Chemical switch for body’s internal clock identified

18 December, 2007

The chemical switch that controls the genetic mechanism regulating people’s internal body clocks has been identified.

Researchers at the University of California, Irvine, the United States, say that though the process involves complex genes, the whole mechanism is controlled by a single amino acid, which is a building block of protein.

The finding might lead to a new pharmaceutical approach to sleep disorder treatments – more effective drugs to treat sleep disorders and related ailments.

The findings could also lead to treatments for jet lag and other serious sleep disorders, and result in drugs being developed for those working night shifts to adjust to their peculiar hours.

Body clocks – or, circadian rhythms – control factors such as when we feel hungry or tired, the body’s temperature and the ebb and flow of hormones.

The internal cycle is usually more than 24 hours and so has to be reset every day. Or else, people would go to bed later and later. Normally sunlight or breakfast help to start the body’s internal clock.

In the study, published in the journal Nature, Professor Paolo Sassone-Corsi, lead researcher, said, “Because the triggering action is so specific, it appears to be a perfect target for compounds that could regulate this activity. It is always amazing to see how molecular control is so precise in biology.”

The body’s internal clock, a highly sensitive mechanism able to anticipate changes in the environment, regulates a number of body functions, ranging from sleep patterns to metabolism and behavior.

Circadian rhythms regulate up to 15% of all human genes. Disruption of these rhythms can cause insomnia, depression, heart disease, cancer, and neurodegenerative disorders.

The latest study found that a single amino acid in a protein produced by BMAL1 undergoes a modification that triggers the genetic chain of events involved with setting the body’s rhythms.

If this modification does not work, the switching mechanism can be thrown off, derailing the whole system.

The researchers are currently testing antibodies that can target the activity of the amino acid that controls the circadian rhythms.

BBC quoted Dr Neil Stanley, a sleep expert at Norwich University Hospital, the United Kingdom, as saying that 89 different types of sleep disorder had so far been classified, but all sleep medications – hypnotics – currently targeted the same neurotransmitter called GABA.

Dr Neil Stanley added, “People’s sleep problems tend to be very individual, but a new target may allow us to develop more specific treatments and to offer patients more personalized care.”

Sleep disruption is increasingly causing serious health problems. In November 2007, a WHO report linked the risk of prostate and breast cancer to working abnormal hours.

Immune systems of night workers are also weak and can increase vulnerability to infections.