Dopamine Receptor Expression Research Articles

Effort-based decision making in response to high-dose androgens: role of dopamine receptors.

Anabolic-androgenic steroids (AAS) are performance-enhancing drugs used by both world-class and rank-and-file athletes. AAS abuse has been linked with risky decision-making, ranging from drunk driving to abusing multiple drugs. Our lab uses operant behavior in rats to test the effects of AAS (testosterone) on decision making. In our previous study, testosterone caused rats to work harder for food reward during an effort discounting (ED) task. ED is sensitive to dopamine in the nucleus accumbens, and AAS alter accumbens dopamine receptor expression. Accordingly, we determined if testosterone increases response to dopamine receptor antagonists during ED. Rats were treated chronically with high-dose testosterone (7.5 mg/kg; n = 9) or vehicle (n = 9). We measured baseline preference for the large reward in an ED task, where rats choose between a small easy reward (one lever press for one sugar pellet) and a large difficult reward (2, 5, 10, or 15 presses for three pellets). Preference for the large reward was measured after administration of D1-like (SCH23390, 0.01 mg/kg) or D2-like (eticlopride, 0.06 mg/kg) receptor antagonists. At baseline, testosterone- and vehicle-treated rats showed similar preference for the large reward lever (FR5, testosterone: 68.6 ± 9.7% and vehicle: 85.7 ± 2.5%). SCH23390 reduced large reward preference significantly in both groups (FR5, testosterone: 41.3 ± 9.2%; vehicle: 49.1 ± 8.2%; F(1,16) = 17.7; P < 0.05). Eticlopride decreased large reward preference in both groups, but more strongly in testosterone-treated rats (FR5: testosterone: 37.0 ± 9.7%; vehicle: 56.3 ± 7.8%; F(1,16) = 35.3; P < 0.05). Testosterone increases response to dopamine D2-like receptor blockade, and this contributes to previously observed changes in decision-making behaviors.

Boldness in Zebrafish Larvae—Development and Differences between a Domesticated Lab Strain and Offspring of Wild-Caught Fish

Zebrafish (Danio rerio) are becoming one of the most important model organisms in behavioural neuroscience. It has been shown repeatedly that different zebrafish strains show large behavioural differences. These divergent behavioural profiles may have a genetic basis, but environmental factors and previous experience are also known to greatly affect the behavioural phenotype of zebrafish. It could be expected that behavioural differences at the larval stage should be less affected by environmental factors and experience. In the present study, we screened larvae of zebrafish of the AB strain and offspring of wild-caught zebrafish for boldness, using an open field test. In order to follow the behavioural development, we studied larvae at the age of 5-, 7-, 12- and 30-days post fertilization (dpf). Behaviour, as well as behavioural development, clearly differed between the larvae of the different strains. Wild larvae showed larger total distance moved than AB larvae, both at light and dark conditions. These differences were already present at 12 dpf but became more pronounced with age. Wild larvae had a greater variance compared to AB larvae for most of the variables. We have previously shown that bold and shy adult zebrafish differ in the brain expression of dopamine and opioid receptors. The results of the current study show that wild larvae display significantly higher brain expression of drd2b than AB larvae at 30 dpf, a difference that could be related to differences in activity. We did not detect any differences in the expression of opioid receptors.

Dopamine Receptors Gene Expression Pattern and Locomotor Improvement Differ Between Female and Male Zebrafish During Spinal Cord Auto Repair.

The dopaminergic system, a spinal cord (SC) motor circuit regulator, is administrated by sexual hormones and evolutionary conserved in all vertebrates. Accordingly, we hypothesized that the dopamine receptor (DAR) expression pattern may be dissimilar in female and male zebrafish SC auto repair. We implemented an uncomplicated method to induce spinal cord injury (SCI) on fully reproductive adult zebrafish, in both genders. SCI was induced using a 28-gauge needle at 9th-10th vertebra without skin incision. Thereupon, lesioned SC was harvested for DAR gene expression analysis; zebrafish were tracked routinely for any improvement in swim distance, speed, and their roaming capabilities/preference. Our findings revealed discrepancies between drd2a, drd2b, drd3, drd4a, and drd4b expression patterns at 1, 7, and 14 days postinjury (DPI) between female and male zebrafish. The receptors were mostly upregulated at 7 DPI in both genders, whereas drd2a and drd2b were mostly maximized in females. Surprisingly, drd3 was measured greater even in intact SC in males. In addition, female zebrafish were able to swim farther distances more accelerated, in multiple directions, by engaging more caudal muscles compared with males, of course with no statistical significance. Indeed, females were able to generate whole-body rotation and move forward using the muscles downstream to the lesion site, whereas the coordinated movement in males was accomplished by rostral muscles. In conclusion, there are differences in DAR gene expression pattern throughout SC autonomous recovery between adult female and male zebrafish, and also, female locomotion seems to ameliorate more rapidly.

