Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When rats are given access to a running-wheel in combination with food restriction, they will become hyperactive and decrease their food intake, a paradoxical phenomenon known as activity-based anorexia (ABA). Little is known about the regulation of the hypothalamic neuropeptides that are involved in the regulation of food intake and energy balance during the development of ABA. Therefore, rats were killed during the development of ABA, before they entered a state of severe starvation. Neuropeptide mRNA expression levels were analysed using quantitative real-time PCR on punches of separate hypothalamic nuclei. As is expected in a state of negative energy balance, expression levels of agouti-related protein (AgRP) and neuropeptide Y (NPY) were increased 5-fold in the arcuate nucleus (ARC) of food-restricted running ABA rats vs 2-fold in sedentary food-restricted controls. The co-regulated expression of AgRP and NPY strongly correlated with relative body weight and white adipose tissue mass. Arcuate expression of pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) was reduced 2-fold in the ABA group. In second-order neurons of the lateral hypothalamic area (LHA), melanin-concentrating hormone (MCH) mRNA expression was upregulated 2-fold in food-restricted running rats, but not in food-restricted sedentary controls. Prepro-orexin, CART and corticotropin-releasing hormone expression levels in the LHA and the paraventricular nucleus (PVN) were unchanged in both food-restricted groups. From this study it was concluded that during the development of ABA, neuropeptides in first-order neurons in the ARC and MCH in the LHA are regulated in an adequate response to negative energy balance, whereas expression levels of the other studied neuropeptides in secondary neurons of the LHA and PVN are unchanged and are probably regulated by factors other than energy status alone.
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PMID:Hypothalamic neuropeptide expression following chronic food restriction in sedentary and wheel-running rats. 1621 17

Hypothalamic neurons that express neuropeptide Y (NPY) and agouti-related protein (AgRP) are thought to be critical regulators of feeding behavior and body weight. To determine whether NPY/AgRP neurons are essential in mice, we targeted the human diphtheria toxin receptor to the Agrp locus, which allows temporally controlled ablation of NPY/AgRP neurons to occur after an injection of diphtheria toxin. Neonatal ablation of NPY/AgRP neurons had minimal effects on feeding, whereas their ablation in adults caused rapid starvation. These results suggest that network-based compensatory mechanisms can develop after the ablation of NPY/AgRP neurons in neonates but do not readily occur when these neurons become essential in adults.
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PMID:NPY/AgRP neurons are essential for feeding in adult mice but can be ablated in neonates. 1625 86

In invertebrates, neuropeptide F (NPF) peptides share structural similarity with vertebrate neuropeptide Y, which regulates food consumption, circadian rhythms, anxiety, and other physiological processes. The insect neuropeptide F receptors belong to the G protein-coupled receptor (GPCR) rhodopsin family. We have cloned the fire ant putative short NPF receptor using PCR and RACE methods. The complete 2,185-bp cDNA encodes a 387-residue protein with a predicted GPCR seven transmembrane region structure. We propose that the sequence of the honey bee short NPF receptor, which has not yet been annotated, encodes a protein of 393 residues. In fire ant mated queens, receptor transcripts were detected in the brain, midgut, hindgut, Malpighian tubules, fat body, and ovaries. The highest transcriptional expression was found in the brain. The downregulation of the fire ant short NPF receptor transcriptional expression in the brain with starvation suggests that the short NPF signal transduction cascade may play a role in feeding regulation in fire ant mated queens.
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PMID:The short neuropeptide F-like receptor from the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). 1655 71

For many years, the ketogenic diet, including recent variants such the medium-chain triglyceride (MCT) diet, has been used with good clinical results in the management of refractory epilepsies, particularly in children. The antiepileptic effects of the diet, like the antiepileptic effects of starvation, have been attributed to accumulation of ketones, and there are experimental data in animal models to support this hypothesis. Recently, new data about the neuroendocrine response to the acute phase reaction (stress) have emerged, indicating involvement of various neuropeptides, including neuropeptide Y (NPY), which is considered as an endogenous anticonvulsant. The release of NPY is also stimulated by nutrients in the gut, particularly fats. Long-chain and, to a greater extent, medium-chain triglycerides, which are components of the ketogenic diet, stimulate NPY secretion. This effect may explain the improvement in seizure control after starvation, use of the classical ketogenic diet, and use of the MCT diet.
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PMID:Is the antiepileptic effect of the ketogenic diet due to ketones? 1771 80

