RESUMEN
Hibernating mammals actively lower their body temperature to reduce energy expenditure when facing food scarcity1. This ability to induce a hypometabolic state has evoked great interest owing to its potential medical benefits2,3. Here we show that a hypothalamic neuronal circuit in rodents induces a long-lasting hypothermic and hypometabolic state similar to hibernation. In this state, although body temperature and levels of oxygen consumption are kept very low, the ability to regulate metabolism still remains functional, as in hibernation4. There was no obvious damage to tissues and organs or abnormalities in behaviour after recovery from this state. Our findings could enable the development of a method to induce a hibernation-like state, which would have potential applications in non-hibernating mammalian species including humans.
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Metabolismo Energético/fisiología , Hibernación/fisiología , Hipotálamo/citología , Hipotálamo/fisiología , Vías Nerviosas/citología , Vías Nerviosas/fisiología , Animales , Metabolismo Basal/fisiología , Núcleo Hipotalámico Dorsomedial/citología , Núcleo Hipotalámico Dorsomedial/fisiología , Femenino , Neuronas GABAérgicas/metabolismo , Glutamina/metabolismo , Masculino , Ratones , Consumo de Oxígeno/fisiologíaRESUMEN
Unknown interactions between drugs remain the limiting factor for clinical application of drugs, and the induction and inhibition of drug-metabolizing CYP enzymes are considered the key to examining the drug-drug interaction (DDI). In this study, using human HepaRG cells as an in vitro model system, we analyzed the potential DDI based on the expression levels of CYP3A4 and CYP1A2. Rifampicin and omeprazole, the potent inducers for CYP3A4 and CYP1A2, respectively, induce expression of the corresponding CYP enzymes at both the mRNA and protein levels. We noticed that, in addition to inducing CYP1A2, omeprazole induced CYP3A4 mRNA expression in HepaRG cells. However, unexpectedly, CYP3A4 protein expression levels were not increased after omeprazole treatment. Concurrent administration of rifampicin and omeprazole showed an inhibitory effect of omeprazole on the CYP3A4 protein expression induced by rifampicin, while its mRNA induction remained intact. Cycloheximide chase assay revealed increased CYP3A4 protein degradation in the cells exposed to omeprazole. The data presented here suggest the potential importance of broadening the current DDI examination beyond conventional transcriptional induction and enzyme-activity inhibition tests to include post-translational regulation analysis of CYP enzyme expression.
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Citocromo P-450 CYP3A , Interacciones Farmacológicas , Omeprazol , ARN Mensajero , Rifampin , Omeprazol/farmacología , Humanos , Citocromo P-450 CYP3A/metabolismo , Citocromo P-450 CYP3A/genética , Rifampin/farmacología , ARN Mensajero/metabolismo , Inductores del Citocromo P-450 CYP3A/farmacología , Citocromo P-450 CYP1A2/genética , Citocromo P-450 CYP1A2/metabolismo , Citocromo P-450 CYP1A2/biosíntesis , Línea CelularRESUMEN
Temperature-dependent translational control of the core clock gene Per2 plays an important role in establishing entrainment of the circadian clock to physiological body temperature cycles. Previously, we found an involvement of the phosphatidylinositol 3-kinase (PI3K) in causing Per2 protein expression in response to a warm temperature shift (WTS) within a physiological range (from 35 to 38.5 °C). However, signaling pathway mediating the Per2 protein expression in response to WTS is only sparsely understood. Additional factor(s) other than PI3K remains unknown. Here we report the identification of eukaryotic initiation factor 2α (eIF2α) kinases, protein kinase R (PKR) and PKR-like endoplasmic reticulum kinase (PERK), as a novel mediator of WTS-dependent Per2 protein expression. Canonically, eIF2α has been regarded as a major downstream target of PERK and PKR. However, we found that PERK and PKR mediate WTS response of Per2 in a manner not involving eIF2α. We observed that PERK and PKR serve as an upstream regulator of PI3K rather than eIF2α in the context of WTS-dependent Per2 protein expression. There have been studies reporting PI3K activation occurring depending on PERK and PKR, while its physiological contribution has remained elusive. Our finding therefore not only helps to enrich the knowledge of how WTS affects Per2 protein expression but also extends the region of cellular biology involving the PERK/PKR-mediated PI3K activation to include entrainment-mechanism of the circadian clock.
