| 1. |
- Bomberg, Eric M, et al.
(författare)
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Central ghrelin induces feeding driven by energy needs not by reward
- 2007
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Ingår i: NeuroReport. - 0959-4965 .- 1473-558X. ; 18:6, s. 591-595
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Tidskriftsartikel (refereegranskat)abstract
- Centrally administered ghrelin, the endogenous agonist of the growth hormone secretegogue receptor, powerfully stimulates food intake. Although the orexigenic action of this peptide has been well established, it remains unclear whether ghrelin-induced hyperphagia is driven by energy needs or by reward. In our study ghrelin was injected into the lateral cerebral ventricle or the hypothalamic paraventricular nucleus of rats given a choice between a palatable yet calorie-dilute sucrose solution and a calorically dense chow. As a result of intraventricular and hypothalamic paraventricular ghrelin injections, animals increased intake of chow but not sucrose. When the sucrose solution was offered as the only source of calories, rats treated with ghrelin infused in the ventricle and site-specifically increased sucrose consumption. These results suggest that the primary effect of ghrelin is to stimulate food intake to satisfy energy needs.
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| 2. |
- Olszewski, Pawel K., et al.
(författare)
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Alpha-melanocyte stimulating hormone and ghrelin : central interaction in feeding control
- 2007
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Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 28:10, s. 2084-2089
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Tidskriftsartikel (refereegranskat)abstract
- Alpha-melanocyte stimulating hormone (alpha-MSH) and ghrelin play significant yet opposite roles in the regulation of feeding: alpha-MSH inhibits, whereas ghrelin stimulates consumption. The two peptidergic systems may interact in the process of food intake control. A single report published thus far has shown that a synthetic agonist of the melanocortin receptors, MTII, injected in the hypothalamic paraventricular nucleus (PVN) decreases feeding generated by ghrelin. We found that very low doses of alpha-MSH and MTII administered ICV significantly reduced ghrelin-dependent hyperphagia. However, an endogenous molecule, alpha-MSH, infused in the PVN did not exert an inhibitory effect on ghrelin-induced consumption, whereas the effective dose of PVN MTII exceeded that necessary to decrease short-term deprivation-induced feeding. We conclude that it is likely that in feeding regulation alpha-MSH and ghrelin "interact" at the central nervous system level, but the involvement of the PVN in this interaction appears questionable.
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| 3. |
- Olszewski, Pawel K, et al.
(författare)
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Intraventricular ghrelin activates oxytocin neurons : implications in feeding behavior
- 2007
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Ingår i: NeuroReport. - 0959-4965 .- 1473-558X. ; 18:5, s. 499-503
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Tidskriftsartikel (refereegranskat)abstract
- Ghrelin affects behavioral and physiological responses, such as feeding or the activity of the HPA axis. Distribution of its receptor in central sites involved in neuroendocrine control, including the hypothalamic paraventricular nucleus, indicates that interplay with multiple neuropeptidergic systems underlies ghrelin's actions. We report that intracerebroventricular ghrelin increases c-Fos immunoreactivity of oxytocin neurons in magno and parvocellular portions of the paraventricular nucleus. The orexigenic response to ghrelin administered at the dose that activates oxytocin neurons can be further elevated by pretreatment with a selective oxytocin receptor antagonist. Our data suggest that oxytocin may be responsible for the mediation of some effects induced by ghrelin. Modifications in the activity of the oxytocin system may alter some of these effects.
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