Hypothalamic neurons that express agouti-related protein (AgRP) and neuropeptide Y (NPY) are thought to be important for regulation of feeding, especially under conditions of negative energy balance. The expression of NPY and AgRP increases during lactation and may promote the hyperphagia that ensues. We explored the role of AgRP neurons in reproduction and lactation, using a mouse model in which AgRP-expressing neurons were selectively ablated by the action of diphtheria toxin. We show that ablation of AgRP neurons in neonatal mice does not interfere with pregnancy, parturition, or lactation, suggesting that early ablation allows compensatory mechanisms to become established. However, ablation of AgRP neurons after lactation commences results in rapid starvation, indicating that both basal feeding and lactation-induced hyperphagia become dependent on AgRP neurons in adulthood. We also show that constitutive inactivation of Npy and Agrp genes does not prevent pregnancy or lactation, nor does it protect lactating dams from diphtheria toxin-induced starvation.
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PMID:Role of agouti-related protein-expressing neurons in lactation. 1797 21

Ablation of inhibitory agouti-related protein (AgRP)-expressing neurons in the arcuate nucleus that also synthesize gamma-amino-butyric acid (GABA) and neuropeptide Y in adult mice leads to starvation within 1 week. The removal of inhibition from the AgRP neurons onto neighboring proopiomelanocortin neurons and their common postsynaptic neurons is predicted to stimulate melanocortin signaling, which is known to inhibit appetite. To examine the importance of uncontrolled melanocortin signaling in mediating starvation in this model, we ablated AgRP neurons in A(y)/a mice that have chronic blockade of the melanocortin signaling. The blockade of melanocortin signaling did not ameliorate the rate of starvation. On both WT and A(y)/a genetic backgrounds, there was a progressive decrease in meal frequency after AgRP neuron ablation. Surprisingly, intraoral feeding also was dramatically reduced after the ablation of AgRP neurons. These results indicate that both the appetitive and consummatory aspects of feeding become impaired in a melanocortin-independent manner after AgRP neuron ablation.
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PMID:Starvation after AgRP neuron ablation is independent of melanocortin signaling. 1827 80

Outcome in anorexia nervosa remains poor and a new way of looking at this condition is therefore needed. To this aim, we review the effects of food restriction and starvation in humans. It is suggested that body weight remains stable and relatively low when the access to food requires a considerable amount of physical activity. In this condition, the human homeostatic phenotype, body fat content is also low and as a consequence, the synthesis and release of brain neurotransmitters are modified. As an example, the role of neuropeptide Y is analyzed in rat models of this state. It is suggested that the normal behavioral role of neuropeptide Y is to facilitate the search for food and switch attention from sexual stimuli to food. Descriptive neuroendocrine studies on patients with anorexia nervosa have not contributed to the management of the patients and the few studies in which hormones have been administered have, at best, reversed an endocrine consequence secondary to starvation. In a modified framework for understanding the etiology and treatment of anorexia nervosa it is suggested that the condition emerges because neural mechanisms of reward and attention are engaged. The neural neuropeptide Y receptor system may be involved in the maintenance of the behavior of eating disorder patients because the localization of these receptors overlaps with the neural systems engaged in cue-conditioned eating in limbic and cortical areas. The eating behavior of patients with anorexia nervosa, and other eating disorders as well, is viewed as a cause of the psychological changes of the patients. Patients are trained to re-learn normal eating habits using external support and as they do, their symptoms, including the psychological symptoms, dissolve.
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PMID:Behavioral neuroendocrinology and treatment of anorexia nervosa. 1860 16

The anx/anx mouse displays poor appetite and lean appearance and is considered a good model for the study of anorexia nervosa. To identify new genes involved in feeding behavior and body weight regulation we performed an expression profiling in the hypothalamus of the anx/anx mice. Using commercial microarrays we detected 156 differentially expressed genes and validated 92 of those using TaqMan low-density arrays. The expression of a set of 87 candidate genes selected based on literature evidences was also quantified by TaqMan low-density arrays. Our results showed enrichment in deregulated genes involved in cell death, cell morphology, and cancer, as well as an alteration of several signaling circuits involved in energy balance including neuropeptide Y and melanocortin signaling. The expression profile along with the phenotype led us to conclude that anx/anx mice resemble the anorexia-cachexia syndrome typically observed in cancer, infection with human immunodeficiency virus or chronic diseases, rather than starvation, and that anx/anx mice could be considered a good model for the treatment and investigation of this condition.
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PMID:Hypothalamus transcriptome profile suggests an anorexia-cachexia syndrome in the anx/anx mouse model. 1881 57