Probiotics (Bacillus clausii and Lactobacillus fermentum NMCC-14) Ameliorate Stress Behavior in Mice by Increasing Monoamine Levels and mRNA Expression of Dopamine Receptors (D1 and D2) and Synaptophysin.

Stress is a physiological consequence of the body to adversity. The gut–brain axis and probiotics are gaining interest to provide better treatment for stress and other neurological disorders. Probiotic (Lactobacillus fermentum NMCC-14 and Bacillus clausii, 1010 colony-forming unit/day/animal, per oral) effects were investigated in acute (up to day 7) and subacute (days 8–14) restraint-stressed and normal mice through behavioral paradigms (elevated plus maze: EPM, light dark box/dark light box: LDB, and open field test: OFT). Time spent in the open arms of the EPM, time spent in the light compartment of the LDB, and movable time and time spent in the center of the OFT were significantly (p ≤ 0.05, n = 5) increased in probiotic-treated restraint-stressed mice. Enzyme-linked immunoassay determined blood cortisol and adrenocorticotropic hormone (ACTH) levels, which were reduced significantly (p < 0.05, n = 5) in probiotic-treated restraint-stressed mice. Hematoxylin and eosin-stained hippocampal slides also showed less or no neurodegeneration in the probiotic-treated animals. High-performance liquid chromatography and quantitative polymerase chain reaction were performed to determine the monoamine levels and mRNA expression of dopamine receptor subtypes (D1 and D2) and synaptophysin in the mice hippocampus (HC) and prefrontal cortex (PFC). The dopamine, serotonin, and norepinephrine levels were also significantly (p < 0.05, n = 5) increased in the HC and PFC of probiotic-treated animal brains. Fold expression of mRNA of D1 and D2 (except HC, LF-S, day 14) receptors and synaptophysin was also significantly (p < 0.05, n = 5) increased in the same brain parts of probiotic-treated restraint-stressed mice. Comparing mice in the Lactobacillus fermentum NMCC-14 and Bacillus clausii groups to mice in the normal group, only a significant (p < 0.05, n = 5) decrease was observed in the serum ACTH and cortisol levels on day 14 in Bacillus clausii-treated mice, where all other parameters also showed improvement. In comparison, Bacillus clausii showed greater stress suppressant activity than Lactobacillus fermentum NMCC-14. However, both probiotic bacteria can be a better and safer therapeutic alternative for ailments than currently available drugs.

Prolonged breastfeeding protects from obesity by hypothalamic action of hepatic FGF21

Early-life determinants are thought to be a major factor in the rapid increase of obesity. However, while maternal nutrition has been extensively studied, the effects of breastfeeding by the infant on the reprogramming of energy balance in childhood and throughout adulthood remain largely unknown. Here we show that delayed weaning in rat pups protects them against diet-induced obesity in adulthood, through enhanced brown adipose tissue thermogenesis and energy expenditure. In-depth metabolic phenotyping in this rat model as well as in transgenic mice reveals that the effects of prolonged suckling are mediated by increased hepatic fibroblast growth factor 21 (FGF21) production and tanycyte-controlled access to the hypothalamus in adulthood. Specifically, FGF21 activates GABA-containing neurons expressing dopamine receptor 2 in the lateral hypothalamic area and zona incerta. Prolonged breastfeeding thus constitutes a protective mechanism against obesity by affecting long-lasting physiological changes in liver-to-hypothalamus communication and hypothalamic metabolic regulation.

