(Ivanhoe Newswire) -- Feeling tired? Well, according to new research, that sleepiness is all in your genes.

Researchers from the University of Kentucky in Lexington studied mice with different genetic make-ups that had previously been shown to have different responses to sleep deprivation. In the current study, mice were deprived of sleep and then allowed recovery sleep. Researchers found the expression of genes responsible for our 24-hour body clock increased the more the mice were kept awake and decreased when the mice were allowed recovery sleep. The finding supports the idea that these “clock genes” play an important role in the regulation of the need for shut-eye.
 

Researcher Bruce O’Hara, Ph.D., was quoted as saying, “We still do not know why we benefit from sleep, or why we feel tired when we are ‘lacking’ sleep, but it seems likely that sleep serves some basic biological function for the brain such as energy restoration for brain cells or memory consolidation. We have found that clock gene expression in the brain is highly correlated to the build-up of sleep debt, while previous findings have linked these genes to energy metabolism. Together, this supports the idea that one function of sleep is related to energy metabolism.”

The research shows in mice with the poorest quality of recovery sleep, the expression of some clock genes increased at a faster rate. Researchers report this suggests the complex changes in gene expression may underlie individual differences in sleep length and sleep quality. Researchers also note the changes in gene expression were seen throughout various regions in the brain -- adding to the theory that sleep is a global brain function.

Authors of the study conclude the research could provide clues to seasonal affective disorder and bipolar disorder, which are linked to both sleep and circadian rhythms.

SOURCE: BMC Neuroscience, published online Oct. 17, 2007