WHY does eating
feel so good? The secret may lie in the head, not in the stomach, U.S.
researchers reported last Thursday.
Tests on rats show that the appetite hormone ghrelin acts on pleasure
receptors in the brain.
“In mice and rats ghrelin triggers the same neurons as delicious food,
sexual experience, and many recreational drugs; that is, neurons that provide
the sensation of pleasure and the expectation of reward,” the researchers wrote
on last Friday’s issue of the Journal of Clinical Investigation.
“These neurons produce dopamine and are located in a region of the brain
known as the ventral tegmental area (VTA),” wrote the researchers, headed by Dr.
Tamas Horvath of the Yale University School of Medicine in Connecticut.
Horvath’s team found that ghrelin, itself only discovered in the last
decade, acts on a molecular structure on brain cells called GHSR for
short.
When ghrelin was infused into this area of the rats’ brains, they ate as
hungrily as they did after being kept hungry overnight, the researchers
said.
Ghrelin is produced in the gut and triggers the brain to promote eating.
Horvath said it might be possible to design a drug that interferes with GHSR and
thus help people with eating disorders.
