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Abstract Background Several randomized clinical trials (RCTs) have shown that dual orexin receptor antagonists (DORAs) are effective in the treatment of chronic insomnia. However, the superiority of one particular DORA over the others remains unclear. Objective To perform a network meta-analysis to evaluate the efficacy of different DORAs in patients with chronic insomnia. Methods The Medline, Embase, and Cochrane Central databases were searched for RCTs that compared DORA with placebo in patients ≥ 18 years of age with a diagnosis of insomnia disorder. We pooled outcomes for wake time after sleep onset (WASO), latency to persistent sleep (LPS), total sleep time (TST), and adverse events (AEs). Results We included 10 RCTs with 7,806 patients, 4,849 of whom received DORAs as the intervention. Overall, we found that DORAs were associated with the improvement of all analyzed efficacy outcomes. Concerning TST, an apparent dose-dependent pattern was noticed, with higherdoses relating to a longerTST. Lemborexant 10mg provided the largest reduction in WASO (at month 1) in minutes (standardized mean difference [SMD] = −25.40; 95% confidence interval [95%CI] = −40.02- −10.78), followed by suvorexant 20/15mg (SMD = −25.29; 95%CI = −36.42- −14.15), which also appeared to provide the largest decrease in long-term WASO (SMD = −23.70; 95%CI = −35.89- −11.51). The most frequent AEs were somnolence, nasopharyngitis, and headache, with rates of up to 14.8%. Conclusion Our results suggest that DORAs are associated with greater efficacy when compared with placebo in the treatment of insomnia, a complex 24-hour sleep disorder. Additionally, dosing might play an important role in the management of chronic insomnia.
Resumo Antecedentes Inúmeros ensaios clínicos randomizados (ECRs) têm demonstrado que os antagonistas duais do receptor de orexina (dual orexin receptor antagonists, DORAs, em inglês) são eficazes no tratamento da insônia. Contudo, restam dúvidas quanto à superioridade de um DORA com relação aos outros. Objetivo Realizar uma meta-análise em rede para avaliar a eficácia de diferentes DORAs em pacientes com insônia. Métodos Foram feitas buscas nas bases de dados Medline, Embase e Cochrane Central por ECRs que comparassem DORAs e placebo em pacientes ≥ 18 anos de idade com diagnóstico de insônia. Os seguintes desfechos foram selecionados: tempo desperto após o início do sono (wake time after sleep onset, WASO, em inglês), latência para o sono persistente (latency to persistent sleep, LPS, em inglês), tempo total de sono (total sleep time, TST, em inglês), e efeitos adversos (EAs). Resultados Incluímos 10 ensaios clínicos com 7,806 pacientes, 4,849 dos quais receberam DORAs como intervenção. Os DORAs foram associados à melhoria de todos os desfechos de eficácia analisados. Em relação ao TST, um aparente padrão de dependência da dose foi identificado, com doses maiores se associando a um maior TST. Lemborexant 10 mg proporcionou a maior redução em WASO (no primeiro mês) em minutos (diferença padronizada das médias [standardized mean difference, [SMD], em inglês) = −25.40; intervalo de confiança de 95% [IC95%] = −40.02- −10.78), seguido de suvorexant 20/15mg (SMD = −25.29; IC95% = −36.42- −14.15), o qual também proporcionou a maior diminuição em WASO no longo prazo (SMD = −23.70; IC95% = −35.89- −11.51). Os EAs mais frequentes foram sonolência, nasofaringite e cefaleia, com taxas de até 14.8%. Conclusão Nossos resultados sugerem que os DORAs estão associados a uma maior eficácia quando comparados com placebo no tratamento da insónia, um complexo transtorno do sono de 24 horas. Além disso, a dosagem pode desempenhar um papel importante no manejo da insónia crônica.
