Fixing Broken Biological Clocks

• Published in: American scientist Vol. 109; no. 5; pp. 262 - 264
• Main Author: Burke, Katie
• Format: Journal Article
• Language: English
• Published: Research Triangle Park Sigma XI-The Scientific Research Society 01-09-2021
• Subjects: Adenosine; Adenosine triphosphate; ATP; Biological clocks; Biologists; Blindness; Brain research; Caffeine; Circadian rhythm; Circadian rhythms; Exposure; Light; Molecular modelling; Sleep; Sleep and wakefulness; Sleep deprivation; Sleepiness
• ISSN: 0003-0996; 1545-2786
• DOI: 10.1511/2021.109.5.262

At one point or another, we've all hit the wall of sleep: the point when you are so exhausted that you cannot stay awake, no matter how bright it is outside or how much caffeine you have consumed. Until recently, though, no one understood the exact molecular mechanisms responsible for this ubiquitous experience. Circadian biologists have long been aware that exposure to light can shift a mammal's sleep-wake cycle, but they haven't been able to work out why light exposure becomes ineffectual when an animal is sleep-deprived. Sleep researchers have also known that caffeine delays sleep by blocking the action of a molecule called adenosine. As an animal uses energy while it is awake, adenosine builds up in the body--for example, through the breakdown of a key metabolic molecule, adenosine triphosphate (ATP)--and induces a sense of sleepiness. But until recently, no one had determined how adenosine made that happen. A study published in Nature Communications, led by neuroscientist Aarti Jagannath, circadian biologist Russell Foster, and pharmacologist Sridhar Vasudevan, all at Oxford University, marks a major advance in untangling the roles of adenosine and light in sleep.