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European Journal of Pharmacology Aug 2024Dopaminergic neurons express a heteromer composed of the dopamine D3 receptor and the α4β2 nicotinic acetylcholine receptor, the D3R-nAChR heteromer, activated by both...
Dopaminergic neurons express a heteromer composed of the dopamine D3 receptor and the α4β2 nicotinic acetylcholine receptor, the D3R-nAChR heteromer, activated by both nicotine and dopamine D2 and D3 receptors agonists, such as quinpirole, and crucial for dopaminergic neuron homeostasis. We now report that D3R-nAChR heteromer activity is potentiated by 17-β-estradiol which acts as a positive allosteric modulator by binding a specific domain on the α4 subunit of the nicotinic receptor protomer. In mouse dopaminergic neurons, in fact, 17-β-estradiol significantly increased the ability of nicotine and quinpirole in promoting neuron dendritic remodeling and in protecting neurons against the accumulation of α-synuclein induced by deprivation of glucose, with a mechanism that does not involve the classical estrogen receptors. The potentiation induced by 17-β-estradiol required the D3R-nAChR heteromer since either nicotinic receptor or dopamine D3 receptor antagonists and interfering TAT-peptides, but not the estrogen receptor antagonist fulvestrant, specifically prevented 17-β-estradiol effects. Evidence of estrogens neuroprotection, mainly mediated by genomic mechanisms, have been provided, which is in line with epidemiological data reporting that females are less likely to develop Parkinson's Disease than males. Therefore, potentiation of D3R-nAChR heteromer activity may represent a further mechanism by which 17-β-estradiol reduces dopaminergic neuron vulnerability.
Topics: Receptors, Dopamine D3; Estradiol; Animals; Dopaminergic Neurons; Receptors, Nicotinic; Mice; Neuroprotective Agents; Female; Male
PubMed: 38821163
DOI: 10.1016/j.ejphar.2024.176678 -
Frontiers in Bioscience (Landmark... May 2024Colorectal cancer (CRC) is a major cause of mortality and morbidity. A study proved that brexpiprazole, as a novel dopamine receptor partial agonist, can also prevent...
BACKGROUND
Colorectal cancer (CRC) is a major cause of mortality and morbidity. A study proved that brexpiprazole, as a novel dopamine receptor partial agonist, can also prevent CRC cell proliferation. Therefore, clarifying the molecular mechanism of brexpiprazole is vital to developing a novel therapeutic strategy for CRC.
METHODS
The effect of brexpiprazole on human colorectal cancer cell proliferation was measured with Cell Counting Kit-8 (CCK-8) kits. Cell migration capability was measured using wound healing and transwell. Cell apoptosis was evaluated with a flow cytometer. Western blots and immunohistochemical staining were used to evaluate protein expression. The effects observed were also confirmed in xenograft models.
RESULTS
Brexpiprazole remarkably inhibited the proliferation, suppressed the migration ability, and induced apoptosis of colorectal cancer cells. Mechanism study showed that brexpiprazole exerted these effects by inhibiting the EGFR pathway. Brexpiprazole enhanced HCT116 cells' sensitivity to cetuximab, and a combination of brexpiprazole and cetuximab inhibited xenograft tumor growth .
CONCLUSIONS
Our finding suggested that brexpiprazole inhibits proliferation, promotes apoptosis, and enhances CRC cells' sensitivity to cetuximab by regulating the EGFR pathway and it might be an efficacious treatment strategy for CRC.
Topics: Humans; Colorectal Neoplasms; Thiophenes; ErbB Receptors; Animals; Cell Proliferation; Apoptosis; Cetuximab; Mice, Nude; Xenograft Model Antitumor Assays; Quinolones; Cell Movement; Cell Line, Tumor; Mice; HCT116 Cells; Mice, Inbred BALB C; Disease Progression
PubMed: 38812296
DOI: 10.31083/j.fbl2905174 -
Scientific Reports May 2024Dysfunction of subcortical D2-like dopamine receptors (DRs) can lead to positive symptoms of schizophrenia, and their analog, the increased locomotor activity in...