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In past two decades, understanding of the role of the orexin system in regulating sleep and wakefulness has increased rapidly. Lemborexant, as a dual orexin receptor antagonist, has been approved in some countries for the treatment of insomnia disorders. Existing studies have shown that its safety and tolerability are significantly superior to traditional hypnotic drugs, and it will be new option for treating insomnia disorders. This article reviews the pharmacology, clinical efficacy and safety of lemborexant.
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Objective:to explore the mechanism of modified Tianwang Buxindan in improving abnormal glucose and lipid metabolism in mice with chronic sleep deprivation from the signal pathway of orexin A/ orexin receptor 1（OX1R）. Method:The 50 6-week-old male C57BL/6 mice were randomly divided into blank group ， model group ， estazolam group and Tianwang Buxindan low and high dose groups ，for ten mice of each group. Except the blank group， rats were deprived of sleep for 8 weeks by the method of multi-platform water environment. In the last 4 weeks， Tianwang Buxindan （8.5，17 g·kg-1）and estazolam solution（9.1 mg·kg-1）were given to the stomach， and the blank group and the model group were fed with pure water of the same volume. The food intake and body weight of mice were measured twice a week， on the 49th day， blood samples were collected from the tail vein for glucose tolerance test （GTT），on the 52nd day for insulin tolerance test（ITT）， was used to detect the expression of total cholesterol （TCH）， triglyceride（TG）and free fatty acid（FFA）in serum， and enzyme-linked immunosorbent assay（ELISA）was used to detect the expression of orexin A in serum and hypothalamus. Real-time fluorescence quantitative polymerase chain reaction（Real-time PCR）and Western blot were used to detect the mRNA and protein expression of OX1R in hypothalamus. Result:After administration， the food intake of mice in each group was different， compared with the blank group， the body weight of model group was significantly reduced（P<0.05）， the glucose tolerance was significantly abnormal， and the TCH， TG， FFA values were significantly increased（P<0.01）. The expression of orexin A in serum and hypothalamus increased significantly（P<0.01）， and the mRNA and protein expression levels of OX1R in hypothalamus increased significantly（P<0.01）. Compared with the model group， the body weight of each group of Tianwang Buxindan was significantly increased（P<0.05）， with better glucose tolerance and insulin sensitivity， TCH， TG， FFA values were significantly reduced（P<0.05，P<0.01）， accompanied by serum and the expression of orexin A in the hypothalamus was significantly decreased（P<0.05，P<0.01）， the mRNA and protein expression levels of OX1R were significantly decreased（P<0.05，P<0.01）. Conclusion:Tianwang Buxindan can protect mice from abnormal glucose and lipid metabolism induced by chronic sleep deprivation， and its mechanism may be related to the down-regulation of orexin A/OX1R signal expression.
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Objective: To observe the mRNA levels of Orexin and its receptors in the hypothalamus of ovariectomized osteoporosis rats, in order to explore the pathogenesis of postmenopausal osteoporosis(PMOP) and the mechanism Zuoguiwan. Method: An osteoporosis model induced by ovariectomy was established in rats. Totally 32 female Sprague-Dawley (SD) rats were randomly divided into sham-operated group, ovariectomized model group, 17β-estradiol treated positive group, and Zuoguiwan group, with 8 rates in each group. After 12 weeks of intragastric administration, the bone mineral density (BMD) and trabecular microstructural changes of femur were detected by micro-CT (μ-CT), and the morphological changes of bone tissue were observed by hematoxylin-eosin staining (HE) staining. The markers of bone turnover in serum osteocalcin (OCN), N-terminal propeptide of type Ⅰ procollagen (PINP), tartrate-resistant acid phosphatase (TRAP) were measured using enzyme-linked immunosorbent assay (ELISA). The mRNA expressions of orexin, orexin receptor 1 (OX1R) and orexin receptor 2 (OX2R) were measured by Real-time PCR. Result: Compared with sham-operated group, the μ-CT showed that BMD, bone volume fraction(BV/TV), trabecular thickness(Tb. Th)and trabecular number(Tb. N)in ovariectomized model group were significantly decreased (PPN-terminal propeptide of type Ⅰ procollagen (PINP) levels decreased, whereas tartrate-resistant acid phosphatase (TRAP) content increased (PPPPPPPPPPConclusion: Decreased mRNA levels of Orexin and its receptors in the hypothalamus may be one of the mechanisms of PMOP. Zuoguiwan may correct the imbalance of bone metabolism, improve the trabecular microstructure and improve bone by up-regulating the mRNA expressions of Orexin and its receptors in the hypothalamus, density, so as to show a therapeutic effect on PMOP.