Asunto(s)
Relojes Circadianos , Fosfatidilinositol 3-Quinasas , Temperatura , Regulación hacia Arriba , Biotina , Fosfatidilinositol 3-Quinasa , eIF-2 Quinasa/genéticaRESUMEN
The suprachiasmatic nucleus (SCN), the central circadian pacemaker in mammals, is a network structure composed of multiple types of γ-aminobutyric acid (GABA)-ergic neurons and glial cells. However, the roles of GABA-mediated signaling in the SCN network remain controversial. Here, we report noticeable impairment of the circadian rhythm in mice with a specific deletion of the vesicular GABA transporter in arginine vasopressin (AVP)-producing neurons. These mice showed disturbed diurnal rhythms of GABAA receptor-mediated synaptic transmission in SCN neurons and marked lengthening of the activity time in circadian behavioral rhythms due to the extended interval between morning and evening locomotor activities. Synchrony of molecular circadian oscillations among SCN neurons did not significantly change, whereas the phase relationships between SCN molecular clocks and circadian morning/evening locomotor activities were altered significantly, as revealed by PER2::LUC imaging of SCN explants and in vivo recording of intracellular Ca2+ in SCN AVP neurons. In contrast, daily neuronal activity in SCN neurons in vivo clearly showed a bimodal pattern that correlated with dissociated morning/evening locomotor activities. Therefore, GABAergic transmission from AVP neurons regulates the timing of SCN neuronal firing to temporally restrict circadian behavior to appropriate time windows in SCN molecular clocks.
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Relojes Circadianos , Ritmo Circadiano , Neuronas/metabolismo , Núcleo Supraquiasmático/metabolismo , Vasopresinas/metabolismo , Ácido gamma-Aminobutírico/metabolismo , Animales , Conducta Animal , Calcio/metabolismo , Relojes Circadianos/genética , Ritmo Circadiano/genética , Regulación de la Expresión Génica , Locomoción , Ratones , Sinapsis/fisiología , Transmisión Sináptica/fisiología , Factores de Tiempo , Proteínas del Transporte Vesicular de Aminoácidos Inhibidores/deficiencia , Proteínas del Transporte Vesicular de Aminoácidos Inhibidores/metabolismoRESUMEN
BACKGROUND: Peritoneal dialysis (PD) is an important alternative treatment for end-stage renal disease. Continuous exposure to non-physiological fluids during PD is associated with pathological responses, such as sustained microinflammation, leading to tissue fibrosis and angiogenesis. However, the effect of PD fluid on submesothelial cells has not yet been investigated in detail. METHODS: We investigated the association between macrophages and the expression of matrix metalloproteinase-12 (MMP-12), an elastin proteinase secreted by macrophages, in the peritoneal tissue of rats undergoing continuous PD. RESULTS: Morphological data revealed that the submesothelial layer of the peritoneum in PD model rats was markedly thickened, with fibrosis and angiogenesis. In the fibrillization area, elastin was disorganized and fragmented, and macrophages accumulated, which tended to have M2 characteristics. The expression of MMP-12 was enhanced by continuous exposure to PD fluid, suggesting that MMP-12 expression may be involved in PD fluid-induced peritoneal damage. CONCLUSIONS: The results of this study may lead to a better understanding of the mechanisms underlying fibrosis in PD.
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Diálisis Peritoneal , Peritoneo , Ratas , Animales , Peritoneo/metabolismo , Metaloproteinasa 12 de la Matriz/metabolismo , Metaloproteinasa 12 de la Matriz/farmacología , Elastina/metabolismo , Elastina/farmacología , Soluciones para Diálisis/farmacología , FibrosisRESUMEN
Skeletal muscle is programmable, and early-life nutritional stimuli may form epigenetic memory in the skeletal muscle, thus impacting adult muscle function, aging, and longevity. In the present study, we designed a one-month protein restriction model using post-weaning rats, followed by a two-month rebound feeding, to investigate how early-life protein restriction affects overall body growth and muscle development and whether these influences could be corrected by rebound feeding. We observed comprehensive alterations immediately after protein restriction, including retarded growth, altered biochemical indices, and disturbed hormone secretion. Transcriptome profiling of the gastrocnemius muscle followed by gene ontology analyses revealed that "myogenic differentiation functions" were upregulated, while "protein catabolism" was downregulated as a compensatory mechanism, with enhanced endoplasmic reticulum stress and undesired apoptosis. Furthermore, methylome profiling of the gastrocnemius muscle showed that protein restriction altered the methylation of apoptotic and hormone secretion-related genes. Although most of the alterations were reversed after rebound feeding, 17 genes, most of which play roles during muscle development, remained altered at the transcriptional level. In summary, early-life protein restriction may undermine muscle function in the long term and affect skeletal muscle development at the both transcriptional and methylation levels, which may hazard future muscle health.
