How good is your food? Hormones and specialized brain cells control feeding behavior in mice — ScienceDaily

Knowing when it’s time to eat and when to stop eating is critical to the survival and health of humans and animals alike. Researchers at the Max Planck Institute for Biointelligence investigated how the brain regulates feeding behavior in mice. The researchers found that the hormone ghrelin activates specialized nerve cells in a brain region known as the amygdala. Here, interactions between ghrelin and specialized neurons drive food consumption, conveying feelings of hunger and the pleasant and rewarding emotions associated with eating.

Hunger is a powerful sensation with important biological underpinnings. It signals the body to seek food, an important behavior to prevent starvation and ensure survival. When we are hungry, we crave food. And when we finally get to eat, our bodies reward us with pleasant emotions and an overall state of well-being.

A network of brain circuits and signaling pathways regulates eating behavior in humans and animals and elicits associated sensations. His one of the central figures in this network is the hormone ghrelin. It is released by gastric cells when humans and animals are hungry or fasting and promotes feeding behavior.

The Rudiger Klein Department of the Max Planck Institute for Biointelligence studies the brain networks underlying feeding behavior in mice. To this end, the researchers performed a thorough analysis of different cell types in a brain region known as the centriole amygdala. “Until now, the amygdala has been primarily studied in relation to emotions such as fear and reward, but it was thought that regulation of feeding was performed in other parts of the brain, such as the hypothalamus.” , says Christian Peters, a postdoctoral fellow on the study. Department.

9 cell clusters

Peters et al. dissected individual cells in the central amygdala to study messenger RNA molecules, the working copies of the cell’s genes. Analysis revealed that the cells were organized into nine distinct cell clusters. Some of these clusters promote appetite, while others suppress appetite and modulate messenger RNA production when mice are fed or fasted.

“We now have a better understanding of the diversity of cell types and the physiological processes that drive feeding in the mid-amygdala,” says Ruediger Klein. “Our study is the first to show that the ‘hunger hormone’ ghrelin also acts on cells in the mid-amygdala.” and increase food intake.

Multiple Functions of Ghrelin

Scientists have found that Htr2a neurons activate after an overnight fast or when stimulated by the hormone ghrelin. The cells also responded when the researchers fed the mice. “We think ghrelin serves multiple functions,” explains Christian-Peters. “When mice are hungry, ghrelin activates appetizing brain regions, making it easier for the animal to eat. In addition, the hormone enhances the activity of brain circuits, such as the amygdala, that provide rewards, and is likely to be an incentive to eat additional food.” In this way, ghrelin increases food palatability in proportion to the mouse’s current satiety level.

After a fasting meal, Htr2a neuron activity was not required to initiate feeding when animals were very hungry. This is probably because under these conditions the palatability of the food is not so important. “Other brain circuits, such as the hypothalamus, which regulate the body’s metabolism, send signals to mice that eating is important for survival,” says Christian-Peters.

Feelings of hunger and satiety, as we all probably know from the pleasure that comes with eating good food, have a huge impact on not only our physical but also our mental health. “The neural networks that convey these emotions are clearly related to those that control eating, but exactly how they influence each other is not fully understood,” says Rudiger. Mr Klein says

“Clarifying these links will allow us to better understand the neuronal processes involved in pathological eating behaviors such as binge eating,” concludes Christian Peters. “There are many biological factors that contribute to such complex behaviors, and understanding these factors requires looking at physiological processes.” Ultimately, this knowledge will alleviate eating disorders. may lead to new therapeutic approaches for For now, this work lays the groundwork for further research to investigate how specific neuronal populations are involved in neural circuits that control feeding. It also adds another important piece to the puzzle of understanding how the brain coordinates behavior.

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