Activation of the rat hypothalamic supramammillary nucleus by food anticipation, food restriction or ghrelin administration.
Marie V Le MayCatherine HumeNancy SabatierErik SchéleTina BakeUlrika BergströmJohn MenziesSuzanne L DicksonPublished in: Journal of neuroendocrinology (2019)
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.
Keyphrases
- growth hormone
- induced apoptosis
- cell cycle arrest
- white matter
- signaling pathway
- endoplasmic reticulum stress
- multiple sclerosis
- high resolution
- human health
- cell proliferation
- machine learning
- resting state
- genome wide
- mass spectrometry
- pi k akt
- single cell
- chemotherapy induced
- dna methylation
- electronic health record
- artificial intelligence
- high density
- case control