Orexins (hypocretins): novel hypothalamic peptides with divergent functions

2000 ◽  
Vol 78 (3) ◽  
pp. 299-305 ◽  
Author(s):  
Muhtashan S Mondal ◽  
Masamitsu Nakazato ◽  
Shigeru Matsukura
Keyword(s):  
Food Intake ◽  
Lateral Hypothalamus ◽  
Energy Homeostasis ◽  
The Novel ◽  
Important Region ◽  
Satiety Center ◽  
Feeding Center ◽  
Central Gray ◽  
Brain And Spinal Cord ◽  
The Brain

The hypothalamus is the most important region in the control of food intake and body weight. The ventromedial "satiety center" and lateral hypothalamic "feeding center" have been implicated in the regulation of feeding and energy homeostasis by various studies of brain lesions. The discovery of orexin peptides, whose neurons are localized in the lateral hypothalamus and adjacent areas, has given us new insight into the regulation of feeding. Dense fiber projections are found throughout the brain, especially in the raphe nucleus, locus coeruleus, paraventricular thalamic nucleus, arcuate nucleus, and central gray. Orexins mainly stimulate food intake, but by the virtue of wide immunoreactive projections throughout the brain and spinal cord, orexins interact with various neuronal pathways to potentate divergent functions. In this review, we summarize recent progress in the physiological, neuroanatomical, and molecular studies of the novel neuropeptide orexins (hypocretins).Key words: orexins (hypocretins), hypothalamus, lateral hypothalamus, feeding behavior, energy homeostasis, neurons.

Modification of intracranial self-stimulation by hunger satiety

1962 ◽  
Vol 203 (3) ◽  
pp. 537-540 ◽  
Author(s):  
Harold A. Wilkinson ◽  
Talmage L. Peele
Keyword(s):  
Food Intake ◽  
Lateral Hypothalamus ◽  
Implanted Electrodes ◽  
Feeding Stimulation ◽  
Modifying Effect ◽  
Satiety Center ◽  
Feeding Center ◽  
Self Stimulation

The modifying effect of hunger satiety on intracranial electrical self-stimulation through implanted electrodes has been studied in cats. A feeding center was confirmed in the lateral hypothalamus in which self-stimulation was uniformly "positively rewarding." The positive-reward self-stimulation behavior so elicited was inhibited by prior feeding and was augmented by hunger— including postamygdalectomy hyperphagia. Self-stimulation in the rostral hypothalamic mating center was found not to be inhibited by feeding but to cause a decrease in subsequent food intake. Self-stimulation in other subcortical areas from which positive-reward behavior was elicited, both rostral and caudal to the above centers, was not affected by fasting-feeding. Stimulation in the ventromedial hypothalamic satiety center was uniformly "negatively rewarding."

Relationship of the middle hypothalamus to amygdalar hyperphagia

1960 ◽  
Vol 198 (6) ◽  
pp. 1315-1318 ◽  
Author(s):  
P. J. Morgane ◽  
A. J. Kosman
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
Lateral Hypothalamus ◽  
Ventromedial Nucleus ◽  
Dynamic Phase ◽  
Satiety Center ◽  
Feeding Center ◽  
Relationship Of

Stereotaxic lesions in the lateral hypothalamus of the cat at the level of the tuberal region were found not to alter food intake or body weight from preoperative control levels whereas lesions restricted to the ventromedial nuclei produced hyperphagia and obesity. Cats with combined lateral and ventromedial lesions showed no changes in food intake or body weight. Cats with combined amygdalar, lateral and ventromedial lesions developed hyperphagia and obesity but the rates of weight gain were about three times faster than occurred with amygdalectomy alone. Food intake in this group after operation more than doubled preoperative levels and the gain in weight of the group during the dynamic phase of obesity amounted to 23.6% as compared to 2.3% for normal and sham-operated controls. It is concluded that the lateral hypothalamus does not function as a ‘feeding’ center in the cat but that the ventromedial nucleus is probably a ‘satiety’ center. Furthermore it is probable that inhibitory amygdalar effects on food intake do not operate through the middle hypothalamus since hyperphagia and obesity results following destruction of the entire middle hypothalamus and amygdalae.

scholarly journals Contribution of Neuroinflammation to the Pathogenesis of Cancer Cachexia

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Alessio Molfino ◽  
Gianfranco Gioia ◽  
Filippo Rossi Fanelli ◽  
Alessandro Laviano
Keyword(s):  
Adipose Tissue ◽  
Food Intake ◽  
Proinflammatory Cytokines ◽  
Adaptive Response ◽  
Energy Homeostasis ◽  
Cancer Cachexia ◽  
Behavioral Changes ◽  
Brain Areas ◽  
Functional Changes ◽  
The Brain

