AMPK is involved in regulating feeding behavior
Recently, a study published in Neuron demonstrates that a protein called AMPK regulates brain nerve cells that control hunger. The protein can be activated by fasting. In addition, AMPK has an impact on the formation of connections between neurons.
These findings could help to understand how feeding behavior is modulated, and have important meanings for future research on synapse formation.
AgRP neurons in the brain are responsible for controlling hunger. The abnormal function of these neurons can result in anorexia or obesity. So understanding what modulates AgRP neurons is very important.
Nerve cells that express AgRP affect feeding behavior. Fasting and ghrelin can activate the AgRP neurons, while leptin can suppress them. However, the molecular mechanism behind these processes remains unclear.
In this work, the researchers looked at the protein AMPK, which plays a role in cellular energy homeostasis. Although it's known that fasting and ghrelin can also increase the activity of the AMPK protein, how AMPK affects nerve cells is still unknown.
The experiments showed that fasted mice had much higher AMPK activity in AgRP neurons than mice that were sated. In further research, mice were genetically engineered to have continuously activated AMPK. The researchers found that the firing of AgRP neurons was increased in these animals. And this resulted in greater food intake, body weight, and fat mass. On the other hand, inhibiting AMPK activity reduced AgRP neuron activity.
Another important finding was that AMPK also changed the ability of AgRP neurons to form dendritic spines. Boosting AMPK activity led to higher dendritic spine density, whereas inhibiting AMPK activity negatively affected spine formation.