In the Siberian hamster, seasonal weight loss occurs gradually over many weeks during autumn and winter. This is driven by a regulatory mechanism that is able to integrate duration of exposure to short days (SDs) with the size of body energy reserves. After food restriction in SDs, followed by ad libitum refeeding, body weight of the hamster does not return to its former level; rather, it increases to a level defined by the length of time spent in SDs. In this report, we show that components of the thyroid hormone system that are involved in seasonal weight loss change expression in response to 48 h of starvation. Eight weeks in an SD photoperiod induced weight loss in the Siberian hamster. In the hypothalamus of these hamsters, type II deiodinase expression was decreased and type III deiodinase expression was induced, but there was no change in hypothalamic neuropeptide Y or thyrotropin-releasing hormone gene expression. For the first time, we show that the thyroid hormone transporter monocarboxylate transporter 8 is expressed in tanycytes and is increased in response to an SD photoperiod. Food restriction (48 h of starvation) reversed the direction of gene expression change for type II and III deiodinase and monocarboxylate transporter 8 induced by SD photoperiods. Furthermore, fasting increased neuropeptide Y expression and decreased thyrotropin-releasing hormone expression. VGF, a gene upregulated in SDs in the dorsal region of the medial posterior area of the arcuate nucleus, was not changed by starvation. These data point to a mechanism whereby energy deprivation can interact with an SD photoperiod on hypothalamic tanycytes to regulate components of the thyroid hormone system involved in photoperiodic regulation of seasonal physiology.
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PMID:Photoperiod and acute energy deficits interact on components of the thyroid hormone system in hypothalamic tanycytes of the Siberian hamster. 1929 43

In spite of significant progress in pharmacotherapy the incidence of newly diagnosed cases of cardiovascular diseases and cardiovascular morbidity is alarmingly high. Treatment of hypertension or heart failure still remains a serious challenge. Continuous attempts are made to identify the mechanisms that decide about susceptibility to pathogenic factors, and to determine effectiveness of a specific therapeutic approach. Coincidence of cardiovascular diseases with metabolic disorders and obesity has initiated intensive research for their common background. In the recent years increasing attention has been drawn to disproportionately greater number of depressive disorders and susceptibility to stress in patients with coronary artery disease. An opposite relationship, i.e. a greater number of sudden cardiovascular complications in patients with depression, has been also postulated. Progress in functional neuroanatomy and neurochemistry provided new information about the neural network responsible for regulation of cardiovascular functions, metabolism and emotionality in health and under pathological conditions. In this review we will focus on the role of neuromodulators and neurotransmitters engaged in regulation of the cardiovascular system, neuroendocrine and metabolic functions in health and in pathogenesis of cardiovascular diseases and obesity. Among them are classical neurotransmitters (epinephrine and norepinephrine, serotonin, GABA), classical (CRH, vasopressin, neuropeptide Y) and newly discovered (orexins, apelin, leptin IL-1beta, TNF-alpha, ghrelin) neuropeptides, gasotransmitters, eicozanoids, endocannabinoids, and some other compounds involved in regulation of neuroendocrine, sympatho-adrenal and parasympathetic nervous systems. Special attention is drawn to those factors which play a role in immunology and inflammatory processes. Interaction between various neurotransmitter/neuromodulatory systems which may be involved in integration of metabolic and cardiovascular functions is analyzed. The survey gives evidence for significant disturbances in release or action of the same mediators in hypertension heart failure, obesity, diabetes mellitus, metabolic syndrome, starvation, chronic stress, depression and other psychiatric disorders. With regard to the pathogenic background of the cardiovascular diseases especially valuable are the studies showing inappropriate function of angiotensin peptides, vasopressin, CRH, apelin, cytokines and orexins in chronic stress, cardiovascular and metabolic diseases. The studies surveyed in this review suggest that multiple brain mechanisms interact together sharing the same neural circuits responsible for adjustment of function of the cardiovascular system and metabolism to current needs.
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PMID:Brain and cardiovascular diseases: common neurogenic background of cardiovascular, metabolic and inflammatory diseases. 2108 94


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