Inflammation characterizes the course of acute and chronic diseases and is largely responsible for the metabolic and behavioral changes occurring during the clinical journey of patients. Robust data indicate that, during cancer, functional modifications within brain areas regulating energy homeostasis contribute to the onset of anorexia, reduced food intake, and increased catabolism of muscle mass and adipose tissue. In particular, functional changes are associated with increased hypothalamic concentration of proinflammatory cytokines, which suggests that neuroinflammation may represent the adaptive response of the brain to peripheral challenges, including tumor growth. Within this conceptual framework, the vagus nerve appears to be involved in conveying alert signals to the hypothalamus, whereas hypothalamic serotonin appears to contribute to triggering catabolic signals.

scholarly journals Endocrine factors in the hypothalamic regulation of food intake in females: a review of the physiological roles and interactions of ghrelin, leptin, thyroid hormones, oestrogen and insulin

2011 ◽  
Vol 24 (1) ◽  
pp. 132-154 ◽  
Author(s):  
V. Somogyi ◽  
A. Gyorffy ◽  
T. J. Scalise ◽  
D. S. Kiss ◽  
G. Goszleth ◽  
...  
Keyword(s):  
Food Intake ◽  
Energy Expenditure ◽  
Thyroid Hormones ◽  
Energy Homeostasis ◽  
The Body ◽  
Feedback Information ◽  
Hypothalamic Regulation ◽  
The Individual ◽  
Desire To Eat ◽  
The Brain

Controlling energy homeostasis involves modulating the desire to eat and regulating energy expenditure. The controlling machinery includes a complex interplay of hormones secreted at various peripheral endocrine endpoints, such as the gastrointestinal tract, the adipose tissue, thyroid gland and thyroid hormone-exporting organs, the ovary and the pancreas, and, last but not least, the brain itself. The peripheral hormones that are the focus of the present review (ghrelin, leptin, thyroid hormones, oestrogen and insulin) play integrated regulatory roles in and provide feedback information on the nutritional and energetic status of the body. As peripheral signals, these hormones modulate central pathways in the brain, including the hypothalamus, to influence food intake, energy expenditure and to maintain energy homeostasis. Since the growth of the literature on the role of various hormones in the regulation of energy homeostasis shows a remarkable and dynamic expansion, it is now becoming increasingly difficult to understand the individual and interactive roles of hormonal mechanisms in their true complexity. Therefore, our goal is to review, in the context of general physiology, the roles of the five best-known peripheral trophic hormones (ghrelin, leptin, thyroid hormones, oestrogen and insulin, respectively) and discuss their interactions in the hypothalamic regulation of food intake.

scholarly journals LGR4 and Its Ligands, R-Spondin 1 and R-Spondin 3, Regulate Food Intake in the Hypothalamus of Male Rats

Endocrinology ◽  
2014 ◽  
Vol 155 (2) ◽  
pp. 429-440 ◽  
Author(s):  
Ji-Yao Li ◽  
Biaoxin Chai ◽  
Weizhen Zhang ◽  
Danielle M. Fritze ◽  
Chao Zhang ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Food Intake ◽  
Neuropeptide Y ◽  
Paraventricular Nucleus ◽  
Median Eminence ◽  
Energy Homeostasis ◽  
Male Rats ◽  
The Third ◽  
The Brain

The hypothalamus plays a key role in the regulation of feeding behavior. Several hypothalamic nuclei, including the arcuate nucleus (ARC), paraventricular nucleus, and ventromedial nucleus of the hypothalamus (VMH), are involved in energy homeostasis. Analysis of microarray data derived from ARC revealed that leucine-rich repeat-containing G protein-coupled receptor 4 (LGR4) is highly expressed. LGR4, LGR5, and LGR6 form a subfamily of closely related receptors. Recently, R-spondin (Rspo) family proteins were identified as ligands of the LGR4 subfamily. In the present study, we investigated the distribution and function of LGR4–LGR6 and Rspos (1–4) in the brain of male rat. In situ hybridization showed that LGR4 is expressed in the ARC, VMH, and median eminence of the hypothalamus. LGR4 colocalizes with neuropeptide Y, proopiomelanocortin, and brain-derived neurotrophic factor neurons. LGR5 is not detectable with in situ hybridization; LGR6 is only expressed in the epithelial lining of the lower portion of the third ventricle and median eminence. Rspo1 is expressed in the VMH and down-regulated with fasting. Rspo3 is expressed in the paraventricular nucleus and also down-regulated with fasting. Rspos 1 and 3 colocalize with the neuronal marker HuD, indicating that they are expressed by neurons. Injection of Rspo1 or Rspo3 into the third brain ventricle inhibited food intake. Rspo1 decreased neuropeptide Y and increased proopiomelanocortin expression in the ARC. Rspo1 and Rspo3 mRNA is up-regulated by insulin. These data indicate that Rspo1 and Rspo3 and their receptor LGR4 form novel circuits in the brain to regulate energy homeostasis.

