About twenty years ago, there was a major step forward in scientific understanding of obesity when researchers discovered that our appetite is controlled by a key substance called leptin.
CANADA – Leptin is a hormone that is produced by our fat cells which is supplied by the blood to the brain that informs us that we are full and stop eating. But although shortly after receptors for leptin in the hypothalamus they were discovered, an area of the brain that regulates food intake and body weight, it has still remained unclear exactly how leptin is detected.
So, about four years ago the team of Dr. Maia Kokoeva of McGill University in Canada, set out to explore which brain cells could play a role in the process of detecting leptin and weight gain. The answer was to in an area of the brain known as the median eminence.
The median eminence is a brain structure at the base of the hypothalamus. It looks like a busy communications hub or central market through which hormones and substances of various types travel in both directions between the brain and the bloodstream to ensure that the body is running smoothly.
Kokoeva, Tina Djogo and Sarah Robins have now discovered that without a group of particular cells (known as NG2 glial cells) in place in the median eminence, leptin receptors in the brain never receive messages from the body saying it is satiated.
Given the large flow of signals passing through the median eminence, the research team wondered if NG2 glial cells might be involved in the detection of leptin and therefore in appetite control. To test this, a drug was used to kill NG2 glial cells in the median eminence of a group of mice followed by observing whether there was any difference in food consumption. The results were conclusive.
The study was published in the journal Cell Metabolism.