Compulsive behaviors are observed in a range of psychiatric disorders, however the neural substrates underlying the behaviors are not clearly defined. Here we show that the basolateral amygdala-dorsomedial striatum (BLA-DMS) circuit activation leads to the manifestation of compulsive-like behaviors. We revealed that the BLA neurons projecting to the DMS, mainly onto dopamine D1 receptor-expressing neurons, largely overlap with the neuronal population that responds to aversive predator stress, a widely used anxiogenic stressor.
View Article and Find Full Text PDFDopamine neurons are essential for voluntary movement, reward learning, and motivation, and their dysfunction is closely linked to various psychological and neurodegenerative diseases. Hence, understanding the detailed signaling mechanisms that functionally modulate dopamine neurons is crucial for the development of better therapeutic strategies against dopamine-related disorders. Phospholipase Cγ1 (PLCγ1) is a key enzyme in intracellular signaling that regulates diverse neuronal functions in the brain.
View Article and Find Full Text PDFDopamine synapses play a crucial role in volitional movement and reward-related behaviors, while dysfunction of dopamine synapses causes various psychiatric and neurological disorders. Despite this significance, the true biological nature of dopamine synapses remains poorly understood. Here, we show that dopamine transmission is strongly correlated with GABA co-transmission across the brain and dopamine synapses are structured and function like GABAergic synapses with marked regional heterogeneity.
View Article and Find Full Text PDFWhen animals are faced with food depletion, food search-associated locomotion is crucial for their survival. Although food search-associated locomotion is known to be regulated by dopamine, it has yet to investigate the potential molecular mechanisms governing the regulation of genes involved in dopamine metabolism (e.g.
View Article and Find Full Text PDFThere is increasing evidence demonstrating that reward-related motivational food intake is closely connected with the brain's homeostatic system of energy balance and that this interaction might be important in the integrative control of feeding behavior. Dopamine regulates motivational behavior, including feeding behaviors, and the dopamine reward system is recognized as the most prominent system that controls appetite and motivational and emotional drives for food. It appears that the dopamine system exerts a critical role in the control of feeding behavior not only by the reward-related circuit, but also by contributing to the homeostatic circuit of food intake, suggesting that dopamine plays an integrative role across the converging circuitry of control of food intake by linking energy state-associated signals to reward-related behaviors.
View Article and Find Full Text PDFDopamine regulates reward-related behavior through the mesolimbic dopaminergic pathway. Stress affects dopamine levels and dopaminergic neuronal activity in the mesolimbic dopamine system. Changes in mesolimbic dopaminergic neurotransmission are important for coping with stress, as they allow adaption to behavioral responses to various environmental stimuli.
View Article and Find Full Text PDFWe previously reported that human carboxylesterase 1 (CES1), a serine esterase containing a unique -linked glycosyl group at Asn79 (N79 CES1), is a candidate serological marker of hepatocellular carcinoma (HCC). CES1 is normally present at low-to-undetectable levels in normal human plasma, HCC tumors, and major liver cancer cell lines. To investigate the potential mechanism underlying the suppression of CES1 expression in liver cancer cells, we took advantage of the low detectability of this marker in tumors by overexpressing in multiple HCC cell lines, including stable Hep3B cells.
View Article and Find Full Text PDFThe basal ganglia network has been implicated in the control of adaptive behavior, possibly by integrating motor learning and motivational processes. Both positive and negative reinforcement appear to shape our behavioral adaptation by modulating the function of the basal ganglia. Here, we examined a transgenic mouse line (G2CT) in which synaptic transmissions onto the medium spiny neurons (MSNs) of the basal ganglia are depressed.
View Article and Find Full Text PDFSMURF2 is a member of the HECT family of E3 ubiquitin ligases that have important roles as a negative regulator of transforming growth factor-β (TGF-β) signaling through ubiquitin-mediated degradation of TGF-β receptor I. However, the regulatory mechanism of SMURF2 is largely unknown. In this study, we identified that micro(mi)R-195 and miR-497 putatively target SMURF2 using several target prediction databases.
View Article and Find Full Text PDFDuring neural development, growing neuronal cells consistently sense and communicate with their surroundings through the use of signaling molecules. In this process, spatiotemporally well-coordinated intracellular signaling is a prerequisite for proper neuronal network formation. Thus, intense interest has focused on investigating the signaling mechanisms in neuronal structure formation that link the activation of receptors to the control of cell shape and motility.
View Article and Find Full Text PDFEpigenetic remodeling via histone acetylation has become a popular therapeutic strategy to treat Alzheimer's disease (AD). In particular, histone deacetylase (HDAC) inhibitors including M344 and SAHA have been elucidated to be new drug candidates for AD, improving cognitive abilities impaired in AD mouse models. Although emerged as a promising target for AD, most of the HDAC inhibitors are poorly selective and could cause unwanted side effects.
View Article and Find Full Text PDFImpulsivity is closely associated with addictive disorders, and changes in the brain dopamine system have been proposed to affect impulse control in reward-related behaviors. However, the central neural pathways through which the dopamine system controls impulsive behavior are still unclear. We found that the absence of the D2 dopamine receptor (D2R) increased impulsive behavior in mice, whereas restoration of D2R expression specifically in the central amygdala (CeA) of D2R knockout mice ( normalized their enhanced impulsivity.