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BACKGROUND: The trigeminal nucleus caudalis (Vc) is a primary central site for trigeminal transmitting. Noxious stimulation of the trigeminal nociceptors alters the central synaptic releases and neural expression of some inflammatory and trophic agents. Orexin-A and the orexin 1 receptor (OX1R) are expressed in pain pathways including trigeminal pain transmission. However, the the mechanism(s) underling orexin-A effects on trigeminal pain modulation have not been fully clarified. METHODS: Trigeminal pain was induced by subcutaneous injection of capsaicin in the upper lip in rats. The effect of trigeminal pain on cyclooxygenase-2 (COX-2) and brain-derived neurotrophic factor (BDNF) expression in the Vc of animals was determined by immunofluorescence. Subsequently, OX1R agonist (orexin-A) and antagonist (SB-334867-A) was administrated in the Vc to investigate the possible roles of the Vc OX1R on changes in COX-2 and BDNF levels following pain induction. RESULTS: The data indicated an increase in COX-2 and decrease in BDNF immuno-reactivity in the Vc of capsaicin, and capsaicin- pretreated with SB-334867-A (80 nM), groups of rat. However, the effect of capsaicin on COX-2 and BDNF expressions was reversed by a Vc microinjection of orexin-A (100 pM). CONCLUSIONS: Overall, the present data reveals that orexin-A can attenuate capsaicin-induced trigeminal pain through the modulation of pain effects on COX-2 and BDNF expressions in the Vc of rats.
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Animals , Rats , Brain-Derived Neurotrophic Factor , Capsaicin , Cyclooxygenase 2 , Facial Pain , Fluorescent Antibody Technique , Injections, Subcutaneous , Lip , Microinjections , Nociceptors , Orexin Receptor Antagonists , Orexins , Pain Measurement , Pain Perception , Trigeminal Caudal Nucleus , Trigeminal Neuralgia , Trigeminal NucleiABSTRACT
The orexin system was discovered in 1998 with two G-protein coupled receptors (GPCRs):orexin-1 (OX1R) and orexin-2 (OX2R) receptors that bind the neuropeptides orexin-A (OX-A) and orexin-B (OX-B). The causal link between the orexin system and obesity, anxiety, and sleep/wake disorders as a potential therapeutic target has drawn much attention in the field of pharmaceuticals. The developments of dual antagonism of the receptors by small molecules are clinically efficacious in the treatment of insomnia, where the most advanced molecule suvorexant has been approved by FDA in August, 2014. The small molecule orexin receptor antagonists (ORA) between January 2010 and August 2017 are summarized in this review and we focus on their chemical structures, mechanism and human clinical trials.
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OBJECTIVE: Suvorexant is a novel hypnotic drug that does not interact with the conventional γ-aminobutyric acid (GABA)-A receptor. We investigated the method by which suvorexant was introduced in insomnia patients who were taking benzodiazepine receptor agonists (BzRA). METHODS: This was a retrospective study. We extracted clinical data for patients who were prescribed suvorexant and were already using BzRA. The patients were assigned to two groups, the switching and add-on groups. We assessed the suvorexant discontinuation rate at one month after the prescription of the drug. RESULTS: One hundred and nineteen patients were assigned to the switching group, and 109 were assigned to the add-on group. The add-on group exhibited a significantly higher all-cause discontinuation rate than the switching group (odds ratio, 2.7; 95% confidence interval, 1.5 to 5.0; adjusted p < 0.001). Intolerability was a significantly stronger risk factor for suvorexant discontinuation in the add-on group (22.0% vs. 7.6%, p < 0.002), and the most common adverse effect was oversedation. CONCLUSION: Our results show that the add-on of suvorexant increases the frequency of oversedation compared with switching in insomnia patients that are taking BzRA. However, this was only a preliminary retrospective study, and further studies will be required to confirm our findings.