Analysis of the Expression of Dopamine Receptors, DRD1 and DRD5, in Cancerous Tissue of Patients with Breast Cancer and the Impact of Quercetin on the Expression of These Receptors in Hs578t and HDF Cell Lines

Background &amp; Objectives: The expression of neurotransmitters during cancer progression is one of the factors to consider. This study aimed to evaluate the possible expression changes in dopamine receptors (DRD1 and DRD5), in breast tumor tissue compared to healthy adjacent samples, and the effect of quercetin on the expression of these receptors.&#x0D; Materials &amp; Methods: Expression levels of DRD1 and DRD5 were evaluated in 20 breast tumors and healthy adjacent samples using qPCR. The RNA was extracted from all samples, followed by cDNA synthesis and real-time PCR. In vitro experiment was accomplished on breast cancer cell line, Hs578t. Cells were treated with quercetin and evaluated cell viability by MTT assay. DRD1 and DRD5 gene expression was performed in treatment cells compared to untreated control. Statistical analysis was performed to determine the significance.&#x0D; Results: The results showed that the DRD1 and DRD5 were unregulated in breast cancer tissue (p&lt;0.01). For cellular experiment, MTT assays revealed that the quercetin induced a significant decrease in cell viability and proliferation in dose and time-dependent but it was not seen in a normal cell line (HDF). Hs578t cells showed a significant reduction of DRD5 in response to quercetin. DRD1 gene downregulation was indicated significant in 72h treatment.&#x0D; Conclusions: The effect of quercetin on the expression of genes encoding DRD1 and DRD5 showed that this substance reduced the expression of these two genes in treated Hs578t cells compared to untreated cells in the same cell line.

Effect of chronic stress on the relative level of dopamine receptor gene expression

Background. The regulation of the central dopaminergic system under the influence of chronic stress is disturbed, however, the dynamics of changes in the dopamine receptors expression in the periphery remains poorly understood.&#x0D; Aim. Evaluation of the different models of chronic stress influence on changes in the relative level of dopamine receptor gene expression in peripheral blood cells of rats during immobilization and intense physical activity.&#x0D; Material and methods. For 270 days on 88 Wistar rats, the study on the effect of different models of chronic stress on the change in the relative level of Drd15 genes expression was performed in four groups: the first control group; the second group was subjected to intensive physical activity in the Forced swimming with a load test (7-minute swimming with a load of 8% of body weight 2 times a week); the third group experienced daily 90-minute immobilization for 14 days; the fourth group had combined exposure of physical activity and immobilization. The relative level of dopamine receptor gene expression was determined by real-time polymerase chain reaction after 90, 180, and 270 days of the experiment in peripheral blood cells of the tail vein. The calculation of the relative level of gene expression was carried out based on the Livak method (2Ct); the assessment of the difference significance using a two-sample t-test for independent samples.&#x0D; Results. The analysis of the relative level of genes encoding D1-type dopamine receptors expression showed that a decrease in the Drd1 gene expression level after 90 days of the experiment was detected only in male rats from immobilization stress and control groups [RQ 0.35 (p=0.003) and 0.21 (p=0.002), respectively], while in males from other groups and females, the activity of this gene did not change significantly throughout the course of the experiment. The relative expression level of Drd5 gene changed only in female rats. In females subjected to intense physical activity, the level of this gene expression increased almost 4 times (RQ 3.82, p=0.005) 90 days after the start of the experiment, and in females of the control group, the transcriptional activity of the gene decreased 4 times after 180 days of the experiment (RQ 0.25, p=0.015). When assessing changes in the activity of genes encoding D2-type receptors for the Drd3 and Drd4 genes, a significant increase in the relative expression level was revealed in all experimental groups, both in males and females, on the 180th day of exposure to stress factors. At the same time, activation of both genes was occurred after 90 days in the control group only in females and persisted up to another 90 days, after which it returned to the initial level. Expression of the Drd2 gene wasn't detected in rat blood cells.&#x0D; Conclusion. The relative level of expression of D1- and D2-like receptor genes in rat peripheral blood cells depends on the type of chronic stress and has pronounced sexual dimorphism.

Clinical effects of Cariprazine and their relationship with polymorphisms of dopamine and serotonin receptors: preliminary results from a prospective study on schizophrenia and bipolar disorder

