Scientists Found an On/Off Switch for Appetite

What controls appetite? Well, until recently, many researchers believed that it was “something” in the brain. A recent discovery using mice may have lead researchers to the on/off switch in the brain for a person’s appetite.

The researchers at Johns Hopkins took a look inside the brain of a mouse. They found that the brain’s learning and memory system have nerve cells that signals to the mice as to when to stop eating (or when they are still hungry). They discovered these nerve cells send signals to the mouse’s brain and then shortly after the mouse will stop eating. This research may be able to lead to assistance for people with no “off” switch on their appetites (which often times leads to obesity).

They discovered that the enzyme OGT in the brain was the nerve cell sending messages to the brain to stop eating. Researchers did this by deleting the gene that codes for the OGT enzyme. When they deleted this gene they noticed that the weight of the mice doubled in about three weeks. The buildup, according to researchers was simply fat deposits and no muscle whatsoever.

Researchers compared the mice missing their OGT to others that still had the gene. Both groups were eating the same number of meals (18 a day), however, those with missing OGT ate for longer periods of time. However, when the mice with missing OGT had restricted diets, they did not gain any weight.

This suggests that not having OGT within the brain could significantly influence the mouse’s ability to get full (or to know when they are full). Researchers believe the sugar levels in the bloodstream may be involved in triggering the brain’s on and off switch for appetite. However, when this switch fails, it can quickly lead to obesity.

Scientists did not set out to find this information. They sort of stumbled upon it. They discovered it while looking at the strength of connections between nerve cells in the brains of mice. They were looking at this connections in hopes of finding information important for learning and memory. They also wanted to see what the OGT gene really did and what would happen if it disappeared.

The teams of researchers determined that, “While researching the brain’s learning and memory system, scientists at Johns Hopkins say they stumbled upon a new type of nerve cell that seems to control feeding behaviors in mice. The finding, they report, adds significant detail to the way brains tell animals when to stop eating and, if confirmed in humans, could lead to new tools for fighting obesity.”

Although the brain is a hard thing to study, scientists are making strides in better understanding how it works. The OGT gene could tell researchers a lot about the brain and how it works. The gene is also in the same region as learning and memory. The findings in this most recent study could help researchers learn how people remember things and possibly even help people get memories back that they’ve lost.

Photo: Flickr: Global Panorama