Circadian clock found in cardiovascular system

LONDON US researchers have made important progress in understanding how circadian rhythms might be controlled in the cardiovascular system and other organs throughout the body. In the June 29 Cell, McNamara et al. revealed that blood vessels contain their own peripheral circadian system. The findings provided the first evidence that hormones and vitamins could regulate this clock's rhythm.

All eukaryotes display changes in biochemical or physiological behaviour that is governed by the day/night cycle, such as melatonin levels rising during the night and falling during the day. The master clock in humans is situated in the suprachiasmatic nucleus (SCN), an area of the brain which consists of a cluster of around 10,000 neurones synchronized to fire rhythmically, generating a co-ordinated circadian rhythmic output.

One of the most intensively researched areas of biology has focused on discovering the factors that drive these circadian rhythms. Studies have found interacting positive and negative ...