A hormone called amylin can tell us to stop overeating (even if we really, really love cookies and swear we only want one more)

or technically,

Amylin acts in the lateral dorsal tegmental nucleus to regulate energy balance Through GABA Signaling.

[See Original Abstract on Pubmed]

Authors of the study: David J. Reiner, Elizabeth G. Mietlicki-Baase, Diana R. Olivos, Lauren E. McGrath, Derek J. Zimmer, Kieran Koch-Laskowski, Joanna Krawczyk, Christopher A. Turner, Emily E. Noble, Joel D. Hahn, Heath D. Schmidt, Scott E. Kanoski, Matthew R. Hayes

Have you ever had one too many chocolate chip cookies? Maybe you’ve eaten so much that you felt sick? Sometimes we eat when we’re not hungry. This is because, in addition to filling us up, delicious food activates the parts of our brainThe brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. that make us feel pleasure (also known as the brainThe brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals.’s “reward areas”). Dave Reiner, a neuroscience graduate student in Matt Hayes’s lab, wondered if some people feel the rewarding effects of food more strongly than others. To figure this out, he asked whether one of the brainThe brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals.’s specialized reward areas can sense a hormone called amylin, which gets released when you’re full. Dave thought that if the reward areas could sense amylin, then they might be able to tell you to stop eating, no matter how delicious your grandma’s cookies are....

Here’s how this could work: after a meal, your pancreas produces a hormone called amylin that travels through your bloodstream into your brainThe brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals.. Once it’s in your brainThe brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals., amylin binds to proteinsAn essential molecule found in all cells. DNA contains the recipes the cell uses to make proteins. Examples of proteins include receptors, enzymes, and antibodies. called “amylin receptorsA protein on a cell’s surface that binds to specific molecules (i.e. other proteins or chemicals). Typically, a receptor is said to fit with its partner molecule(s) like a lock and key. When bound by the right molecule, receptors often transmit signals to the rest of the cell..” BrainThe brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. areas that contain these receptorsA protein on a cell’s surface that binds to specific molecules (i.e. other proteins or chemicals). Typically, a receptor is said to fit with its partner molecule(s) like a lock and key. When bound by the right molecule, receptors often transmit signals to the rest of the cell. can sense amylin, which tells them that you are full. Dave found that there are amylin receptorsA protein on a cell’s surface that binds to specific molecules (i.e. other proteins or chemicals). Typically, a receptor is said to fit with its partner molecule(s) like a lock and key. When bound by the right molecule, receptors often transmit signals to the rest of the cell. in a reward area called the lateral dorsal tegmental nucleus (LDTg). This made Dave wonder what amylin might be doing in the LDTg. He was especially curious because the LDTg is best known as a reward area, not as a part of the brainThe brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. that controls hunger or metabolism. To test this, Dave used a drug to turn on the amylin receptorsA protein on a cell’s surface that binds to specific molecules (i.e. other proteins or chemicals). Typically, a receptor is said to fit with its partner molecule(s) like a lock and key. When bound by the right molecule, receptors often transmit signals to the rest of the cell. specifically in the LDTg of rats. And what he saw was really exciting: rats that received the drug ate less food and lost weight (when compared with rats that received a placebo).

This finding leads to another interesting question -- how does amylin in the LDTg limit food intake and cause weight loss? Dave didn’t do any experiments to figure this out, but he did have an idea of how it might work: because the brainThe brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. cells inside the LDTg are inhibitory (this means they send “stop” signals to other brainThe brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. cells), Dave hypothesized that these “stop” signals are what caused the rats (and could cause you) to eat less. These findings could be really important for many Americans (over a third of the total US population) who struggle with obesity. If we can understand how hormones act in the brainThe brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. to make us feel hungry or full, we can potentially create new treatments for healthy weight management.
NGG GLIAhunger, obesity