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Epigenoma , Transcriptoma , Ratas , Animales , Destete , Dieta con Restricción de Proteínas , Proteínas/metabolismo , Músculo Esquelético/metabolismo , Perfilación de la Expresión Génica , Hormonas/metabolismoRESUMEN
A LC-MS/MS simultaneous analytical method for screening 191 pesticide residues in limes had been developed and validated. Pesticides were extracted with acetonitrile from samples. Then mixed salts, which were anhydrous magnesium sulfate for dehydration, sodium carbonate for adjusting pH, and sodium chloride for salting out, were added to the sample. After centrifugation, supernatant was transferred to a tube. The sample solution was cleaned up using solid phase extraction (SPE) with C18/GC/PSA for the determination by LC-MS/MS. The developed method was improved the recovery rate of thiabendazole, which had a low recovery rate by the conventional method. Validation study, which was following the guidelines of the Ministry of Health, Labor and Welfare, were carried out at 0.01 and 0.1 µg g-1 to evaluate the method. The results of 175 pesticides out of 191 were with satisfactory. A total of 19 imported lime samples sold in Tokyo was analyzed to evaluate the method, then 18 samples contained pesticide residues below MRLs. The developed method is applicable for detection of pesticide residues in lime.
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Citrus aurantiifolia , Residuos de Plaguicidas , Cromatografía Liquida , Residuos de Plaguicidas/análisis , Espectrometría de Masas en Tándem , TokioRESUMEN
Narcolepsy is a sleep disorder caused by the loss of orexin (hypocretin)-producing neurons and marked by excessive daytime sleepiness and a sudden weakening of muscle tone, or cataplexy, often triggered by strong emotions. In a mouse model for narcolepsy, we previously demonstrated that serotonin neurons of the dorsal raphe nucleus (DRN) mediate the suppression of cataplexy-like episodes (CLEs) by orexin neurons. Using an optogenetic tool, in this paper we show that the acute activation of DRN serotonin neuron terminals in the amygdala, but not in nuclei involved in regulating rapid eye-movement sleep and atonia, suppressed CLEs. Not only did stimulating serotonin nerve terminals reduce amygdala activity, but the chemogenetic inhibition of the amygdala using designer receptors exclusively activated by designer drugs also drastically decreased CLEs, whereas chemogenetic activation increased them. Moreover, the optogenetic inhibition of serotonin nerve terminals in the amygdala blocked the anticataplectic effects of orexin signaling in DRN serotonin neurons. Taken together, the results suggest that DRN serotonin neurons, as a downstream target of orexin neurons, inhibit cataplexy by reducing the activity of amygdala as a center for emotional processing.
