Scientists have identified what makes us feel crappy and unmotivated when we’re sick… and they’ve got some ideas for drugs to make it go away.
Being lethargic and not feeling so great is related to a particular signaling system that regulates sleep.
That’s especially cool because this neurotransmitter induces sleep… and now it’s also found to be important in maintaining motivation and movement during illnesses.
“We all know what it means to feel ‘bad’ when we’re acutely ill,” says study researcher Daniel Marks of the Oregon Health and Science University. In particular, patients with chronic diseases experience a compromise in motivated behaviors. “They don’t feel like getting up and doing anything. Yet the brain mechanisms behind this common experience have remained obscure.”
In response to illness, animals divert all their energy to fight infection. Lethargy, fever, and loss of appetite are generally symptoms of the body’s highly organized strategy to sacrifice biological and physiological priorities to provide the greatest chance of survival.
So, Marks and colleagues studied rat brains. Watch their video of a sleepy, sick rat.
- They saw that lethargy is brought about by inflammation-sensitive neurons near the neurotransmitters that control physical activity and arousal. This is called the orexin system.
- They injected the rats with orexin signaling. That totally restored their motivated behaviors and movement. And here’s a video of a restored rat. (Watch it explore!)
Since chronic disruption of this neurotransmitter system leads to sleep disturbance and loss of motivated behaviors, the researchers propose that drugs that mimic orexin would improve quality of life and independent living for chronically ill patients.
And because the role of orexin in sleep disorders has been known for several years, narcolepsy drugs might be able to restore energy by reversing the inactivity and exhaustion you feel when you’re sick.
That also means that a treatment is nearly ready for clinical application.
Images: rat sleeping at Petco by J. Fang, sleep by kevinrosseel