IntroductionCariprazine (CAR) is a D2, D3, 5HT1A receptor partial agonist and a 5HT2A, 5HT2B antagonist, used to treat Schizophrenia and Bipolar disorder. Interindividual variability in therapeutic and side effects of antipsychotics is difficult to predict, due to non-genetic and genetic factors. Single nucleotide polymorphisms (SNPs) are the main source of genetic variability, the ones in dopamine and serotonin receptors to which CAR binds are indeed likely to determine response to treatment.ObjectivesThe aim of the study is to define a relationship between CAR clinical efficacy and SNPs in dopamine and serotonin receptors genes of patients affected by schizophrenia and bipolar disorder.MethodsWe recruited 16 patients starting a monotherapy with CAR, evaluated at baseline and after 2, 4 and 8 weeks through BPRS rating scale. We selected a panel of SNPs in DR2, DR3, 5HT1A and 5HT2A receptors, with a frequency higher that 10% in Caucasians and functionally characterized. Cut-off for response to treatment was a 50% reduction of BPRS score. Statistical analysis was performed with one-way ANOVA followed by the test for linear trend between columns.ResultsAll subjects achieved response after 8 weeks of treatment, but 6 patients after 4 weeks. Early responders have a genetic profile associated with increased dopamine and serotonin receptor expression and/or binding affinity for their specific ligands. The association don’t reach statistical significance, probably due to low number of patients.ConclusionsPreliminary results suggest that an array of dopamine and serotonin receptors SNPs could predict time to respond to CAR in schizophrenia and bipolar disorder.DisclosureThe study is founded by Recordati AG, that commercialize the drug under study (Cariprazine) in Switzerland. Funding covers the costs for genetic analysis and other procedures of the study, no financial compensation is planned for investigators/authors.

Dopamine Reduces SARS-CoV-2 Replication In Vitro through Downregulation of D2 Receptors and Upregulation of Type-I Interferons.

Recent evidence suggests that SARS-CoV-2 hinders immune responses via dopamine (DA)-related mechanisms. Nonetheless, studies addressing the specific role of DA in the frame of SARS-CoV-2 infection are still missing. In the present study, we investigate the role of DA in SARS-CoV-2 replication along with potential links with innate immune pathways in CaLu-3 human epithelial lung cells. We document here for the first time that, besides DA synthetic pathways, SARS-CoV-2 alters the expression of D1 and D2 DA receptors (D1DR, D2DR), while DA administration reduces viral replication. Such an effect occurs at non-toxic, micromolar-range DA doses, which are known to induce receptor desensitization and downregulation. Indeed, the antiviral effects of DA were associated with a robust downregulation of D2DRs both at mRNA and protein levels, while the amount of D1DRs was not significantly affected. While halting SARS-CoV-2 replication, DA, similar to the D2DR agonist quinpirole, upregulates the expression of ISGs and Type-I IFNs, which goes along with the downregulation of various pro-inflammatory mediators. In turn, administration of Type-I IFNs, while dramatically reducing SARS-CoV-2 replication, converges in downregulating D2DRs expression. Besides configuring the CaLu-3 cell line as a suitable model to study SARS-CoV-2-induced alterations at the level of the DA system in the periphery, our findings disclose a previously unappreciated correlation between DA pathways and Type-I IFN response, which may be disrupted by SARS-CoV-2 for host cell invasion and replication.

Dopamine receptor signaling regulates fibrotic activation of retinal pigmented epithelial cells.

Retinal pigmented epithelial (RPE) cells play an important role in retinal fibrotic diseases such as proliferative vitreoretinopathy (PVR). The purpose of this study was to elucidate the involvement of dopamine receptor signaling in regulating the fibrotic activation of RPE cells. Dopamine receptor expression, the effect of dopamine on fibrotic activity, and dopamine production were measured in the human RPE cell line ARPE-19. The fibrotic activation of RPE cells was evaluated in response to treatments with selective dopamine receptor agonists and antagonists by measuring gene expression, migration, proliferation, and fibronectin deposition. DRD2 and DRD5 are the dominant dopaminergic receptors expressed in ARPE-19 cells and TGF-β stimulation enhances the autocrine release of dopamine, which we show further exasperates fibrotic activation. Finally, treatment with D2 dopamine receptor antagonists or D5 dopamine receptor agonists inhibits profibrotic gene expression, migration, proliferation, and fibronectin deposition and thus may serve as effective mechanisms for treating retinal fibrosis including PVR.

Modulation of Dopamine Receptors on Osteoblasts as a Possible Therapeutic Strategy for Inducing Bone Formation in Arthritis.