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Amígdala del Cerebelo , Catalepsia , Núcleo Dorsal del Rafe , Neuronas Serotoninérgicas/metabolismo , Transducción de Señal , Amígdala del Cerebelo/metabolismo , Amígdala del Cerebelo/patología , Amígdala del Cerebelo/fisiopatología , Animales , Catalepsia/genética , Catalepsia/metabolismo , Catalepsia/patología , Catalepsia/fisiopatología , Núcleo Dorsal del Rafe/metabolismo , Núcleo Dorsal del Rafe/patología , Núcleo Dorsal del Rafe/fisiopatología , Movimientos Oculares , Masculino , Ratones , Ratones Noqueados , Neuronas Serotoninérgicas/patología , Serotonina/metabolismoRESUMEN
The hypothalamus plays an important role in the regulation of sleep/wakefulness states. While the ventrolateral preoptic nucleus (VLPO) plays a critical role in the initiation and maintenance of sleep, the lateral posterior part of the hypothalamus contains neuronal populations implicated in maintenance of arousal, including orexin-producing neurons (orexin neurons) in the lateral hypothalamic area (LHA) and histaminergic neurons in the tuberomammillary nucleus (TMN). During a search for neurons that make direct synaptic contact with histidine decarboxylase-positive (HDC+), histaminergic neurons (HDC neurons) in the TMN and orexin neurons in the LHA of male mice, we found that these arousal-related neurons are heavily innervated by GABAergic neurons in the preoptic area including the VLPO. We further characterized GABAergic neurons electrophysiologically in the VLPO (GABAVLPO neurons) that make direct synaptic contact with these hypothalamic arousal-related neurons. These neurons (GABAVLPOâHDC or GABAVLPOâorexin neurons) were both potently inhibited by noradrenaline and serotonin, showing typical electrophysiological characteristics of sleep-promoting neurons in the VLPO. This work provides direct evidence of monosynaptic connectivity between GABAVLPO neurons and hypothalamic arousal neurons and identifies the effects of monoamines on these neuronal pathways.SIGNIFICANCE STATEMENT Rabies-virus-mediated tracing of input neurons of two hypothalamic arousal-related neuron populations, histaminergic and orexinergic neurons, showed that they receive similar distributions of input neurons in a variety of brain areas, with rich innervation by GABAergic neurons in the preoptic area, including the ventrolateral preoptic area (VLPO), a region known to play an important role in the initiation and maintenance of sleep. Electrophysiological experiments found that GABAergic neurons in the VLPO (GABAVLPO neurons) that make direct input to orexin or histaminergic neurons are potently inhibited by noradrenaline and serotonin, suggesting that these monoamines disinhibit histamine and orexin neurons. This work demonstrated functional and structural interactions between GABAVLPO neurons and hypothalamic arousal-related neurons.
Asunto(s)
Nivel de Alerta/fisiología , Neuronas GABAérgicas/fisiología , Área Hipotalámica Lateral/fisiología , Área Preóptica/fisiología , Sueño/fisiología , Animales , Neuronas GABAérgicas/citología , Área Hipotalámica Lateral/citología , Masculino , Ratones , Ratones Transgénicos , Vías Nerviosas/citología , Vías Nerviosas/metabolismo , Norepinefrina/metabolismo , Área Preóptica/citología , Serotonina/metabolismoRESUMEN
Sleep-wake behavior is controlled by a wide range of neuronal populations in the mammalian brain. Although the ventral midbrain/pons (VMP) area is suggested to participate in sleep-wake regulation, the neuronal mechanisms have remained unclear. Here, we found that nonspecific cell ablation or selective ablation of GABAergic neurons by expressing diphtheria toxin fragment A in the VMP in male mice induced a large increase in wakefulness that lasted at least 4 weeks. In contrast, selective ablation of dopaminergic neurons in the VMP had little effect on wakefulness. Chemogenetic inhibition of VMP GABAergic neurons also markedly increased wakefulness. The wake-promoting effect of the VMP GABAergic neuron ablation or inhibition was attenuated to varying degrees by the administration of dopamine D1 or D2/3 receptor antagonists and abolished by the administration of both antagonists together. In contrast, chemogenetic activation of VMP GABAergic neurons very strongly increased slow-wave sleep and reduced wakefulness. These findings suggest that VMP GABAergic neurons regulate dopaminergic actions in the sleep-wake behavior of mice.SIGNIFICANCE STATEMENT Current understanding of the neuronal mechanisms and populations that regulate sleep-wake behavior is incomplete. Here, we identified a GABAergic ventral midbrain/pons area that is necessary for controlling the daily amount of sleep and wakefulness in mice. We also found that these inhibitory neurons control wakefulness by suppressing dopaminergic systems. Surprisingly, activation of these neurons strongly induced slow-wave sleep while suppressing wakefulness. Our study reveals a new brain mechanism critical for sleep-wake regulation.
