Brain molecule may hold jet lag cure
Washington: VIP treatment! Boosting a brain chemical may lead to new treatments for jet lag, scientists say.
The molecule called vasoactive intestinal polypeptide (VIP) desynchronises the cells in the biological clock to help the body adjust more quickly to abrupt shifts in daily light/dark schedules such as those that plague modern life.
The molecule has the startling effect of desynchronising the cells at higher dosages, said researchers from the Washington University in St Louis.
Neurons knocked for a loop by a burst of VIP are better able to re-synchronise to abrupt shifts in the light-dark cycle such as those that make jet lag or shift work so miserable, researchers said.
It takes tumbling cells only half as long as undisturbed cells to entrain to the new schedule, scientists said.
The scientists hope to find a way to coax the brain into releasing its own stores of VIP or to find other ways to deliberately cause tumbling so the body's clock will reset to a new time.
Such a treatment might help travellers, shift works and others who overtax the biological clock's ability to entrain to environmental cues.
The finding is the latest to emerge from the lab of Erik Herzog, who has studied the body's time-keeping mechanisms for 13 years.
The master circadian clock in mammals is a knot of 20,000 nerve cells roughly the size of a quarter of a grain of rice called the suprachiasmatic nucleus (SCN).
Each neuron in the SCN keeps time, but because they're different cells, they have slightly different rhythms. Some run a bit fast and others a bit slow.
"They're like a society where each cell has its own opinion on what time of day it is. They need to agree on the time of day in order to coordinate daily rhythms in alertness and metabolism," said Herzog.
The cells talk to one another through a molecule called VIP, a small string of amino acids that they release and receive.
It's through VIP that cells tell one another what time they think it is, Herzog said. If you get rid of VIP or the receptor for VIP, the cells lose synchrony.
"We were trying to understand exactly when VIP is released and how it synchronised the cells," Herzog said, "and Sungwon An, then a graduate student in my lab, discovered that when there was extra VIP around, the cells lost synchrony."
The study was published in the journal Proceedings of the National Academy of Sciences.