Dysfunction of subcortical D2-like dopamine receptors (DRs) can lead to positive symptoms of schizophrenia, and their analog, the increased locomotor activity in schizophrenia model MAM-E17 rats. The ventral pallidum (VP) is a limbic structure containing DRs. The DR antagonist sulpiride is a widespread antipsychotic drug, which can alleviate positive symptoms in human patients. However, it is still not known how sulpiride can influence positive symptoms via VP DRs. We hypothesize that the microinjection of sulpiride into the VP can normalize hyperactivity in MAM-E17 rats. In addition, recently, we showed that the microinjection of sulpirid into the VP induces place preference in neurotypical rats. Thus, we aimed to test whether intra-VP sulpiride can also have a rewarding effect in MAM-E17 rats. Therefore, open field-based conditioned place preference (CPP) test was applied in neurotypical (SAL-E17) and MAM-E17 schizophrenia model rats to test locomotor activity and the potential locomotor-reducing and rewarding effects of sulpiride. Sulpiride was microinjected bilaterally in three different doses into the VP, and the controls received only vehicle. The results of the present study demonstrated that the increased locomotor activity of the MAM-E17 rats was caused by habituation disturbance. Accordingly, larger doses of sulpiride in the VP reduce the positive symptom-analog habituation disturbance of the MAM-E17 animals. Furthermore, we showed that the largest dose of sulpiride administered into the VP induced CPP in the SAL-E17 animals but not in the MAM-E17 animals. These findings revealed that VP DRs play an important role in the formation of positive symptom-like habituation disturbances in MAM-E17 rats.
Topics: Animals; Sulpiride; Schizophrenia; Antipsychotic Agents; Rats; Basal Forebrain; Disease Models, Animal; Male; Microinjections; Habituation, Psychophysiologic; Locomotion; Receptors, Dopamine D2
PubMed: 38811614
DOI: 10.1038/s41598-024-63059-y -
Neuropharmacology Sep 2024Diets high in sucrose and fat are becoming more prevalent the world over, accompanied by a raised prevalence of cardiovascular diseases, cancers, diabetes, obesity, and...
Diets high in sucrose and fat are becoming more prevalent the world over, accompanied by a raised prevalence of cardiovascular diseases, cancers, diabetes, obesity, and metabolic syndrome. Clinical studies link unhealthy diets with the development of mental health disorders, particularly depression. Here, we investigate the effects of 12 days of sucrose consumption administered as 2 L of 25% sucrose solution daily for 12 days in Göttingen minipigs on the function of brain receptors involved in reward and motivation, regulating feeding, and pre- and post-synaptic mechanisms. Through quantitative autoradiography of cryostat sections containing limbic brain regions, we investigated the effects of sucrose restricted to a 1-h period each morning, on the specific binding of [H]raclopride on dopamine D2/3 receptors, [H]UCB-J at synaptic vesicle glycoprotein 2A (SV2A), [H]MPEPγ at metabotropic glutamate receptor subtype 5 (mGluR5) and [H]SR141716A at the cannabinoid receptor 1 (CB1). Compared to control diet animals, the sucrose group showed significantly lower [H]UCB-J and [H]MPEPγ binding in the prefrontal cortex. The sucrose-consuming minipigs showed higher hippocampal CB1 binding, but unaltered dopamine D2/3 binding compared to the control group. We found that the sucrose diet reduced the synaptic density marker while increasing CB1 binding in limbic brain structures, which may subserve maladaptive changes in appetite regulation and feeding. Further studies of the effects of diets and lifestyle habits on brain neuroreceptor and synaptic density markers are warranted.
Topics: Animals; Swine, Miniature; Swine; Sucrose; Male; Receptor, Metabotropic Glutamate 5; Receptors, Cannabinoid; Synapses; Receptor, Cannabinoid, CB1; Receptors, Dopamine D2; Brain; Female; Receptors, Dopamine D3
PubMed: 38810925
DOI: 10.1016/j.neuropharm.2024.110018 -
Journal of Neuroinflammation May 2024Intrauterine inflammation is considered a major cause of brain injury in preterm infants, leading to long-term neurodevelopmental deficits. A potential contributor to...
