It’s all shrinking-brain stuff this week in the health news world, it seems. Yesterday, we reported that obesity (as well as smoking, diabetes and high blood pressure) in midlife causes brains to shrink at an accelerated clip.
Today, we learn that dieting causes certain brain cells to start eating bits of themselves -- triggering a hunger response.
Damned if you do, damned if you don’t.
This act of self-cannibalism was reported by scientists at the Albert Einstein College of Medicine in the journal Cell Metabolism. It occurs in mice. But there’s a very good chance it would also happen in our heads as well, since many metabolic processes are very similar between our two species -- especially ancient important ones such as “eat more when you’re burning more calories than you’re taking in.”
The neurons in question are specific ones in the hypothalamus that are involved in appetite regulation. What happens is this: The neurons in starved mice start chomping on themselves in a process known technically as autophagy (“self-eat”). As a result, certain fatty acids are released, and these cause a spike in amounts of a hunger-signaling peptide, known for short as AgRP.
When this process was blocked in experiments, mice didn’t chow down as much after a period of fasting, and thus remained lean.
There should not be panic in the streets about the fact that our brain cells are eating themselves. There are plenty of other places in the body where autophagy takes place in lean times to conserve energy --still, scientists had thought the brain was pretty resistant to this.
The main lesson, the authors say, is the potential for new drug development. And given how hard scientists are finding it to come up with effective anti-obesity medications, that’d be welcome.