76 research outputs found
Activation of the rat hypothalamic supramammillary nucleus by food anticipation, food restriction or ghrelin administration
The circulating orexigenic hormone ghrelin targets many brain areas involved in feeding control and signals via a dedicated receptor, the growth hormone secretagogue receptor 1A. One unexplored target area for ghrelin is the supramammillary nucleus (SuM), a hypothalamic area involved in motivation and reinforcement and also recently linked to metabolic control. Given that ghrelin binds to the SuM, we explored whether SuM cells respond to ghrelin and/or are activated when endogenous ghrelin levels are elevated. We found that peripheral ghrelin injection activates SuM cells in rats, reflected by an increase in the number of cells expressing c‐Fos protein in this area, as welll as by the predominantly excitatory response of single SuM cells recorded in in vivo electrophysiological studies. Further c‐Fos mapping studies reveal that this area is also activated in rats in situations when circulating ghrelin levels are known to be elevated: in food‐restricted rats anticipating the consumption of food and in fed rats anticipating the consumption of an energy‐dense food. We also show that intra‐SuM injection of ghrelin induces a feeding response in rats suggesting that, if peripheral ghrelin is able to access the SuM, it may have direct effects on this brain region. Collectively, our data demonstrate that the SuM is activated when peripheral ghrelin levels are high, further supporting the emerging role for this brain area in metabolic and feeding control
Akhet Khufu: Archaeo-astronomical Hints at a Common Project of the Two Main Pyramids of Giza, Egypt
Abstract. The architectural complexes composed by the two main pyramids of Giza together with their temples are investigated from an interdisciplinary point of view, taking into account their astronomical alignments as well as their relationships with the visible landscape. Combining already known facts together with new clues, the work strongly supports the idea that the two complexes were conceived as parts of a common project
Shanghaied into the future: the Asianization of the future Metropolis in post-Blade Runner cinema
The clichéd 1930–1950 Western cinematic images of Shanghai as a fascinating den of iniquity, and, in contrast, as a beacon of modernity, were merged in Fritz Lang’s Metropolis. As a result, a new standard emerged in science ction lms for the representation of future urban conglomerates: the Asianized metropolis. e standard set by this lm, of a dark dystopian city, populated by creatures of all races and genetic codes, will be adopted in most of the representations of future cities in non-Asian cinema. is article traces the representation of Shanghai in Western cinema from its earliest days (1932– Shanghai Express) through Blade Runner (1982) to the present (2013– Her). Shanghai, already in the early 1930s, sported extremely daring examples of modern architecture and, at the same time, in non-Asian cinema, was represented as a city of sin and depravity. is dualistic representation became the standard image of the future Asianized city, where its debauchery was o en complemented by modernity; therefore, it is all the more seedy. Moreover, it is Asianized, the “Yellow Peril” incarnated in a new, much more subtle, much more dangerous way. As such, it is deserving of destruction, like Sodom and Gomorrah
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Intranasal Delivery of a Ghrelin Mimetic Engages the Brain Ghrelin Signaling System in Mice
Ghrelin, the endogenous ligand of the growth hormone secretagogue receptor (GHSR), promotes food intake and other feeding behaviors, and stimulates growth hormone (GH) release from the pituitary. Growth hormone secretagogues (GHS), such as GHRP-6 and MK-0677, are synthetic GHSR ligands that activate orexigenic neuropeptide Y neurons that coexpress agouti-related peptide (AgRP) in the arcuate nucleus of the hypothalamus when administered systemically. Systemic GHRP-6 also stimulates GH release in humans and rats. Thus, GHS and ghrelin have therapeutic relevance in patients who could benefit from its orexigenic and/or GH-releasing effects. This study examined whether intranasal delivery of ghrelin, GHRP-6, or MK-0677 engages the brain ghrelin signaling system.Effective compounds and doses were selected based on increased food intake after intranasal application in mice. Only GHRP-6 (5 mg/kg) increased food intake without adverse effects, prompting detailed analysis of meal patterns, neuronal activation in the arcuate nucleus (via Fos mapping) and neurochemical identification of c-fos messenger RNA (mRNA)-expressing neurons using RNAscope. We also assessed the effect of intranasal GHRP-6 on serum GH levels.Intranasal GHRP-6 increased food intake by increasing meal frequency and size. Fos expression in the arcuate nucleus was higher in GHRP-6-treated mice than in saline controls. When examining the neurochemical identity of c-fos-mRNA-expressing neurons, we found coexpression with 63.5 +/- 1.9% Ghsr mRNA, 79 +/- 6.8% Agrp mRNA, and 11.4 +/- 2.5% Ghrh mRNA, demonstrating GHRP-6's ability to engage arcuate nucleus neurons involved in food intake and GH release. Additionally, intranasal GHRP-6 elevated GH serum levels. These findings suggest that intranasal GHRP-6, but not ghrelin or MK-0677, can engage the brain ghrelin signaling system
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