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Neuronas GABAérgicas/fisiología , Mesencéfalo/fisiología , Puente/fisiología , Sueño/fisiología , Vigilia/fisiología , Animales , Antagonistas de Dopamina/farmacología , Electroencefalografía/métodos , Neuronas GABAérgicas/efectos de los fármacos , Masculino , Mesencéfalo/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Puente/efectos de los fármacos , Sueño/efectos de los fármacos , Vigilia/efectos de los fármacosRESUMEN
We measured the residual amounts of chlorantraniliprole in various vegetables and fruits. Sample solutions were prepared according to our routine procedure based on the QuEChERS method and analyzed by LC-MS/MS. Performance characteristics were evaluated for 8 kinds of food samples by means of recovery tests of 5 replicates at the concentration of 10 ng/g. Recoveries and RSDs (ï¼ ) ranged from 50.2 to 93.4ï¼ and from 2.1 to 9.7ï¼ , respectively. Application of this method to survey 207 vegetables and 163 fruits gave detection rates of 8.2 and 1.2ï¼ , respectively. In vegetables, detection rates were high in okra (4 out of 10 samples), paprika (4 out of 23 samples) and tomato (2 out of 6 samples), and leaf vegetables such as lettuce, mizuna, spinach and wrinkled greens also contained high concentrations of chlorantraniliprole. The highest residual concentration was 571 ng/g in mizuna. The samples containing chlorantraniliprole seemed to be mainly from Asian countries, including samples of domestic Japanese origin. However, none of them contained more than the MRL, which suggests that the use of chlorantraniliprole has been properly controlled.
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Análisis de los Alimentos/métodos , Contaminación de Alimentos/análisis , Frutas/química , Residuos de Plaguicidas/análisis , Verduras/química , ortoaminobenzoatos/análisis , Cromatografía Liquida , Espectrometría de Masas en TándemRESUMEN
The noradrenergic (NA) projections arising from the locus ceruleus (LC) to the amygdala and bed nucleus of the stria terminalis have been implicated in the formation of emotional memory. Since NA neurons in the LC (LC-NA neurons) abundantly express orexin receptor-1 (OX1R) and receive prominent innervation by orexin-producing neurons, we hypothesized that an OX1R-mediated pathway is involved in the physiological fear learning process via regulation of LC-NA neurons. To evaluate this hypothesis, we examined the phenotype of Ox1r(-/-) mice in the classic cued and contextual fear-conditioning test. We found that Ox1r(-/-) mice showed impaired freezing responses in both cued and contextual fear-conditioning paradigms. In contrast, Ox2r(-/-) mice showed normal freezing behavior in the cued fear-conditioning test, while they exhibited shorter freezing time in the contextual fear-conditioning test. Double immunolabeling of Fos and tyrosine hydroxylase showed that double-positive LC-NA neurons after test sessions of both cued and contextual stimuli were significantly fewer in Ox1r(-/-) mice. AAV-mediated expression of OX1R in LC-NA neurons in Ox1r(-/-) mice restored the freezing behavior to the auditory cue to a comparable level to that in wild-type mice in the test session. Decreased freezing time during the contextual fear test was not affected by restoring OX1R expression in LC-NA neurons. These observations support the hypothesis that the orexin system modulates the formation and expression of fear memory via OX1R in multiple pathways. Especially, OX1R in LC-NA neurons plays an important role in cue-dependent fear memory formation and/or retrieval.
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Señales (Psicología) , Miedo , Locus Coeruleus/fisiología , Memoria , Receptores de Neuropéptido/metabolismo , Neuronas Adrenérgicas/metabolismo , Neuronas Adrenérgicas/fisiología , Animales , Condicionamiento Clásico , Reacción Cataléptica de Congelación , Locus Coeruleus/citología , Locus Coeruleus/metabolismo , Ratones , Ratones Noqueados , Receptores de Orexina , Tiempo de Reacción , Receptores de Neuropéptido/genéticaRESUMEN
The relationship between mental disorders and sleep remains unclear. Two new studies show that the lateral habenula, a brain region associated with value-guided behavior, controls REM sleep and promotes emotional stability but also contributes to REM sleep disinhibition in depression.