Rheumatoid arthritis (RA) is associated with systemic osteoporosis, which leads to severe disability and low quality of life. Current therapies target osteoclasts to reduce bone degradation, but more treatment options would be required to promote bone protection by acting directly on osteoblasts (OB). Recently, the local production of dopamine in inflamed joints of RA has been observed. Thus, in this project, we aimed to determine the implication of the neurotransmitter dopamine in the bone formation process in RA. Dopamine receptors (DR) in the human bone tissue of RA or osteoarthritis (OA) patients were examined by immunohistochemistry. DR in isolated human osteoblasts (OB) was analyzed by flow cytometry, and dopamine content was evaluated by ELISA. Osteoclasts (OC) were differentiated from the PBMCs of healthy controls (HC) and RA patients. Isolated cells were treated with specific dopamine agonists. The effect of dopamine on mineralization was evaluated by Alizarin red staining. Cytokine release in supernatants was measured by ELISA. Osteoclastogenesis was evaluated with TRAP staining. OC markers were analyzed via real-time PCR and bone resorption via staining of resorption pits with toluidine blue. All DR were observed in bone tissue, especially in the bone remodeling area. Isolated OB maintained DR expression, which allowed their study in vitro. Isolated OB expressed tyrosine hydroxylase, the rate-limiting enzyme for dopamine production, and contained dopamine. The activation of D2-like DR significantly increased bone mineralization in RA osteoblasts and increased osteoclastogenesis but did not alter the expression of OC markers nor bone resorption. DR were found in the bone remodeling area of human bone tissue and dopamine can be produced by osteoblasts themselves, thus suggesting a local autocrine/paracrine pathway of dopamine in the bone. D2-like DRs are responsible for bone mineralization in osteoblasts from RA patients without an increase in bone resorption, thus suggesting the D2-like DR pathway as a possible future therapeutic target to counteract bone resorption in arthritis.

Dopamine‐driven Increase in IL‐1β in Myeloid Cells is Mediated by Differential Dopamine Receptor Expression and Exacerbated by HIV

The neurological complications of HIV infection, known as neuroHIV, remain prevalent even in individuals on antiretroviral therapy (ART). Although the mechanism(s) underlying neuroHIV remain undefined, current data suggest that neuroinflammation is central to the development of HIV neuropathogenesis. Neuroinflammation can be exacerbated by substance use disorders, which are highly comorbid with HIV infection and substantively worsen clinical outcomes. Despite distinct mechanisms of action, all substances of abuse increase central nervous system (CNS) dopamine, suggesting that dopamine is a common mechanism by which addictive drugs potentiate neuroHIV. Our published data show that dopamine increases the production of inflammatory cytokines such as IL‐1β in human microglia and macrophages, but the mechanisms by which dopamine drives inflammation are not clear. Studies indicate that D1‐like dopamine receptors (DRD1, DRD5) mediate inflammatory activity while D2‐like dopamine receptors (DRD2, DRD3, and DRD4) mediate anti‐inflammatory activity, and we have shown that human macrophages and microglia have higher expression of D1‐like receptors. Therefore, we hypothesize that dopamine‐mediated production of IL‐1β in CNS myeloid cells is regulated by the ratio of different dopamine receptor expression levels and can be exacerbated by HIV infection. Our data in primary macrophages indicate that DRD1 expression is necessary for dopamine‐mediated increases in IL‐1β, but that changes in DRD2 expression can alter the magnitude of the dopamine‐mediated increase in IL‐1β. We confirm this in human microglia cell lines, showing that dopamine only increases IL‐1β gene and protein expression in microglia with a high ratio of D1‐like receptors to D2‐like receptors. Further, antagonizing dopamine receptor expression with the pan‐dopamine receptor antagonist flupentixol or decreasing the D1‐like/D2‐like ratio by overexpressing DRD2 diminishes the dopamine‐mediated increase of IL‐1β. We also show that the effects of dopamine on IL‐1β are potentiated in the presence of HIV infection in both microglial cell lines and iPSC‐derived microglia. Ongoing studies are examining the role of epigenetic regulation in the effects of dopamine and HIV on inflammation in these myeloid systems.Due to the prevalence of both substance use disorders and the increasing use of dopamine‐modulating therapeutics, a detailed understanding of dopamine‐mediated changes in inflammation will be critical to effectively tailor ART regimens to HIV‐infected individuals using these drugs.

