Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020175 (hunger)
 5,670 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Of the many factors that influence food intake, there is strong evidence that opioid and CCK peptides, which stimulate feeding and elicit satiety, respectively, are important components that may act in concert to regulate energy balance. Cholecystokinin peptides have been isolated in both the brain and gastrointestinal tract, and changes in concentration in the brain and in plasma have been shown to vary with feeding. Peripherally injected CCK has been shown to elicit satiety in many species, including humans, an effect that may be mediated in the CNS via the vagus. In several species, most notably the sheep, direct injection into the CSF potently decreases food intake. Questions remaining regarding the role of CCK peptides in eliciting satiety include the sites and mechanisms of action. It is unknown whether CCK acts directly on receptors, indirectly on some other parameter, or as a neurotransmitter. Although opioid peptides have also been localized in portions of both the periphery and brain, a specific physiological role for their presence has not yet been determined. Opioid peptides from three families--endorphins, enkephalins, and dynorphins--have been shown to stimulate feeding in various species. They have been active at several opioid receptor types in the CNS, but there is limited evidence to suggest they affect food intake when administered peripherally. In contrast, peripheral injection of opiate antagonists has effectively decreased food intake, an observation that led to the original hypothesis that opioids were involved in the hunger component in the control of food intake and that excess concentrations might be involved in the development of obesity. An increasing body of evidence supports the concept that opioid and CCK peptides may interact to control food intake, but the evidence is more suggestive than conclusive.
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PMID:Role of cholecystokinin and opioid peptides in control of food intake. 286 68

A unique profile of neurochemical events is proposed to occur in the diencephalon which is contingent upon the nutrient status of the animal. In this first of a series of investigations, we selected the lateral hypothalamus (LH) in order to determine its specific resting profile of monoaminergic neurotransmitters and their principal metabolites. The neuronal pattern of activity was studied during sated and fasted conditions as well as during a local glucoprivic challenge to the LH. After permanent guide cannulae for push-pull perfusion were implanted in female Sprague-Dawley rats, the LH was perfused repeatedly with an artificial CSF, at a rate of 20 microliters/min, in order to collect a series of 5.0 min samples. Aliquots of each perfusate were assayed directly using a high performance liquid chromatography system with electrochemical detection (HPLC-EC) for pg/microliter concentrations of norepinephrine (NE), dopamine (DA) and serotonin (5-HT). In comparison to the basal levels of amines during the sated condition, when the rat was food-deprived for 20-22 hr, the release of NE, DA, and 5-HT was significantly lower than that observed under the sated condition. Further, the turnover of NE in the LH was concurrently attenuated as reflected by the lower levels of MHPG in the perfusate, thus demonstrating the modification in catecholamine activity produced in the LH by the condition of hunger. When either 10 micrograms/microliters 2-deoxy-D-glucose (2-DG) or 4.0 mU/microliter insulin was incorporated into the CSF perfused in the LH, the efflux of DA was significantly enhanced independent of the state of satiation. In addition, the proportion of both NE and DA to 5-HT was likewise increased by either of these centrally acting substances, while the turnover of 5-HT was enhanced and NE and DA turnovers were reduced. Perfusion of 2-DG in the LH of the fasted rat caused a significant reduction in catecholamine turnover in terms of MHPG/NE, VMA/NE, DOPAC/DA and HVA/DA ratios. Moreover, 2-DG increased NE/5-HT while lowering the NE/DA ratio, and enhanced simultaneously the 5-HTOL/5-HT ratio. In the sated rat, 2-DG attenuated the release of 5-HT from the animal's LH, whereas insulin caused a shift in the proportions of NE/5-HT and DA/5-HT. Further, the peptide served to reduced the efflux of 5-HT, enhanced the turnover of 5-HT while diminishing DA turnover, and shifted the metabolism of NE from MHPG to VMA.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Monoamine transmitter activity in lateral hypothalamus during its perfusion with insulin or 2-DG in sated and fasted rat. 290 62

