcome intersection. Future studies and frameworks for preventive strategies should consider these covariates together with alcohol consumption. More studies with larger sample sizes are needed to replicate the findings.

The Impact of Antidepressants on Gut Microbiome and Depression Management

Depression is a widespread psychiatric disorder that significantly impacts an individual’s quality of life. It affects mental and emotional well-being and has far-reaching consequences on their physical health, relationships, and overall ability to function in daily life. Recent advances in psychiatric research have revealed a connection between the gut-brain axis, a bidirectional communication system linking the brain's emotional and cognitive centers with intestinal functions. Antidepressants, including selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOIs), are commonly prescribed to alleviate symptoms of depression. However, their influence extends beyond neurotransmitter modulation in the brain to significant effects on gastrointestinal physiology. Antidepressants can alter gut motility, secretion, and microbiota composition, which in turn can influence mood and mental health. This review aims to provide insights into the impact of antidepressants on gut health and their implications for depression treatment. Additionally, it explores the potential of probiotics as an adjunct treatment to enhance the efficacy of antidepressants and mitigate gastrointestinal side effects. Restoring healthy gut microbiota can improve gastrointestinal and mental health outcomes, suggesting a promising avenue for integrated therapeutic approaches.

Clinical Application of 18 F-THK5351 PET to Image Ongoing Astrogliosis in MSA-P and MSA-C.

18 F-labeled THK5351 PET can visualize ongoing astrogliosis by estimating monoamine oxidase B levels and can be used as an adjunct for diagnosing neurodegenerative disorders. Little has been reported on multiple system atrophy (MSA) in the differential diagnosis of parkinsonian syndromes. Here, we present 18 F-THK5351 images in typical cases of MSA-P (parkinsonian type) and MSA-C (cerebellar type), showing intense 18 F-THK5351 uptake in the lateral-posterior part of the putamen (MSA-P) and in the pons and middle cerebellar peduncles (MSA-C). Hence, this study illustrates the possible utility of 18 F-THK5351 PET as an adjunct for diagnosing MSA-P and MSA-C by imaging ongoing astrogliosis.

Stimulatory effect of eurycomanone from Eurycoma longifolia Jack roots on dopamine secretion in human neuroblastoma SH-SY5Y cell line

Eurycomanone has been identified as the major bioactive compound contributing to Eurycoma longifolia (EL) aphrodisiac activity, however, its mechanism of action remains obscured. Presently, eurycomanone was isolated from EL root extract and its molecular structure was identified. The human neuroblastoma SH-SY5Y cell line was differentiated into human dopaminergic neuron-like cells. Exogenous dopamine levels from the differentiated SH-SY5Y cells were quantified following the treatment of 5, 10, 15 μM of eurycomanone and 10 μM clorgyline as positive control. Dopamine secretion was significantly increased in a dose-dependent manner, compared to the vehicle control (p < .01) in differentiated SH-SY5Y cells. Dopamine concentration stimulated by 15 μM eurycomanone was significantly higher than clorgyline (p < .05), an inhibitor of monoamine oxidase A that suppresses dopamine catabolism. In conclusion, eurycomanone stimulated dopamine release of human SH-SY5Y neuron-like cells, which could be one of the mechanisms that underpin the aphrodisiac properties of the plant.

Preliminary study on cytotoxicity of selegiline on different cancer cell lines: exploration of the induction of ROS-independent apoptosis in breast cancer cells.