BACKGROUND
Intrauterine inflammation is considered a major cause of brain injury in preterm infants, leading to long-term neurodevelopmental deficits. A potential contributor to this brain injury is dysregulation of neurovascular coupling. We have shown that intrauterine inflammation induced by intra-amniotic lipopolysaccharide (LPS) in preterm lambs, and postnatal dopamine administration, disrupts neurovascular coupling and the functional cerebral haemodynamic responses, potentially leading to impaired brain development. In this study, we aimed to characterise the structural changes of the neurovascular unit following intrauterine LPS exposure and postnatal dopamine administration in the brain of preterm lambs using cellular and molecular analyses.
METHODS
At 119-120 days of gestation (term = 147 days), LPS was administered into the amniotic sac in pregnant ewes. At 126-7 days of gestation, the LPS-exposed lambs were delivered, ventilated and given either a continuous intravenous infusion of dopamine at 10 µg/kg/min or isovolumetric vehicle solution for 90 min (LPS, n = 6; LPS, n = 6). Control preterm lambs not exposed to LPS were also administered vehicle or dopamine (CTL, n = 9; CTL, n = 7). Post-mortem brain tissue was collected 3-4 h after birth for immunohistochemistry and RT-qPCR analysis of components of the neurovascular unit.
RESULTS
LPS exposure increased vascular leakage in the presence of increased vascular density and remodelling with increased astrocyte "end feet" vessel coverage, together with downregulated mRNA levels of the tight junction proteins Claudin-1 and Occludin. Dopamine administration decreased vessel density and size, decreased endothelial glucose transporter, reduced neuronal dendritic coverage, increased cell proliferation within vessel walls, and increased pericyte vascular coverage particularly within the cortical and deep grey matter. Dopamine also downregulated VEGFA and Occludin tight junction mRNA, and upregulated dopamine receptor DRD1 and oxidative protein (NOX1, SOD3) mRNA levels. Dopamine administration following LPS exposure did not exacerbate any effects induced by LPS.
CONCLUSION
LPS exposure and dopamine administration independently alters the neurovascular unit in the preterm brain. Alterations to the neurovascular unit may predispose the developing brain to further injury.
Topics: Animals; Dopamine; Sheep; Female; Animals, Newborn; Lipopolysaccharides; Pregnancy; Brain; Inflammation; Blood-Brain Barrier; Premature Birth
PubMed: 38807204
DOI: 10.1186/s12974-024-03137-0 -
ENeuro Jun 2024Amylin, a pancreatic hormone that is cosecreted with insulin, has been highlighted as a potential treatment target for obesity. Amylin receptors are distributed widely...
Amylin, a pancreatic hormone that is cosecreted with insulin, has been highlighted as a potential treatment target for obesity. Amylin receptors are distributed widely throughout the brain and are coexpressed on mesolimbic dopamine neurons. Activation of amylin receptors is known to reduce food intake, but the neurochemical mechanisms behind this remain to be elucidated. Amylin receptor activation in the ventral tegmental area (VTA), a key dopaminergic nucleus in the mesolimbic reward system, has a potent ability to suppress intake of palatable fat and sugar solutions. Although previous work has demonstrated that VTA amylin receptor activation can dampen mesolimbic dopamine signaling elicited by random delivery of sucrose, whether this is also the case for fat remains unknown. Herein we tested the hypothesis that amylin receptor activation in the VTA of male rats would attenuate dopamine signaling in the nucleus accumbens core in response to random intraoral delivery of either fat or sugar solutions. Results show that fat solution produces a greater potentiation of accumbens dopamine than an isocaloric sucrose solution. Moreover, activation of VTA amylin receptors elicits a more robust suppression of accumbens dopamine signaling in response to fat solution than to sucrose. Taken together these results shed new light on the amylin system as a therapeutic target for obesity and emphasize the reinforcing nature of high-fat/high-sugar diets.