There is still much to learn of the sites and mechanisms of action of brain CCK peptides and their interaction with other brain peptides and neurotransmitters. The findings obtained from studies in sheep and other species provide evidence for brain CCK peptides functioning as important transmitters of hunger and satiety signals. We have hypothesized that signals, either neural or humoral, peripherally generated as a result of feeding induce secretion of CCK from specific (paraventricular) brain sites into the CSF (FIG. 1). Specialized ependymal cells, such as tanycytes, may take up CCK from the CSF for transport to receptor sites which mediate CCK's specific functions (such as changes in rumen motility, suppression of insulin secretion, and behavioral satiety). Evidence also exists to indicate the involvement of specific hypothalamic sites in either the release or the action of CCK.
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PMID:Central nervous system cholecystokinin and the control of feeding. 299 48

The purpose of this investigation was to determine the functional relationship between putative satiety peptides and endogenous norepinephrine (NE) activity in the hypothalamus. Permanent guide cannulae for push-pull perfusion were implanted stereotaxically in Sprague-Dawley rats so as to rest above the medial or lateral hypothalamus (LH). Post-operatively, the animals were either satiated with food and water, both available ad lib, or fasted for 18-22 hr prior to an experiment. To perfuse a site in the LH, paraventricular (PVN) or ventromedial nucleus (VMN), a concentric 29-23 ga push-pull cannula system was lowered to a pre-determined site, in most cases after catecholamine stores had been pre-labeled with [3H]-NE. During control tests, an artificial CSF was perfused at a rate of 20-25 microliter/min for 5-8 min with a 5 min interval between each sample. The addition of cholecystokinin (CCK) in a concentration of 2.0-6.0 ng/microliter to the CSF perfused in PVN or VMN of the satiated rat enhanced the efflux of NE; however, in the fasted animal CCK often suppressed the catecholamine's release. Perfused in the LH, CCK exerted opposite effects, typically augmenting NE output when the rat was fasted but not affecting the amine's activity during the sated condition. Proglumide (1.2 micrograms/microliter) attenuated CCK's effect in releasing NE when the antagonist was perfused in the PVN of the satiated rat. Similar experiments in which neurotensin (NT) was perfused in the LH, PVN and VMN revealed virtually the same inverse effects on NE release in the fasted and satiated rat, which again were anatomically specific. Finally, insulin and 2-deoxy-D-glucose (2-DG) exerted similar state-dependent effects on the release of NE within LH and PVN. Overall, the results suggest that CCK or other neuroactive peptide could serve as a "neuromodulator" of the pre-synaptic release of NE within classical hypothalamic structures which are thought to underlie both hunger and satiety. The state-dependent nature of the peptides' activity on the noradrenergic feeding mechanism implies that these substances constitute a pivotal portion of the profile of factors which impinge functionally upon the hypothalamic neurons responsible for the feeding response and its cessation.
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PMID:CCK and other peptides modulate hypothalamic norepinephrine release in the rat: dependence on hunger or satiety. 353 2