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Humans , Benzodiazepines , Methods , Orexin Receptor Antagonists , Prescriptions , Receptors, GABA-A , Retrospective Studies , Risk Factors , Sleep Initiation and Maintenance DisordersABSTRACT
Objective To explore the possibility of heterodimerization between orexin type 2α receptor (OX2αR) and orexin type 2β receptor (OX2βR).Methods Using confocal laser scanning microscope,enzyme linked immunosorbent assay (ELISA),fluorescence resonance energy transfer (FRET) and Bioluminescence resonance energy transfer (BRET) to study the interaction between OX2αR and OX2βR.Result Confocal laser scanning microscope and ELISA showed that OX2αR and OX2βR were both expressed in the cytoplasm.The FRET demonstrated that the signal of the experimental group (OX2αR-YFP+ OX2βR-CFP) was significantly stronger than that of control group (YFP+OX2βR-CFP).The BRET value of the experimental group (OX2αR-YFP+OX2βR-Rluc,mBRET ratio was 65± 15) was higher than that of control group (YFP+ OX2βR-Rluc/OX2αR-YFP+Rluc,mBRET ratio was 10±5) (P＜0.05).Conclusion There are heterodimerization between mOX2αR and mOX2βR.
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Objective To explore the role of Orexin in pathogenesisepilepsy and treatment of epilepsy based on the literatures published from 1998 to 2014 at home and abroad.Methods Searched the literatures from the online database including Pubmed,CNKI and Wanfang Datebases in July 2014.The words Orexin,epilepsy,Orexin receptor,epilepsy treatment were used as search terms.Analyze the effect Orexin and its receptors in the occurrence,development and treatment of epilepsy.Results 102 related literatures were retrieved and 30 were adopted into analysis.It was showed Orexin is a kind of excitatory neuropeptides and it can increase the excitability of cerebral cortex.Epilepsy can be induced bv excessive expression of Orexin.Conclusion Excessive expression of Orexin can cause epileptic seizure.Inhibiting the excessive activation of Orexin neurons is of important to control seiznres in clinical practices.
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Objective To investigate the interference effects of orexin A on cell proliferation of the insulin?secreting beta?cell line(INS?1 cells) through the orexin receptor 1(OX1R)and the AKT/PKB signaling pathway. Methods INS?1 cells were exposed to different concentrations of orexin A in vitro,and treated with OX1R antagonist(SB334867),PI3K antagonist(wortmannin),or AKT antagonist(PF?04691502). The INS?1 cell proliferation and apoptosis,insulin secretion,OX1R protein activity and AKT phosphorylation level were determined. Results Orexin A(10-10 to 10-6 mol/L)stimulated the proliferation and activation of INS?1 cells,prevented apoptpsis,and increased insulin secretion. Additionally,AKT phosphorylation was stimulated by orexin A(10-10 to 10-6 mol/L). The OX1R antagonist SB334867(10-6 mol/L),the PI3K antagonist wortmannin (10-8 mol/L)and the AKT antagonist PF?04691502(10-6 mol/L)weakened the effects of orexin A. Conclusion Orexin A activated the AKT sig?naling pathway through the mediation of orexin A?OX1R,and promoted cell proliferation in INS?1 cells.