Topics: Animals; Ventral Tegmental Area; Male; Dopamine; Nucleus Accumbens; Receptors, Islet Amyloid Polypeptide; Rats, Sprague-Dawley; Dietary Fats; Signal Transduction; Amylin Receptor Agonists; Rats; Sucrose
PubMed: 38806231
DOI: 10.1523/ENEURO.0133-24.2024 -
Journal of Affective Disorders Aug 2024Major depressive disorder (MDD) is considerably heterogeneous in terms of comorbidities, which may hamper the disentanglement of its biological mechanism. In a previous...
BACKGROUND
Major depressive disorder (MDD) is considerably heterogeneous in terms of comorbidities, which may hamper the disentanglement of its biological mechanism. In a previous study, we classified the lifetime trajectories of MDD-related multimorbidities into seven distinct clusters, each characterized by unique genetic and environmental risk-factor profiles. The current objective was to investigate genome-wide gene-by-environment (G × E) interactions with childhood trauma burden, within the context of these clusters.
METHODS
We analyzed 77,519 participants and 6,266,189 single-nucleotide polymorphisms (SNPs) of the UK Biobank database. Childhood trauma burden was assessed using the Childhood Trauma Screener (CTS). For each cluster, Plink 2.0 was used to calculate SNP × CTS interaction effects on the participants' cluster membership probabilities. We especially focused on the effects of 31 candidate genes and associated SNPs selected from previous G × E studies for childhood maltreatment's association with depression.
RESULTS
At SNP-level, only the high-multimorbidity Cluster 6 revealed a genome-wide significant SNP rs145772219. At gene-level, MPST and PRH2 were genome-wide significant for the low-multimorbidity Clusters 1 and 3, respectively. Regarding candidate SNPs for G × E interactions, individual SNP results could be replicated for specific clusters. The candidate genes CREB1, DBH, and MTHFR (Cluster 5) as well as TPH1 (Cluster 6) survived multiple testing correction.
LIMITATIONS
CTS is a short retrospective self-reported measurement. Clusters could be influenced by genetics of individual disorders.
CONCLUSIONS
The first G × E GWAS for MDD-related multimorbidity trajectories successfully replicated findings from previous G × E studies related to depression, and revealed risk clusters for the contribution of childhood trauma.
Topics: Humans; Depressive Disorder, Major; Polymorphism, Single Nucleotide; Female; Male; Multimorbidity; Middle Aged; Gene-Environment Interaction; Adult; Genome-Wide Association Study; Aged; United Kingdom; Risk Factors; Genetic Predisposition to Disease; Adverse Childhood Experiences
PubMed: 38806065
DOI: 10.1016/j.jad.2024.05.126 -
Journal of Medicinal Chemistry Jun 2024Development of more efficacious medications with improved safety profiles to manage and treat multiple forms of pain is a critical element of healthcare. To this end, we...
Development of more efficacious medications with improved safety profiles to manage and treat multiple forms of pain is a critical element of healthcare. To this end, we have designed and synthesized a novel class of tetracyclic pyridopyrroloquinoxalinone derivatives with analgesic properties. The receptor binding profiles and analgesic properties of these tetracyclic compounds were studied. Systematic optimizations of this novel scaffold culminated in the discovery of the clinical candidate, (6,10)-8-[3-(4-fluorophenoxy)propyl]-6,7,8,9,10,10-hexahydro-1-pyrido[3',4':4,5]pyrrolo[1,2,3-]quinoxalin-2(3)-one (compound , ITI-333), which exhibited potent binding affinity to serotonin 5-HT ( = 8.3 nM) and μ-opioid receptors (MOR, = 11 nM) and moderate affinity to adrenergic α ( = 28 nM) and dopamine D ( = 50 nM) receptors. ITI-333 acts as a 5-HT receptor antagonist, a MOR partial agonist, and an adrenergic α receptor antagonist. ITI-333 exhibited dose-dependent analgesic effects in rodent models of acute pain. Currently, this investigational new drug is in phase I clinical development.
