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Orexin Receptor Blocker: 

  • Suvorexant/Belsomra

UT Southwestern has been home to many of the world’s top sleep researchers, including those who discovered a protein called orexin and related cell receptors involved in both wakefulness and appetite. Researchers in Dr. Masashi Yanagisawa's lab at UT Southwestern authored a landmark paper in 1998 that described two orexin receptors – OX1R and OX2R – that proved the key to wake-sleep cycles. The discoveries were made in part by studying individuals with narcolepsy, a disorder in which patients have low levels of orexin and have difficulty staying alert.

The findings allowed development of a new class of sleep aid medicine called orexin receptor antagonists. Orexin is a chemical produced in the brain that sends messages to keep people awake. When blocked, it allows people to sleep. Suvorexant was the first drug of its kind to be approved by the FDA to block orexin, providing a new treatment for insomnia. Researchers found that, unlike traditional sleep aides, which target broader systems and can lose effectiveness over time and lead to addiction, suvorexant impacts more localized systems and causes fewer side effects, such as dizziness. 

UT Southwestern’s Chair of Neuroscience, Dr. Joseph Takahashi, further contributed to the understanding of sleep and appetite impacts of orexin when he found ties between mutations in the CLOCK gene, a regulator of sleep-wake cycles, and depressed levels of orexin that impacted metabolism, appetite, and energy.

Photos: Dr. Masashi Yanagisawa (left) and Dr. Joseph Takahashi