The concept of drug repurposing is now widely utilized by biomedical scientists for drug discovery. An example of this is the use of selegiline (SEL), a monoamine oxidase inhibitor that was initially used for the management of depression but is now being considered for another purpose. This study compares the cytotoxic effects of SEL on different cancer cells. Further, the study explores the molecular mechanism of cell death, validating the possibility of its repurposing for cancer. Preliminary analysis of network pharmacological data was conducted in silico, followed by in vitro cytotoxicity tests on PC12, G361, MDA-MB231, MCF7, THP-1, and Hela cells under normoxic and hypoxic conditions, using the MTT assay. The mechanism of cell death was then confirmed by performing DAPI and FITC-conjugated Annexin V and Propidium Iodide (PI) staining assays. Additionally, ROS levels and PKC phosphorylation were also evaluated. In silico analysis has revealed that SEL is associated with ten genes linked to different cancer types. Specifically, SEL was most cytotoxic to neuronal pheochromocytoma, triple-negative human epithelial breast cancer cells, and ER+ and PR+ breast cancer cells. Furthermore, it was observed that this cell death occurred through ROS-independent apoptosis pathways. In addition, SEL was found to inhibit the phosphorylation of PKC, which may contribute to cell death. SEL induces apoptosis in breast cancer cells independently of reactive oxygen species and inhibits the phosphorylation of protein kinase C, which merits further exploration.

Identification of Sarmentosin as a Key Bioactive from Blackcurrants (Ribes nigrum) for Inhibiting Platelet Monoamine Oxidase in Humans.

Previous clinical studies indicate that monoamine oxidase-B (MAO-B) inhibition by blackcurrants must be predominantly attributed to bioactives other than anthocyanins. In this natural products discovery study, MAO-A/B inhibitory phytochemicals were isolated from blackcurrants, and a double-blind crossover study investigated the efficacy of freeze-dried whole-fruit blackcurrant powder in inhibiting MAO-B compared with blackcurrant juice in healthy adults. Platelet MAO-B inhibition was comparable between powder (89% ± 6) and juice (91% ± 4), and it was positively correlated with MAO-modulated plasma catecholamines, subjective alertness, and reduced mental fatigue, assessed using the Bond-Lader questionnaire. Sarmentosin, a nitrile glycoside, and its hydroxycinnamoyl esters were identified as novel MAO-A/B inhibitors from blackcurrant in vitro, and sarmentosin was demonstrated to inhibit platelet MAO-B activity in vivo. These findings confirm sarmentosin as the primary bioactive for MAO-A/B inhibition in blackcurrants, as well as its bioavailability and stability during freeze-drying, and suggest that consuming blackcurrant powder and juice may positively affect mood in healthy adults.

Rasagiline Exerts Neuroprotection towards Oxygen-Glucose-Deprivation/Reoxygenation-Induced GAPDH-Mediated Cell Death by Activating Akt/Nrf2 Signaling.

Rasagiline (Azilect®) is a selective monoamine oxidase B (MAO-B) inhibitor that provides symptomatic benefits in Parkinson's disease (PD) treatment and has been found to exert preclinical neuroprotective effects. Here, we investigated the neuroprotective signaling pathways of acute rasagiline treatment for 22 h in PC12 neuronal cultures exposed to oxygen-glucose deprivation (OGD) for 4 h, followed by 18 h of reoxygenation (R), causing 40% aponecrotic cell death. In this study, 3-10 µM rasagiline induced dose-dependent neuroprotection of 20-80%, reduced the production of the neurotoxic reactive oxygen species by 15%, and reduced the nuclear translocation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by 75-90%. In addition, 10 µM rasagiline increased protein kinase B (Akt) phosphorylation by 50% and decreased the protein expression of the ischemia-induced α-synuclein protein by 50% in correlation with the neuroprotective effect. Treatment with 1-5 µM rasagiline induced nuclear shuttling of transcription factor Nrf2 by 40-90% and increased the mRNA levels of the antioxidant enzymes heme oxygenase-1, (NAD (P) H- quinone dehydrogenase, and catalase by 1.8-2.0-fold compared to OGD/R insult. These results indicate that rasagiline provides neuroprotection to the ischemic neuronal cultures through the inhibition of α-synuclein and GAPDH-mediated aponecrotic cell death, as well as via mitochondrial protection, by increasing mitochondria-specific antioxidant enzymes through a mechanism involving the Akt/Nrf2 redox-signaling pathway. These findings may be exploited for neuroprotective drug development in PD and stroke therapy.