Topics: Animals; Humans; Analgesics; Structure-Activity Relationship; Administration, Oral; Pain; Mice; Male; Rats; Drug Discovery; Rats, Sprague-Dawley; Biological Availability; Receptors, Opioid, mu; Pyridines; Pyrroles
PubMed: 38805667
DOI: 10.1021/acs.jmedchem.4c00480 -
Pain Physician May 2024Flupentixol and melitracen are being investigated for their potential effectiveness in managing persistent idiopathic facial pain (PIFP), based on their mechanisms of... (Observational Study)
Observational Study
BACKGROUND
Flupentixol and melitracen are being investigated for their potential effectiveness in managing persistent idiopathic facial pain (PIFP), based on their mechanisms of action as dopamine receptor antagonists and noradrenaline/serotonin reuptake inhibitors, respectively. The efficacy and safety of flupentixol and melitracen (FM) tablets in treating PIFP were retrospectively analyzed at our hospital.
OBJECTIVES
The aim of this study is to determine the effectiveness and safety of FM tablets in treating PIFP.
STUDY DESIGN
Retrospective unicentric cohort design.
SETTING
An academic university hospital.
METHODS
A retrospective analysis was conducted on a cohort comprising 128 patients with a definite diagnoses of PIFP who were treated with FM tablets (flupentixol 0.5 mg and melitracen 10 mg tablet, >= 4 tablets/d) from January 2022 through May 2023 at an academic university hospital. Baseline conditions were statistically described, and Numeric Rating Scale (NRS-11) scores of pain levels before and during treatment were collected. Pain relief rates were calculated. Differences in baseline characteristics between responsive and unresponsive patients were evaluated using statistical tests. Additionally, the side effects experienced during treatment were summarized.
RESULTS
Among the included 128 patients, 105 (82.0%) patients achieved pain relief (pain NRS-11 score reduction rate >= 50%). The median treatment onset time was 3 (1-7) days. NRS-11 scores of responsive patients at week 2, week 4, week 8, and week 12 were significantly lower than the baseline NRS-11 scores (P < 0.001), regardless of their Hamilton Depression Rating Scale score. Pain duration was the only factor that related to responsiveness (Wilcoxon rank sum test, P < 0.001; logistic regression, P = 0.001). No serious side effects that could affect patients' lives were observed during the first week of treatments.
LIMITATIONS
Due to its retrospective nature, this study is limited by its lack of a randomized control. The lack of data on nonresponders who did not achieve significant pain relief hinders assessing overall change and the placebo effects'. Patients previously treated with antidepressants were excluded, making it hard to determine if FM tablets were a better treatment for PIFP. Additionally, the small sample size in a single center may be influenced by chance variation in pain relief.
CONCLUSIONS
FM tablets showed its potential in the management of PIFP with considerable efficacy and safety. Early administration of FM tablets after a PIFP diagnosis may result in a high possibility of pain relief.
Topics: Humans; Retrospective Studies; Male; Female; Middle Aged; Facial Pain; Adult; Flupenthixol; Tablets; Aged; Treatment Outcome
PubMed: 38805533
DOI: No ID Found -
Cell Reports May 2024Affective empathy enables social mammals to learn and transfer emotion to conspecifics, but an understanding of the neural circuitry and genetics underlying affective...
Affective empathy enables social mammals to learn and transfer emotion to conspecifics, but an understanding of the neural circuitry and genetics underlying affective empathy is still very limited. Here, using the naive observational fear between cagemates as a paradigm similar to human affective empathy and chemo/optogenetic neuroactivity manipulation in mouse brain, we investigate the roles of multiple brain regions in mouse affective empathy. Remarkably, two neural circuits originating from the ventral hippocampus, previously unknown to function in empathy, are revealed to regulate naive observational fear. One is from ventral hippocampal pyramidal neurons to lateral septum GABAergic neurons, and the other is from ventral hippocampus pyramidal neurons to nucleus accumbens dopamine-receptor-expressing neurons. Furthermore, we identify the naive observational-fear-encoding neurons in the ventral hippocampus. Our findings highlight the potentially diverse regulatory pathways of empathy in social animals, shedding light on the mechanisms underlying empathy circuity and its disorders.
PubMed: 38805397
DOI: 10.1016/j.celrep.2024.114277