Asunto(s)
Depresión , Sueño REM , Sueño REM/fisiología , Humanos , Depresión/fisiopatología , Animales , Habénula/fisiología , Habénula/fisiopatología , Salud MentalRESUMEN
Animals have a sleep cycle that involves the repetitive occurrence of non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. In a previous study, we discovered that a transient increase in dopamine (DA) levels in the basolateral amygdala (BLA) during NREM sleep terminates NREM sleep and initiates REM sleep by acting on Drd2-positive neurons (Hasegawa et al., 2022). In this study, we identified the neurons activated by the transient increase of DA in the BLA and found that chemogenetic excitation of these neurons increased REM sleep. Additionally, we demonstrated that acute inhibition of serotonin (5HT) in the BLA elicited a transient increase in DA in the BLA, which triggered REM sleep.
Asunto(s)
Complejo Nuclear Basolateral , Sueño REM , Ratones , Animales , Sueño REM/fisiología , Dopamina , Serotonina , Sueño/fisiologíaRESUMEN
Orexin-A and orexin-B are hypothalamic neuropeptides that play critical roles in the maintenance of wakefulness. Intracerebroventricular (ICV) administration of orexin-A has been shown to promote wakefulness and suppress both rapid eye movement (REM) sleep and non-REM (NREM) sleep through the orexin receptor-1 (OX(1)R) and orexin receptor-2 (OX(2)R). Here, we elucidated the differential roles of orexin receptors in the regulation of sleep and wakefulness by comparing the effects of ICV orexin-A administration in wild-type, OX(1)R(-/-), and OX(2)R(-/-) mice. The effects of orexin-A on wakefulness and NREM sleep were significantly attenuated in both knock-out mice as compared with wild-type mice, with substantially larger attenuation in OX(2)R(-/-) mice than in OX(1)R(-/-) mice. These results suggest that although the OX(2)R-mediated pathway has a pivotal role in the promotion of wakefulness, OX(1)R also plays additional roles in promoting arousal. In contrast, suppression of REM sleep by orexin-A administration was slightly and similarly attenuated in both OX(1)R(-/-) and OX(2)R(-/-) mice, suggesting a comparable contribution of the two receptors to REM sleep suppression. Histological studies demonstrated differential distributions of each receptor subtype in distinct neuronal populations with specific neurotransmitter identities in brainstem cholinergic/monoaminergic neurons. In the laterodorsal tegmental and pedunculopontine tegmental nuclei especially, cholinergic neurons exclusively expressed OX(1)R mRNA, but OX(2)R mRNA was expressed mainly in GABAergic putative interneurons. Thus, each orexin receptor subtype plays differential roles in gating NREM and REM sleep through distinct neuronal pathways.
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Antígenos de Superficie/fisiología , Encéfalo/fisiología , Receptores de Superficie Celular/fisiología , Receptores Acoplados a Proteínas G/fisiología , Receptores de Neuropéptido/fisiología , Fases del Sueño/fisiología , Vigilia/fisiología , Análisis de Varianza , Animales , Antígenos de Superficie/genética , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Relación Dosis-Respuesta a Droga , Electroencefalografía , Electromiografía , Glutamato Descarboxilasa/genética , Glutamato Descarboxilasa/metabolismo , Inyecciones Intraventriculares/métodos , Péptidos y Proteínas de Señalización Intracelular/farmacología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Modelos Neurológicos , Neuropéptidos/farmacología , Neurotransmisores/farmacología , Oligodesoxirribonucleótidos Antisentido/farmacología , Receptores de Orexina , Orexinas , Receptores de Superficie Celular/deficiencia , Receptores de Superficie Celular/genética , Receptores Acoplados a Proteínas G/deficiencia , Receptores Acoplados a Proteínas G/genética , Receptores de Neuropéptido/deficiencia , Receptores de Neuropéptido/genética , Fases del Sueño/efectos de los fármacos , Fases del Sueño/genética , Proteínas de Transporte Vesicular de Acetilcolina/genética , Proteínas de Transporte Vesicular de Acetilcolina/metabolismo , Proteínas de Transporte Vesicular de Monoaminas/genética , Proteínas de Transporte Vesicular de Monoaminas/metabolismo , Vigilia/efectos de los fármacos , Vigilia/genéticaRESUMEN
The sleep cycle alternates between REM and NREM sleep, but the mechanisms by which this cycle is generated are totally unknown. We found that a periodic transient increase of the dopamine level in the amygdala during NREM sleep terminates NREM sleep and initiates REM sleep. This mechanism also plays a role in cataplectic attack, which is a pathological intrusion of REM sleep into wakefulness in narcoleptics.