This study examined the localized action of neuropeptide Y (NPY) on monoamine transmitter activity in the hypothalamus of the unrestrained rat as this peptide induced hypothermia, spontaneous feeding or both responses simultaneously. A guide tube was implanted in the anterior hypothalamic pre-optic area (AH/POA) of Sprague-Dawley rats. Then either control CSF vehicle or NPY in a dose of either 100 ng/microliter or 250 ng/microliter was perfused by push-pull cannulae in this structure in the fully sated, normothermic rat. Successive perfusions were carried out at a rate of 20 microliters/min for 6.0 min with an interval of 6.0 min elapsing between each. Samples of perfusate were assayed by HPLC for their levels of dopamine (DA), norepinephrine (NE), serotonin (5-HT) and their respective metabolites. Whereas control CSF was without effect on body temperature (Tb) or feeding, repeated perfusions of NPY over 3.0 hr caused dose-dependent eating from 4 to 39 g of food, hypothermia of 0.9 to 2.3 degrees C or both responses concurrently. As the rats consumed 11-39 g of food, the efflux of NE, MHPG, DOPAC and 5-HT was enhanced significantly, whereas during the fall in Tb the efflux of NE, DOPAC and 5-HIAA from the AH/POA increased. When the Tb of the rat declined simultaneously with eating behavior, the levels in perfusate of DOPAC and HVA increased significantly while MHPG declined. During perfusion of the AH/POA with NPY the turnover of NE declined while DA and 5-HT turnover increased during hypothermia alone or when accompanied by feeding. These results demonstrate that the sustained elevation in NPY within the AH/POA causes a selective alteration in the activity of the neurotransmitters implicated in thermoregulation, satiety and hunger. These findings suggest that both DA and NE comprise intermediary factors facilitating the action of NPY on neurons involved in thermoregulatory and ingestive processes. The local activity of NPY on hypothalamic neurons apparently shifts the functional balance of serotonergic and catecholaminergic neurons now thought to play a primary role in the control of energy metabolism and caloric intake.
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PMID:Neuropeptide Y perfused in the preoptic area of rats shifts extracellular efflux of dopamine, norepinephrine, and serotonin during hypothermia and feeding. 882 34

Calling male toads were tested behaviourally for their prey catching responses to wormlike stimuli and assigned to groups of non-hungry and hungry depending on their prey catching motivation before being prepared for visual unit, massed unit and slow potential shift (SPS) recording from the optic tectum. Control recordings to visual stimuli were made before recording the effects of application of isotonic solutions containing concentrations of 0-41 mM K(+). Application of solution was followed by presentation of the visual stimulus while the solution still bathed the tectum. The best tectal responses were made to large square visual stimuli in the non-hungry toads, perhaps because recordings were made in the breeding season. Responses of the tectum to solution addition were significant in the concentration range of 7-17 mM K(+). Hungry toads showed an earlier, smaller response than non-hungry (sexually motivated) animals. When the visual stimulus was presented, there were unit and massed unit responses at all bathing solution concentrations, which were larger in non-hungry animals. These experiments revealed that toads motivated to feed respond earlier than non-hungry toads to application of artificial CSF to the tectum, though non-hungry toads responded best to the subsequent visual stimulus.
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PMID:Tectal responses to potassium loads and subsequent visual stimuli in the toad, Bufo bufo. 1512 74

Orexin-A and -B are hypothalamic peptides which, in the adult brain, are associated with arousal, increased vigilance, and the seeking and ingestion of food. Because the fetus is mostly asleep, and hunger is a physiological state unlikely to arise until birth, we hypothesized that orexigenic neurons in the lateral and dorso-medial hypothalamic areas (LHA, DMH) and their projections to the locus coeruleus (LC) would develop only near the time of birth. We therefore determined orexin expression in fetal sheep, where birth occurs over a tightly regulated interval of 146-148 days gestation. Immunohistochemistry was used to determine the presence and distribution of orexin-A positive fibres and cells at the level of the hypothalamus and LC in fetal (125-137 and 145+ days gestation age) and newborn sheep brains. Orexin was measured by radioimmunoassay in plasma samples taken from chronically catheterised fetal and newborn sheep, and in CSF taken from fetuses and lambs at postmortem. Orexin-A positive cells bodies were observed in the hypothalamus, and orexin-A fibres were found throughout all hypothalamic, thalamic, and brain stem regions of all the fetal and newborn brains examined. Orexin-A was present in plasma and CSF at similar concentrations in fetal and newborn sheep. The presence of orexin in hypothalamic neurons and CSF throughout late gestation suggests that orexinergic regulation of hunger, appetite and the sleep/wake cycle is inhibited, by mechanisms yet to be identified, until the time of parturition.
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PMID:Onset of feeding at birth--perinatal development of the hypothalamic mechanisms that induce appetite and feeding in the newborn. 1839 43