scholarly journals The Antiobesity Effects of Centrally Administered Neuromedin U and Neuromedin S Are Mediated Predominantly by the Neuromedin U Receptor 2 (NMUR2)

Endocrinology ◽  
2009 ◽  
Vol 150 (7) ◽  
pp. 3101-3109 ◽  
Author(s):  
Andrea Peier ◽  
Jennifer Kosinski ◽  
Kimberly Cox-York ◽  
Ying Qian ◽  
Kunal Desai ◽  
...  
Keyword(s):  
Food Intake ◽  
Energy Homeostasis ◽  
Central Administration ◽  
Diet Induced Obesity ◽  
Inhibit Food Intake ◽  
Selective Agonists ◽  
Treatment Of Obesity ◽  
The Brain ◽  
Deficient Mice

Neuromedin U (NMU) and neuromedin S (NMS) are structurally related neuropeptides that have been reported to modulate energy homeostasis. Pharmacological data have shown that NMU and NMS inhibit food intake when administered centrally and that NMU increases energy expenditure. Additionally, NMU-deficient mice develop obesity, whereas transgenic mice overexpressing NMU are lean and hypophagic. Two high-affinity NMU/NMS receptors, NMUR1 and NMUR2, have been identified. NMUR1 is predominantly expressed in the periphery, whereas NMUR2 is predominantly expressed in the brain, suggesting that the effects of centrally administered NMU and NMS are mediated by NMUR2. To evaluate the role of NMUR2 in the regulation of energy homeostasis, we characterized NMUR2-deficient (Nmur2−/−) mice. Nmur2−/− mice exhibited a modest resistance to diet-induced obesity that was at least in part due to reduced food intake. Acute central administration of NMU and NMS reduced food intake in wild-type but not in Nmur2−/− mice. The effects on activity and core temperature induced by centrally administered NMU were also absent in Nmur2−/− mice. Moreover, chronic central administration of NMU and NMS evoked significant reductions in body weight and sustained reductions in food intake in mice. In contrast, Nmur2−/− mice were largely resistant to these effects. Collectively, these data demonstrate that the anorectic and weight-reducing actions of centrally administered NMU and NMS are mediated predominantly by NMUR2, suggesting that NMUR2-selective agonists may be useful for the treatment of obesity.

scholarly journals Inconsistencies in the assessment of food intake

2012 ◽  
Vol 303 (12) ◽  
pp. E1408-E1418 ◽  
Author(s):  
Stephen C. Woods ◽  
Wolfgang Langhans
Keyword(s):  
Food Intake ◽  
Energy Intake ◽  
Body Fat ◽  
Energy Homeostasis ◽  
Behavioral Responses ◽  
Normal Function ◽  
Direct Proportion ◽  
Heated Debate ◽  
The Brain ◽  
Reducing Energy

Many peptides and other compounds that influence metabolism also influence food intake, and numerous hypotheses explaining the observed effects in terms of energy homeostasis have been suggested over the years. For example, cholecystokinin (CCK), a duodenal peptide secreted during meals that aids in digestion, also reduces ongoing food intake, thereby contributing to satiation; and insulin and leptin, hormones secreted in direct proportion to body fat, act in the brain to help control adiposity by reducing energy intake. These behavioral actions are often considered to be hard-wired, such that negative experiments, in which an administered compound fails to have its purported effect, are generally disregarded. In point of fact, failures to replicate the effects of compounds on food intake are commonplace, and this occurs both between and within laboratories. Failures to replicate have historically fueled heated debate about the efficacy and/or normal function of one or another compound, leading to confusion and ambiguity in the literature. We review these phenomena and their implications and argue that, rather than eliciting hard-wired behavioral responses in the maintenance of homeostasis, compounds that alter food intake are subjected to numerous influences that can render them completely ineffective at times and that a major reason for this variance is that food intake is not under stringent homeostatic control.