Concomitant Administration of Ozanimod and Serotonergic Antidepressants in Patients With Ulcerative Colitis or Relapsing Multiple Sclerosis.

Ozanimod, approved for the treatment of moderately to severely active ulcerative colitis (UC) and relapsing multiple sclerosis (RMS), is a weak in vitro monoamine oxidase B (MAO-B) inhibitor. MAO-B inhibitors can cause serotonin accumulation with concomitant use of selective serotonin reuptake inhibitors (SSRIs) or serotonin and norepinephrine reuptake inhibitors (SNRIs). We evaluated the incidence of treatment-emergent adverse events (TEAEs) potentially associated with serotonin accumulation during ozanimod and concomitant SSRI/SNRI use in this post hoc analysis of pooled UC studies and the open-label extension RMS DAYBREAK. Data for ozanimod 0.92mg from pooled UC studies (n = 1158; cutoff: January 10, 2022) and RMS DAYBREAK (n = 2257; cutoff: February 1, 2022) were analyzed. Concomitant SSRI/SNRI use was allowed in the UC (n = 67) and RMS (n = 274) studies. A narrow Medical Dictionary for Regulatory Activities search ("serotonin syndrome," "neuroleptic malignant syndrome," and "malignant hyperthermia") and a broad search including terms potentially associated with serotonin accumulation were conducted. The percentages of patients with TEAEs in both searches were analyzed by concomitant SSRI/SNRI use when the TEAE occurred. No patients had TEAEs matching the narrow search criteria. No differences were observed in the percentages of patients with ≥1 TEAE matching the broad search regardless of SSRI/SNRI use in UC (with: 25.4% [n = 17 of 67]; without: 15.0% [n = 164 of 1091]) and RMS (with: 12.4% [n = 34 of 274]; without: 15.6% [n = 310 of 1982]) studies. No evidence of increased TEAEs potentially associated with serotonin accumulation was observed with concurrent use of ozanimod and SSRIs/SNRIs. NCT01647516, NCT02531126, NCT02435992, NCT02576717.

Synthesis, biochemistry, and in silico investigations of isatin-based hydrazone derivatives as monoamine oxidase inhibitors

Ten isatin-based hydrazone derivatives were synthesized using two subseries, IA (isatin + acetophenone) and IB (isatin + benzaldehyde), and evaluated for their monoamine oxidases (MAOs) inhibitory activity. All the compounds showed stronger MAO-A inhibition than MAO-B, and the IB series showed more effective MAO-A inhibitory activity than IA series. Compound IB4 most potently inhibited MAO-A (half maximal inhibitory concentration IC50 = 0.015 µM), followed by IB3 (IC50 = 0.019 µM). On the contrary, compound IB3 showed the highest MAO-B inhibition (IC50 = 0.068 µM), followed by IB4 (IC50 = 1.87 µM). Compound IB3 and IB4 had low selectivity indices of 3.68 and 8.50, respectively. Structurally, the methyl group of IA series decreased the inhibition of both MAO-A and MAO-B. Among them, IB3 and IB4 (4-Cl and 4-Br in B-ring, respectively) showed higher MAO-A and MAO-B inhibition than the other substitutions. Inhibition constant Ki values of IB3 and IB4 for MAO-A were 0.0088 and 0.0063 µM, respectively, and those for MAO-B were 0.048 and 0.060 µM, respectively. IB3 and IB4 were competitive, reversible inhibitors of MAO-A and MAO-B. Molecular docking analysis predicted that IB3 and IB4 formed stable hydrogen bonds between Asn181 and the NH atom of isatin in the ligand-protein complex. Dynamic analysis revealed that IB3 and IB4 are stable with both MAO isoforms. These observations suggest IB3 and IB4 are potent and reversible MAO-A and MAO-B inhibitors and both compounds can be used as therapeutic agents for neurological disorders.