View Article and Find Full Text PDFThe melanocortin-4 receptor (MC4R) belongs to the G protein-coupled receptor (GPCR) family and plays an essential role in the control of energy homeostasis. Here, we identified a novel MC4R-interacting protein, glucose-regulated protein 78 (GRP78), from a pulldown assay using hypothalamic protein extracts and the third intracellular loop of MC4R. We found that MC4R interacted with GRP78 in both the cytosol and at the cell surface and that this interaction increased when MC4R was internalized in the presence of the agonist melanotan-II (MTII).
View Article and Find Full Text PDFTraumatic brain injury (TBI) is an intracranial injury which can induce immediate neuroinflammation and long-term neurological deficits. Methylene blue (MB) as a nootropic has a great potential to treat neurodegeneration after TBI because of its anti-inflmmatory and neuroprotective functions. However, its limited accumulation to the brain across the blood-brain barrier (BBB) remains a major hurdle to be overcome.
View Article and Find Full Text PDFBiochem Biophys Res Commun
July 2018
The CD133 antigen, also known as prominin-1, is a glycoprotein that specifically localizes to plasma membrane protrusions. The precise function of CD133 remains unknown, but it is expressed in various progenitor cells including those derived from the neural and hematopoietic system, as well as different tissues. In the adult mouse brain, CD133 is highly expressed in white matter.
View Article and Find Full Text PDFA correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
View Article and Find Full Text PDFDopaminergic systems play a major role in reward-related behavior and dysregulation of dopamine (DA) systems can cause several mental disorders, including depression. We previously reported that dopamine D2 receptor knockout (D2R) mice display increased anxiety and depression-like behaviors upon chronic stress. Here, we observed that chronic stress caused myelin loss in wild-type (WT) mice, while the myelin level in D2R mice, which was already lower than that in WT mice, was not affected upon stress.
View Article and Find Full Text PDFRepetitive exposure to addictive drugs causes synaptic modification in the mesocorticolimbic dopamine (DA) system. Dopamine D1 receptors (D1R) or D2 receptors (D2R) expressed in the medium spiny neurons (MSNs) of the nucleus accumbens (NAc) play critical roles in the control of addictive behaviors. Optogenetic activation of D2R-expressing MSNs (D2R-MSNs) in the NAc previously demonstrated that these neurons play a key role in withdrawal-induced plasticity.
View Article and Find Full Text PDFMisfolded polypeptides are rapidly cleared from cells via the ubiquitin-proteasome system (UPS). However, when the UPS is impaired, misfolded polypeptides form small cytoplasmic aggregates, which are sequestered into an aggresome and ultimately degraded by aggrephagy. Despite the relevance of the aggresome to neurodegenerative proteinopathies, the molecular mechanisms underlying aggresome formation remain unclear.
View Article and Find Full Text PDFThe transforming growth factor-β (TGF-β) signaling pathway is associated with carcinogenesis and various biological processes. SMAD2 and SMAD4, which are putative tumor suppressors, have an important role in TGF-β signaling. The aberrant expression of these genes is implicated in some cancers.
View Article and Find Full Text PDFMicroRNAs (miRNAs) are short RNA molecules that control the expression of mRNAs associated with various biological processes. Therefore, deregulated miRNAs play an important role in the pathogenesis of diseases. Numerous studies aimed at developing novel miRNA-based drugs or determining miRNA functions have been conducted by inhibiting miRNAs using anti-miRNA oligonucleotides (AMOs), which inhibit the function by hybridizing with miRNA.
View Article and Find Full Text PDFEndocrinol Metab (Seoul)
December 2015
Background: The melanocortin 4 receptor (MC4R) is involved in the regulation of homeostatic energy balance by the hypothalamus. Recent reports showed that MC4R can also control the motivation for food in association with a brain reward system, such as dopamine. We investigated the expression levels of MC4R and the dopamine D2 receptor (D2R), which is known to be related to food rewards, in both the hypothalamus and brain regions involved in food rewards.
View Article and Find Full Text PDFDopamine (DA) signaling via DA receptors is known to control hippocampal activity that contributes to learning, memory, and synaptic plasticity. In primary hippocampal neuronal culture, we observed that dopamine D2 receptors (D2R) co-localized with certain subtypes of GABAA receptors, namely α1, β3, and γ2 subunits, as revealed by double immunofluorocytochemical analysis. Treatment with the D2R agonist, quinpirole, was shown to elicit an increase in phosphorylation of extracellular signal-regulated kinase (ERK) in hippocampal neurons.
View Article and Find Full Text PDFLong-lasting, drug-induced adaptations within the nucleus accumbens (NAc) have been proposed to contribute to drug-mediated addictive behaviors. Here we have used an optogenetic approach to examine the role of NAc medium spiny neurons (MSNs) expressing dopamine D2 receptors (D2Rs) in cocaine-induced behavioral sensitization. Adeno-associated viral vectors encoding channelrhodopsin-2 (ChR2) were delivered into the NAc of D2R-Cre transgenic mice.
View Article and Find Full Text PDFAbnormal tau aggregation is a pathological hallmark of many neurodegenerative disorders and it is becoming apparent that soluble tau aggregates play a key role in neurodegeneration and memory impairment. Despite this pathological importance, there is currently no single method that allows monitoring soluble tau species in living cells. In this regard, we developed a cell-based sensor that visualizes tau self-assembly.
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