A 'Sandman' Molecule Could Reveal Why Do We Need To Sleep

Admin | Published 2016-08-09 14:06
  Think about precious hours you've wasted in your bed sleeping. It sounds disturbing that you've spent almost 1/3 of your life sleeping. According to Gero Miesenböck, a neuroscientist at the University of Oxford, every animal with a brain sleeps and obviously it bears considerable risks. While they are sleeping, animals are extremely vulnerable to attacks, with no obvious benefit to make up for it — at best. "If evolution had managed to invent an animal that doesn’t need to sleep ... the selective advantage for it would be immense. The fact that no such animal exists indicates that sleep is really vital, but we don't know why." Miesenböck said for Washington Post. [embed]https://www.youtube.com/watch?v=pwNMvUXTgDY[/embed] A team of sleep of researchers, whose member is Miesenböck, believe they are on a track of solving the mystery of sleep. In a statement published in Nature, they describe a cluster of two dozen brain cells in fruit flies that operate as a homeostatic sleep switch, turning on when the body needs rest and off again when it's time to wake up. If you are one of these people (like we are) who will be like: "Duh, bro, we sleep, 'cause we get tired, do you really need scientific research to tell the obvious?", than Mr. Miesenböck has can give you puzzling answer telling that we don't even know what tired is. Scientists know that sleep is controlled by two systems. There's the circadian rhythm, which monitors external cues like sunlight and temperature to identify the right time to go to bed. This is how animals can ensure that their body clock is synchronized with the world around them. Then there's the sleep homeostat, the mysterious mechanism that monitors internal cues. Something — we're not sure what — builds up in the body over the course of the day. When it hits a certain ceiling, the sleep control neurons spring into action and we start to snooze. Meanwhile, whatever chemical signal the homeostat is monitoring is cleared away. When the levels are low enough, the neurons turn off, and we awaken. Researchers were examining fruit flies (you can see their work here), and what they've found is that electrical activity in a cluster of cells called the dorsal fan-shaped body (dFB) was correlated with sleep.

Thank you, little fruit fly. You will be remembered!

They successfully proved that there is the direct link between the dFB neurons and sleep — that this center really was the "switch". Examining the mechanism more closely, they zeroed in on one ion channel — a molecular gateway that allows electrical signals to flow between brain cells — that seemed vital to this whole process. When the flies were sleeping, the molecule stayed inactive at the centers of neurons. But when dopamine was released, it moved to the cell's exterior, causing the entire dFB complex to short circuit and waking the fruit flies up. The scientists were also able to turn the ion channel off entirely. Those unfortunate flies descended into an endless sleep from which they couldn't wake themselves up. These scientists called the ion channel "Sandman", after the mythical character who puts people to sleep and brings them dreams. [embed]https://www.youtube.com/watch?v=CX45pYvxDiA[/embed]   Miesenböck says that the ability to monitor and manipulate the sleep homeostat at the molecular level opens up a bunch of new opportunities for sleep researchers. For example, scientists have long known that depriving animals of sleep can kill them. If Miesenböck and his team are able to figure out what the homeostat responds to, they would probably be a big step closer to understanding the biological function of sleep. source - https://www.washingtonpost.com  
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