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Objective To investigate changes in the expression of prepro-orexin and orexin receptor-1 ( OX1R) following permanent middle cerebral artery occlusion ( MCAO ) with or without preconditioning through electrical stimulation of the cerebellar fastigial nucleus (FNS). Methods Wistar rats were subjected to permanent MCAO and randomly divided into 5 groups: a sham-operated control group (PO), an FNS preconditioning + shamoperated control group (FNS-PO) , an ischemia group, an FNS preconditioning + ischemia group (FNS-PI) and a cerebellar fastigial nucleus injury + FNS preconditioning + ischemia group (FNL-FNS-PI). Each group was divided into 5 subgroups according to the time at which the animals were sacrificed after the MCAO ( 1, 3, 6, 12 and 24 h).RT-PCR was used to detect expression of OX1R mRNA, and ELISA to measure the levels of orexin-A in the hypothalamus and plasma. Results The immunoreactivity of prepro-orexin decreased significantly in the PI groups, with further decreases over time. At the 12th h after MCAO, the immunoreactivity of prepro-orexin reached a minimum.There were significant differences between the rats in the PO and FNS-PO groups. On the contrary, the immunoreactivity of OX1R increased significantly in the PI groups, with further increases continuing over time, peaking at 12 h after the MCAO. There were significant differences between the PO and FNS-PO groups. In the rats with FNS preconditioning (PI-FNS) , the decrease in prepro-orexin and the increase in OX1R were significantly inhibited compared to the PI subgroups at the 6th and 12th hour. There was no significant difference between the FNL-PIFNS group and the PI group. The expression of OX1R mRNA increased significantly in the PI group, with further increases continuing over time, peaking at 24 hours. The plasma levels of orexin-A were not significantly different among the groups, but the levels of orexin-A in the hypothalamus decreased significantly in the PI and FNL-PI-FNS groups, with further decreases continuing over time. At the 12th h after the MCAO the levels were significantly different compared with the PO and PO-FNS groups. While in the rats with FNS preconditioning (PI-FNS) , the decrease in orexin-A level was reversed and there was no significant difference compared with PO and PO-FNS groups. Conclusions The orexinergic system is altered following cerebral ischaemia. FNS preconditioning may be able to regulate these changes.
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Objective To investigate the possible role of orexin in reproduction and examine the changes in the expression of orexin and its receptors(OX1R,OX2R) in the rat hypothalamus during pregnancy,parturition and lactation. Methods The expressions of prepro-orexin(prepro-OX),orexin-A,OX1R,and OX2R in the rat hypothalamus during pregnancy,parturition,and lactation were evaluated by competitive reverse transcription-polymerase chain reaction(RT-PCR) and immunohistochemistry assay. Results Orexin-A immunoreactive(ir) neurons and the OX1R subtype in neuronal cell bodies were mainly located in the lateral hypothalamic area(LHA) as well as in the magnocellular neurons of the paraventricular and supraoptic nuclei respectively in pregnant and lactating rats.The prepro-OX and OX1R mRNA levels on the 1st day of lactation were significantly higher than that during late pregnancy and lactation.No significant changes of OX2R expression were observed during the various reproductive phases.Conclusion Orexin might be involved in regulating reproductive function in early lactation through their binding sites in hypothalamic PVN and SON.
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Objective To investigate a possible role of orexin in the regulation of estrous cycle by examining the expression of orexin and orexin receptors(OX1R,OX2R) in the rat hypothalamus during the estrous cycle. Methods The levels of prepro-orexin(prepro-OX),orexin-A,OX1R,and OX2R in the rat hypothalamus during the estrous cycle were evaluated by competitive reverse transcription-polymerase china reaction(RT-PCR) assay. Results Only expression OX1R mRNA during late proestrus was significantly higher than that at metestrus.No significant changes of prepro-OX and OX2R mRNA expression were observed during the various estrous cycle phases.Conclusion Orexin might regulate the secretion of GnRH and/or LH by binding OX1R,contributing to the occurrence of ovulation.