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Complejo Nuclear Basolateral , Sueño REM , Ratones , Animales , Dopamina , Vigilia , Sueño , ElectroencefalografíaRESUMEN
The sleep cycle is characterized by alternating non-rapid eye movement (NREM) and rapid eye movement (REM) sleeps. The mechanisms by which this cycle is generated are incompletely understood. We found that a transient increase of dopamine (DA) in the basolateral amygdala (BLA) during NREM sleep terminates NREM sleep and initiates REM sleep. DA acts on dopamine receptor D2 (Drd2)-expressing neurons in the BLA to induce the NREM-to-REM transition. This mechanism also plays a role in cataplectic attacks-a pathological intrusion of REM sleep into wakefulness-in narcoleptics. These results show a critical role of DA signaling in the BLA in initiating REM sleep and provide a neuronal basis for sleep cycle generation.
Asunto(s)
Complejo Nuclear Basolateral/metabolismo , Dopamina/metabolismo , Sueño REM/fisiología , Animales , Cataplejía/fisiopatología , Masculino , Ratones , Ratones Endogámicos C57BL , Neuronas/metabolismo , Receptores de Dopamina D2/metabolismo , Transducción de Señal , Sueño/fisiología , VigiliaRESUMEN
Structurally diverse small compounds are utilized to obtain hit compounds that have suitable pharmacophores in appropriate three-dimensional conformations for the target drug receptors. We have focused on the 1,3,5-trioxazatriquinane skeleton, which has a rigid bowl-like structure enabling the diverse orientation of side chain units, leading to a novel small-scale focused library based on the skeleton. In the library screening for the orexin receptor, some of the compounds showed orexin receptor antagonistic activity with a high hit rate of 7%. By optimizing the hit compounds, we discovered a potent dual orexin receptor antagonist, 38b, and a selective orexin 1 receptor antagonist, 41b carrying the same plane structure. Both compounds showed reasonable brain permeability and beneficial effects when administered intraperitoneally to wild-type mice. Docking simulations of their eutomers, (-)-38b and (+)-41b, with orexin receptors suggested that the interaction between the 1,3,5-trioxazatriquinane core structure and the hydrophobic subpocket in orexin receptors enables a U-shape structure, which causes tight van der Waals interactions with the receptors similar to SB-334867, a selective orexin 1 receptor antagonist. These results indicate that the library approach utilizing the 1,3,5-trioxazatriquinanes bearing multiple effective residues (TriMERs) might be useful for the hit discovery process targeting not only opioid and orexin receptors but other G-protein coupled receptors.
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Antagonistas de los Receptores de Orexina , Animales , Compuestos Heterocíclicos de 4 o más Anillos , Ratones , Antagonistas de los Receptores de Orexina/química , Antagonistas de los Receptores de Orexina/farmacología , Receptores de Orexina , Orexinas , Relación Estructura-ActividadRESUMEN
The dorsal raphe nucleus (DRN) is known to control aggressive behavior in mice. Here, we found that glutamatergic projections from the lateral habenula (LHb) to the DRN were activated in male mice that experienced pre-exposure to a rival male mouse ("social instigation") resulting in heightened intermale aggression. Both chemogenetic and optogenetic suppression of the LHb-DRN projection blocked heightened aggression after social instigation in male mice. In contrast, inhibition of this pathway did not affect basal levels of aggressive behavior, suggesting that the activity of the LHb-DRN projection is not necessary for the expression of species-typical aggressive behavior, but required for the increase of aggressive behavior resulting from social instigation. Anatomical analysis showed that LHb neurons synapse on non-serotonergic DRN neurons that project to the ventral tegmental area (VTA), and optogenetic activation of the DRN-VTA projection increased aggressive behaviors. Our results demonstrate that the LHb glutamatergic inputs to the DRN promote aggressive arousal induced by social instigation, which contributes to aggressive behavior by activating VTA-projecting non-serotonergic DRN neurons as one of its potential targets.