Medicine Nobel Prize awarded to Sleep (Circadian Rhythm) Researchers
The Nobel Prize for Medicine was awarded to three sleep researchers this week (2017). They are Jeffrey Hall and Michael Rosbash of Brandeis University in Boston, and Michael Young of Rockefeller University in New York. They have discovered the genetic secrets behind the body’s circadian (or around the day, 24-hour) rhythm.
All multicellular organisms seem to have a circadian rhythm. It governs eating and sleeping behavior, other behaviors, body temperature, hormone levels, energy levels and alertness. It is closely synchronized with the 24-hour day. These researchers discovered how the body maintains this 24-hour alignment.
The period gene produces the PER protein, which builds up during the night. The timeless gene produced TIM protein. PER combines with TIM protein. The combination crosses into the cell nucleus and suppresses activity of the period gene. During the day the period gene is suppressed, and there is less PER produced. Eventually there is not enough PER to suppress the period gene, and at night PER is produced again. This to and fro of PER forms a clock, an oscillation that maintains the circadian rhythm. The DBT protein produced by the doubletime gene delays the build-up of PER. This helps to keep the oscillatory clock at 24 hours. Mutations in the period gene lead to problems in the circadian rhythm.
Circadian rhythm sleep disorders
Circadian rhythm sleep disorders include delayed sleep phase disorder, advanced sleep phase disorder, irregular sleep wake disorder, non-24 hour disorder, jet lag disorder, and shift work disorder.
People with delayed sleep phase want to go to sleep late and get up late, but cannot go to sleep or get up on time. This is a common disorder, especially in teenagers and young adults. People with advanced sleep phase disorder want to go to bed early and get up early. This is uncommon, and found in the elderly. People with irregular sleep wake disorder sleep in many short irregular bouts through the day. This tends to occur in nursing homes and institutions. Non-24 hour disorder is very rare, and tends to be found only in completely blind people with no light sensitivity. They tend to go to bed and get up an hour or so later each day.
Jet lag disorder occurs when people travel across multiple time zones. Shift work disorder is common and occurs when the shift worker is not able to align the circadian rhythm to the required work rhythm.
Melatonin and bright light at carefully selected times and useful in treating circadian rhythm sleep disorders.