Researchers who had bred a group of mice in hopes of learning more about a brain hormone that stimulates appetite got a bit of a surprise when they saw that the rodents would suddenly collapse and fall fast asleep with no provocation. As a result, Howard Hughes Medical Institute investigator Masashi Yanagisawa and colleagues at the University of Texas’ Southwestern Medical Center in Dallas have an exciting new lead into the genesis of sleep and the origins of narcolepsy, a severe sleep disorder in humans.
In 1998, Yanagisawa discovered the orexins, small brain proteins and their receptors that regulate feeding behavior in mice. To probe the role that orexins play in regulating appetite, Yanagisawa and his colleagues developed a strain of knockout mice whose orexin genes do not function properly.
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