scholarly journals Pancreatic signals controlling food intake; insulin, glucagon and amylin

2006 ◽  
Vol 361 (1471) ◽  
pp. 1219-1235 ◽  
Author(s):  
Stephen C Woods ◽  
Thomas A Lutz ◽  
Nori Geary ◽  
Wolfgang Langhans
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Energy Homeostasis ◽  
Endocrine Pancreas ◽  
Situational Factors ◽  
Meal Size ◽  
Vagus Nerves ◽  
Social Emotional ◽  
Short Term ◽  
The Brain

The control of food intake and body weight by the brain relies upon the detection and integration of signals reflecting energy stores and fluxes, and their interaction with many different inputs related to food palatability and gastrointestinal handling as well as social, emotional, circadian, habitual and other situational factors. This review focuses upon the role of hormones secreted by the endocrine pancreas: hormones, which individually and collectively influence food intake, with an emphasis upon insulin, glucagon and amylin. Insulin and amylin are co-secreted by B-cells and provide a signal that reflects both circulating energy in the form of glucose and stored energy in the form of visceral adipose tissue. Insulin acts directly at the liver to suppress the synthesis and secretion of glucose, and some plasma insulin is transported into the brain and especially the mediobasal hypothalamus where it elicits a net catabolic response, particularly reduced food intake and loss of body weight. Amylin reduces meal size by stimulating neurons in the hindbrain, and there is evidence that amylin additionally functions as an adiposity signal controlling body weight as well as meal size. Glucagon is secreted from A-cells and increases glucose secretion from the liver. Glucagon acts in the liver to reduce meal size, the signal being relayed to the brain via the vagus nerves. To summarize, hormones of the endocrine pancreas are collectively at the crossroads of many aspects of energy homeostasis. Glucagon and amylin act in the short term to reduce meal size, and insulin sensitizes the brain to short-term meal-generated satiety signals; and insulin and perhaps amylin as well act over longer intervals to modulate the amount of fat maintained and defended by the brain. Hormones of the endocrine pancreas interact with receptors at many points along the gut–brain axis, from the liver to the sensory vagus nerve to the hindbrain to the hypothalamus; and their signals are conveyed both neurally and humorally. Finally, their actions include gastrointestinal and metabolic as well as behavioural effects.

scholarly journals Viral Infection Drives the Regulation of Feeding Behavior Related Genes in Salmo salar

2021 ◽  
Vol 22 (21) ◽  
pp. 11391
Author(s):  
David Muñoz ◽  
Ricardo Fuentes ◽  
Beatriz Carnicero ◽  
Andrea Aguilar ◽  
Nataly Sanhueza ◽  
...  
Keyword(s):  
Food Intake ◽  
Viral Infection ◽  
Feeding Behavior ◽  
Energy Homeostasis ◽  
Infectious Pancreatic Necrosis Virus ◽  
Complex Activity ◽  
Fish Remains ◽  
Pancreatic Necrosis Virus ◽  
The Brain

The feeding behavior in fish is a complex activity that relies on the ability of the brain to integrate multiple signals to produce appropriate responses in terms of food intake, energy expenditure, and metabolic activity. Upon stress cues including viral infection or mediators such as the proinflammatory cytokines, prostaglandins, and cortisol, both Pomc and Npy/Agrp neurons from the hypothalamus are stimulated, thus triggering a response that controls both energy storage and expenditure. However, how appetite modulators or neuro-immune cues link pathogenesis and energy homeostasis in fish remains poorly understood. Here, we provide the first evidence of a molecular linkage between inflammation and food intake in Salmon salar. We show that in vivo viral challenge with infectious pancreatic necrosis virus (IPNV) impacts food consumption by activating anorexic genes such as mc4r, crf, and pomcb and 5-HT in the brain of S. salar. At the molecular level, viral infection induces an overall reduction in lipid content in the liver, favoring the production of AA and EPA associated with the increment of elovl2 gene. In addition, infection upregulates leptin signaling and inhibits insulin signaling. These changes are accompanied by a robust inflammatory response represented by the increment of Il-1b, Il-6, Tnfa, and Pge2 as well as an increased cortisol level in vivo. Thus, we propose a model in which hypothalamic neurons respond to inflammatory cytokines and stress-related molecules and interact with appetite induction/inhibition. These findings provide evidence of crosstalk between pathogenesis-driven inflammation and hypothalamic–pituitary–adrenocortical axes in stress-induced food intake behavior in fish.

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