Defining Dopamine‐Mediated Changes in NLRP1, NLRC5, NLRC4, and AIM2 Inflammasomes in Human Myeloid Cells

Although the study of dopamine is most often associated with the regulation of reward and motor function, a growing body of research indicates that dopamine also acts as an immunomodulatory regulator. Our data show that dopamine can influence the secretion of inflammatory cytokines in myeloid cells such as macrophages and microglia. Specifically, we have shown that dopamine modulates inflammation in primary human monocyte‐derived macrophages (hMDM) through activation of the transcription factor NF‐κB and priming of the NLRP3 inflammasome, upregulating the expression of IL‐1 family cytokines (IL‐1β and IL‐18). However, the effect of dopamine on other proteins in the NLR family, including NLRP1, NLRC4, NLRC5, and AIM2, has not been defined. Each NLR protein is associated with a different inflammasome complex that has distinct activating stimuli, yet all inflammasomes mediate the secretion of IL‐1 family cytokines. We hypothesize that the effects of dopamine on different types of inflammasomes is distinct and may result in activation of discrete inflammatory pathways and/or differentially regulate cytokine secretion. To address this, we examined dopamine‐mediated changes in NLR proteins in both hMDM and a human microglial cell line (C20 cells). Our data indicate that in hMDM, dopamine upregulates expression of NLRC5, NLRC4, and AIM2 transcripts, while not changing NLRP1 mRNA expression. However, in microglia there was no expression of NLRC4 or AIM2, and dopamine downregulates NLRP1, while not changing NLRC5 mRNA expression. Ongoing work is using high‐content immunofluorescent imaging and Western blotting to analyze inflammasome protein expression in these myeloid cell models and determine how this correlates with NLR gene expression as well as dopamine receptor expression. Determining how dopamine affects NLR expression could improve our understanding of the role of dopamine and its receptors as drug targets in individuals with substance use disorders. Further, the activity of these inflammasomes is associated with a number of neuroimmunological diseases such as Parkinson’s, Alzheimer’s, multiple sclerosis and HIV that show disrupted dopamine signaling. Therefore, understanding the more specific immunologic actions of dopamine could initiate drug repurposing and the development of new therapeutic strategies based on manipulating dopamine’s effects on the immune system.

Characterization of a Nociceptive Neural Ensemble in the Nucleus Accumbens Shell

The experience of pain encompasses both nociceptive sensory and negative affective dimensions. A key first step to understand the affective dimension is to functionally and genetically identify nociceptive neurons connected across affective-motivational neural circuits in acute and chronic pain states. We recently identified a nociceptive subpopulation of negative valence basolateral amygdala (BLA) neurons essential for pain aversion. Here, we characterize a downstream target of BLA nociceptive neurons—the nucleus accumbens Shell (NAcSh). Broadly, aberrant activity of the NAcSh has been linked to motivational deficits in chronic pain, yet much remains unknown regarding specific NAcSh nociceptive cell-types or their modulation by BLA nociceptive neurons. Here, we used targeted recombination in active populations (TRAP) mice to genetically capture nociceptive NAcSh neurons (nociTRAP) with combined immunohistochemistry, fluorescent in situ hybridization (FISH), and viral tract tracing. We identified a previously unreported posterior medial NAcSh subregion—anatomically encompassed by the Islands of Cajella granule cell clusters—that contains numerous nociTRAP neurons. This region, which we termed the "NAcre" (named after the inner shell layer of mollusks), receives projections from nociceptive BLA neurons. Importantly, the majority of acute nociTRAP NAcre neurons also display increased immediate early gene FOS expression to light touch following a peripheral nerve injury, revealing consistent activation across pain states independent of stimulus sensory modality. Finally, using multiplexed FISH, we found that nociTRAP NAcre neurons, while molecularly heterogeneous, were primarily medium spiny neurons expressing dopamine receptor 2 and kappa opioid receptor mRNA. In total, the NAcre is a highly nociceptive subregion of the posterior medial NAcSh that receives nociceptive transmissions from the BLA and may be involved in pain-related kappa opioid aversion processes. Further work will determine the necessity and sufficiency of this neural population for affective-motivational behaviors in acute and chronic pain states. Grant support from 5R00DA043609-04 - Deconstructing the network mechanisms of chronic pain and reward in the amygdala (Independent Phase).