A Comprehensive Review of The Molecular Dynamic Study Of Chalcones, Coumarins and Chromones as Selective MAO‐B Inhibitors [2015‐Till Date

AbstractMolecular dynamics (MD) simulation is an in silico method used in the biomolecular level of research to study how the protein interacts with the target with time. It provides a detailed information of the protein dynamics and ligand structure with the crucial amino acid interactions. Monoamine oxidase B (MAO−B) is a crucial isoenzyme responsible for the catalyses of oxidative deamination of various biogenic amines in the brain and peripheral tissues. The selective inhibitors of MAO−B are considered as the management of symptoms of neurodegenerative disorders like Alzheimer's disease(AD) and Parkinson disease(PD). Recently the structural scaffolds containing chalcones, coumarins and chromones derived candidates shown potent, selective, competitive and reversible type of MAO−B inhibitors. The structural similarities between the above scaffolds can produce almost similar type of interactions in the inhibitor binding cavity of MAO−B. Numerous molecular simulation reports were supported by the above mentioned fact. The current review focus on the last ten year molecular dynamics report of chalcones, coumarins and chromones towards MAO−B inhibition. The review also focuses on the software details used in the MD dynamics simulation and the structural requirement from each class of compound for the recognition of MAO−B inhibitory activity.

Mechanisms involved in the antidepressant-like action of orally administered 5-((4-methoxyphenyl)thio)benzo[c][1,2,5]thiadiazole (MTDZ) in male and female mice.

The compound 5-((4-methoxyphenyl)thio)benzo[c][1,2,5]thiadiazole (MTDZ) has recently been shown to inhibit in vitro acetylcholinesterase activity, reduce cognitive damage, and improve neuropsychic behavior in mice, making it a promising molecule to treat depression. This study investigated the antidepressant-like action of MTDZ in mice and its potential mechanisms of action. Molecular docking assays were performed and suggested a potential inhibition of monoamine oxidase A (MAO-A) by MTDZ. The toxicity study revealed that MTDZ displayed no signs of toxicity, changes in oxidative parameters, or alterations to biochemistry markers, even at a high dose of 300 mg/kg. In behavioral tests, MTDZ administration reduced immobility behavior during the forced swim test (FST) without adjusting the climbing parameter, suggesting it has an antidepressant effect. The antidepressant-like action of MTDZ was negated with the administration of 5-HT1A, 5-HT1A/1B, and 5-HT3 receptor antagonists, implying the involvement of serotonergic pathways. Moreover, the antidepressant-like action of MTDZ was linked to the NO system, as L-arginine pretreatment inhibited its activity. The ex vivo assays indicated that MTDZ normalized ATPase activity, potentially linking this behavior to its antidepressant-like action. MTDZ treatment restricted MAO-A activity in the cerebral cortices and hippocampi of mice, proposing a selective inhibition of MAO-A associated with the antidepressant-like effect of the compound. These findings suggest that MTDZ may serve as a promising antidepressant agent due to its selective inhibition of MAO-A and the involvement of serotonergic and NO pathways.

Levodopa versus levodopa sparing in early parkinson's disease: can we meet halfway?

Monotherapy is the recommended initial treatment for early Parkinson's disease. The pharmacological options for initial treatment include dopaminergic agonists, monoamine oxidase B inhibitors, and levodopa formulations. Several factors should be considered when selecting the optimal treatment, such as disease severity, disease duration, age, activity level, and the risk of developing motor and non-motor complications. Early evidence on the potential role of levodopa formulations in the risk of dyskinesia led to levodopa aversion in the late 1990s and early 2000s, favoring the use of levodopa-sparing options like dopamine agonists. This shift resulted in an increase in behavioral adverse effects, such as impulse control disorders, leading to a subsequent dopamine agonist aversion in the mid-2000s. This review aims to provide a comprehensive evaluation of the existing literature regarding the benefits and drawbacks of levodopa versus levodopa-sparing strategies in drug-naive early-stage Parkinson's disease.