Orexins (or hypocretins) are hypothalamic neuropeptides with a multitude of physiological functions. They occur in two known forms, namely, orexin A and orexin B with a common precursor, preproorexin. The orexin recep...Orexins (or hypocretins) are hypothalamic neuropeptides with a multitude of physiological functions. They occur in two known forms, namely, orexin A and orexin B with a common precursor, preproorexin. The orexin receptors (orexin 1R and orexin 2R) belong to the Family of G-protein coupled receptors. The primary function of the orexin system,i.e. the orexins, their receptors and associated neuronal circuitries, perhaps is to increase spontaneous physical activity and food intake, thereby promoting an increase in energy expenditure. Reports suggest that orexins may be the key brain components to mediate the mechanism of obesity resistance. Recent research also has thrown lights upon a significant role of orexins, especially orexin A, in regulation of male reproductive functions owing to their receptor expressions in vital testicular cells, such as Leydig cells, Sertoli cells as well as spermatozoa at different developmental stages, even in the epididymis and penis. Moreover, orexins have been reported to greatly influence gonadotropin-releasing hormone neurons and their secretions to regulate reproductive functionsvia modulation of the hypothalamic-pituitary-gonadal axis. Evidence thus implicates participation of orexins in steroidogenesis, spermatogenesis, transportation and maturation of sperm as well as in the control of penile function. However, further research is required in this direction to elucidate the mechanisms by which orexins play a role in different testicular functions and effect of orexins on semen quality.展开更多
Hypothalamic neuropeptides named hypocretin/orexins which were identified in 1998 regulate critical functions such as wakefulness in the central nervous system.These past 20 years had revealed that orexins/receptors s...Hypothalamic neuropeptides named hypocretin/orexins which were identified in 1998 regulate critical functions such as wakefulness in the central nervous system.These past 20 years had revealed that orexins/receptors system was also present in the peripheral nervous system where they participated to the regulation of multiple functions including blood pressure regulation,intestinal motility,hormone secretion,lipolyze and reproduction functions.Associated to these peripheral functions,it was found that orexins and their receptors were involved in various diseases such as acute/chronic inflammation,metabolic syndrome and cancers.The present review suggests that orexins or the orexin neural circuitry represent potential therapeutic targets for the treatment of multiple pathologies related to inflammation including intestinal bowel disease,multiple sclerosis and septic shock,obesity and digestive cancers.展开更多
Alzheimer's disease(AD) is a growing health problem. It has enormous public health impact. Sleep problems show an early component of this disease. Hypocretin hasa major function in sleep-wake cycle. The total numb...Alzheimer's disease(AD) is a growing health problem. It has enormous public health impact. Sleep problems show an early component of this disease. Hypocretin hasa major function in sleep-wake cycle. The total number of hypocretin neurons in the normal humans ranges from 51000-83000, located exclusively in the hypothalamus. Deficiency in hypocretins neurotransmission results in narcolepsy, Parkinson's disease, and other neurological and psychological disorders. Cerebrospinal fluid(CSF) hypocretin levels were directly related with t-tau protein amount in AD. Increased hypocretin CSF in AD suggest that hypocretin is involved in the mechanism of AD pathology.展开更多
该文采用RT-PCR和cDNA末端快速扩增技术(rapid-amplification of cDNA ends,RACE)的方法,从尼罗罗非鱼(Oreochromis niloticus)下丘脑总RNA中获得了尼罗罗非鱼Orexin前体基因的cDNA全长序列。该cDNA全长648bp,其中开放阅读框的长423bp,...该文采用RT-PCR和cDNA末端快速扩增技术(rapid-amplification of cDNA ends,RACE)的方法,从尼罗罗非鱼(Oreochromis niloticus)下丘脑总RNA中获得了尼罗罗非鱼Orexin前体基因的cDNA全长序列。该cDNA全长648bp,其中开放阅读框的长423bp,编码Orexin前体蛋白为140个氨基酸,包括37个氨基酸的信号肽、43个氨基酸的Orexin-A、28个氨基酸的Orexin-B和末尾32个氨基酸组成的功能不详的多肽。采用Real-time PCR技术对尼罗罗非鱼Orexin前体基因的组织表达模式以及在摄食前后、饥饿和再投喂状态下的表达量变化进行了研究。结果显示,在脑部和外周等18个组织中都检测到了Orexin前体基因的表达,其中在下丘脑中表达量最高;在摄食前后,尼罗罗非鱼Orexin前体基因的表达量显著低于在摄食状态中;饥饿2、4、6和8d后,Orexin前体基因在下丘脑中的表达量与正常投喂组相比均显著升高,饥饿4d再投喂后,表达量又恢复至正常水平。这些结果表明,Orexin在尼罗罗非鱼摄食中可能有着重要的调节作用。展开更多
文摘Orexins (or hypocretins) are hypothalamic neuropeptides with a multitude of physiological functions. They occur in two known forms, namely, orexin A and orexin B with a common precursor, preproorexin. The orexin receptors (orexin 1R and orexin 2R) belong to the Family of G-protein coupled receptors. The primary function of the orexin system,i.e. the orexins, their receptors and associated neuronal circuitries, perhaps is to increase spontaneous physical activity and food intake, thereby promoting an increase in energy expenditure. Reports suggest that orexins may be the key brain components to mediate the mechanism of obesity resistance. Recent research also has thrown lights upon a significant role of orexins, especially orexin A, in regulation of male reproductive functions owing to their receptor expressions in vital testicular cells, such as Leydig cells, Sertoli cells as well as spermatozoa at different developmental stages, even in the epididymis and penis. Moreover, orexins have been reported to greatly influence gonadotropin-releasing hormone neurons and their secretions to regulate reproductive functionsvia modulation of the hypothalamic-pituitary-gonadal axis. Evidence thus implicates participation of orexins in steroidogenesis, spermatogenesis, transportation and maturation of sperm as well as in the control of penile function. However, further research is required in this direction to elucidate the mechanisms by which orexins play a role in different testicular functions and effect of orexins on semen quality.
基金INSERM U1149/The Inflammation Research Center,Inserm Transfert,The Institut National du Cancer,No.2013-213Ligue Nationale Contre le Cancer,No.R16020HH,GB/MA/CD/EP-12062and AgroParisTech(INRAE and UniversitéParis-Saclay).
文摘Hypothalamic neuropeptides named hypocretin/orexins which were identified in 1998 regulate critical functions such as wakefulness in the central nervous system.These past 20 years had revealed that orexins/receptors system was also present in the peripheral nervous system where they participated to the regulation of multiple functions including blood pressure regulation,intestinal motility,hormone secretion,lipolyze and reproduction functions.Associated to these peripheral functions,it was found that orexins and their receptors were involved in various diseases such as acute/chronic inflammation,metabolic syndrome and cancers.The present review suggests that orexins or the orexin neural circuitry represent potential therapeutic targets for the treatment of multiple pathologies related to inflammation including intestinal bowel disease,multiple sclerosis and septic shock,obesity and digestive cancers.
文摘Alzheimer's disease(AD) is a growing health problem. It has enormous public health impact. Sleep problems show an early component of this disease. Hypocretin hasa major function in sleep-wake cycle. The total number of hypocretin neurons in the normal humans ranges from 51000-83000, located exclusively in the hypothalamus. Deficiency in hypocretins neurotransmission results in narcolepsy, Parkinson's disease, and other neurological and psychological disorders. Cerebrospinal fluid(CSF) hypocretin levels were directly related with t-tau protein amount in AD. Increased hypocretin CSF in AD suggest that hypocretin is involved in the mechanism of AD pathology.