How do maternal emotion and sleep conditions affect infant sleep: a prospective cohort study

BackgroundRecent studies suggest that the incidence of infant sleep disorder is related to maternal emotional and sleep conditions, but how they influence each other is not fully understood.MethodsA total of 513 pairs of parents and infants were enrolled in this prospective cohort study. Maternal emotional and sleep conditions were assessed using a self-rating depression scale, self-rating anxiety scale, and Pittsburgh Sleep Quality Index at the third trimester and within 3 months after delivery. Infant sleep was assessed by the Brief Screening Questionnaire for Infant Sleep Problems within 3 months after birth. Expression of the glucocorticoid receptor (GR), melatonin receptors (MR), exchange proteins directly activated by cAMP (EPAC) receptors, and dopamine receptor (DR) in the placenta was detected by immunohistochemistry. Methylation of the promoter regions for the GR (NR3C1 and NR3C2), MR (MTNR1A and MTNR1B), EPAC (RASGRF1 and RASGRF2), and DR (DRD1 and DRD2) genes was assessed by next generation sequencing-based bisulfite sequencing PCR.ResultsThe incidence of sleep disorders in infants 0–3 months of age in this cohort was 40.5%. Risk factors for infant sleep disorder were low education level of the father, depression of father, maternal postpartum depression, postpartum anxiety, postpartum sleep disorder, and maternal sleep disorder extend from the third trimester to postpartum. There was no difference in expression of placental DR, GR, MR, and EPAC between mothers whose infants were with and without sleep disorders. Methylation of MTNR1B was higher and expression of MR was lower in the placenta of mothers with sleep disorder in the third trimester than in mothers without sleep disorder. Level of NR3C2 methylation was lower and GR expression was higher in the placenta of mothers with sleep disorder extend from the third trimester to postpartum than in mothers without sleep disorder.ConclusionMaternal sleep disorders in the third trimester could lead to decreased MR expression by up-regulating MTNR1B methylation, and then resulting in elevated cortisol and increased GR expression by down-regulating NR3C2 methylation, which could increase the incidence of maternal postpartum sleep disorders, finally, the maternal postpartum sleep disorder could result in the high incidence of infant sleep disorder.

Calorie restriction changes the anxiety-like behaviour of ageing male Wistar rats in an onset- and duration-dependent manner

Although initially recognized as a universally beneficial approach for the prevention of age-related impairments, the outcome of calorie restriction (CR) is now known to depend on several factors, most notably the age of the subject at the CR commencement, and CR duration. We aimed to examine if and how CR affects anxiety-like behaviour when it is introduced at middle age and late middle age. In addition, as the dopaminergic system is one of the main neurotransmitter systems involved in controlling anxiety, we examined the expression of dopamine receptors (D1R, D2R) in the cortex, striatum, and mesencephalon of male Wistar rats of varying ages. The study was performed on rats fed ad libitum (AL) or exposed to calorie restriction (60% of AL intake). Open field and light-dark tests were used to study anxiety-like behaviour, while PCR and Western blot were used to examine the expression of dopamine receptors. Calorie restriction implemented at middle-age led to variable outcomes on anxiety-like behaviour, while CR implemented at late middle age increased anxiety and decreased the availability of D2R levels in the cortex and mesencephalon. Taken together, these results advise caution when implementing calorie restriction late in life.

Novel Small-Molecule Inhibitor of NLRP3 Inflammasome Reverses Cognitive Impairment in an Alzheimer's Disease Model.

Aberrant activation of the Nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome plays an essential role in multiple diseases, including Alzheimer's disease (AD) and psoriasis. We report a novel small-molecule inhibitor, NLRP3-inhibitory compound 7 (NIC7), and its derivative, which inhibit NLRP3-mediated activation of caspase 1 along with the secretion of interleukin (IL)-1β, IL-18, and lactate dehydrogenase. We examined the therapeutic potential of NIC7 in a disease model of AD by analyzing its effect on cognitive impairment as well as the expression of dopamine receptors and neuronal markers. NIC7 significantly reversed the associated disease symptoms in the mice model. On the other hand, NIC7 did not reverse the disease symptoms in the imiquimod (IMQ)-induced disease model of psoriasis. This indicates that IMQ-based psoriasis is independent of NLRP3. Overall, NIC7 and its derivative have therapeutic prospects to treat AD or NLRP3-mediated diseases.

Activation of dopamine receptor D1 promotes osteogenic differentiation and reduces glucocorticoid-induced bone loss by upregulating the ERK1/2 signaling pathway

BackgroundThe inhibition of osteogenic differentiation is a major factor in glucocorticoid-induced bone loss, but there is currently no effective treatment. Dopamine, a major neurotransmitter, transmits signals via five different seven-transmembrane G protein-coupled receptors termed D1 to D5. Although the relevance of the neuroendocrine system in bone metabolism has emerged, the precise effects of dopamine receptor signaling on osteoblastogenesis remain unknown.MethodsIn vitro, western blotting and immunofluorescence staining were used to observe the expression of dopamine receptors in MC3T3-E1 and BMSCs cells treated with dexamethasone (Dex). In addition, Alizarin red S (ARS) and alkaline phosphatase (ALP) staining and western blotting were used to evaluate the effect of D1R activation on osteogenic differentiation in Dex-induced MC3T3-E1 cells via the ERK1/2 signaling pathway. In vivo, micro-CT and hematoxylin and eosin (H&E), toluidine blue and immunohistochemical staining were used to determine the effect of D1R activation on Dex-induced bone loss.ResultsWe demonstrated that the trend in D1R but not D2-5R was consistent with that of osteogenic markers in the presence of Dex. We also demonstrated that the activation of D1R promoted Dex-induced osteogenic differentiation by activating the ERK1/2 pathway in vitro. We further demonstrated that a D1R agonist could reduce Dex-induced bone loss, while pretreatment with a D1R inhibitor blocked the effect of a D1R agonist in vivo.ConclusionsActivation of D1R promotes osteogenic differentiation and reduces Dex-induced bone loss by activating the ERK1/2 pathway. Hence, D1R could serve as a potential therapeutic target for glucocorticoid-induced osteoporosis.

Adolescent chronic unpredictable stress causes a bias in goal-directed behavior and distinctively changes the expression of NMDA and dopamine receptors in the dorsomedial and dorsolateral striatum in male rats.

The distinct preferences between goal-directed and habit-directed behaviors involve numerous neurodegenerative and psychiatric disorders. Chronic stress during adulthood biases behavior toward habit-oriented strategies. However, it remains to be studied how adolescence, as a stage in which brain regions are still undergoing development, suffering stress will affect this preference. Here, we exposed rats to chronic unpredictable stress (CUS) at PND 21 to PND 33 and PND 34 to PND 47 to examine its effect on sugar pellet-based instrumental behavior in adulthood. We showed that rats exposed to CUS in middle adolescence had a biased goal-directed strategy rather than a habit-oriented strategy in adulthood, whereas CUS exposure in early adolescence did not have this effect. Moreover, middle adolescent CUS caused the downregulation of the N-methyl-d-aspartate receptor subtype 2 B (NR2B) in the dorsolateral striatum (DLS) rather than in the dorsomedial striatum (DMS), whereas no change was observed in NR2A or the dopamine D1 receptor (D1R) or the dopamine D2 receptor (D2R) in the DLS. Together, these findings suggest that CUS in middle adolescence inhibits habitual behavior in adulthood and downregulates the expression of NR2B in DLS, providing new evidence to understand the molecular mechanisms of abnormal habitual behaviors induced by adolescent stress.

Prenatal Amphetamine-Induced Dopaminergic Alteration in a Gender- and Estrogen-Dependent Manner.

Prenatal exposure to amphetamine induces changes in dopamine receptors in mesolimbic areas and alters locomotor response to amphetamine during adulthood. Sex differences have been reported in amphetamine-induced brain activity and stress sensitivity. We evaluated the effects of prenatal amphetamine exposure on locomotor activity, dopamine receptors and tyrosine hydroxylase mRNA expression in nucleus accumbens and caudate-putamen in response to amphetamine challenge in adult female and male rats. The role of estrogen in the response to restraint stress was analyzed in ovariectomized, prenatally amphetamine-exposed rats. Pregnant rats were treated with D-amphetamine during days 15-21 of gestation. Nucleus accumbens and caudate-putamen were processed for mRNA determination by real-time PCR. In nucleus accumbens, higher mRNA dopamine (D3) receptor expression was found in basal and D-amphetamine-challenge conditions in female than male, and prenatal amphetamine increased the difference. No sex differences were observed in caudate-putamen. Basal saline-treated females showed higher locomotor activity than males. Amphetamine challenge in prenatally amphetamine-exposed rats increased locomotor activity in males and reduced it in females. In nucleus accumbens, estrogen diminished mRNA D1, D2 and D3 receptor expression in basal, and D1 and D3 in ovariectomized stressed rats. Estrogen prevented the increase in tyrosine hydroxylase expression induced by stress in ovariectomized prenatally exposed rats. In conclusion, estrogen modulates mRNA levels of D1, D2 and D3 receptors and tyrosine hydroxylase expression in nucleus accumbens; prenatal amphetamine-exposure effects on D3 receptors and behavioral responses were gender dependent.