Abstract
Fundamental questions about sleep and its universal existence remain elusive. The common presence of sleep across phyla suggests that it must serve some indispensable cellular and/or molecular function needed for survival. Micro-array studies, performed in several model systems, have identified classes of genes that are believed to regulate sleep-state or vice-versa. This has led to the following concepts: first, a function of sleep is to maintain synaptic homeostasis; second, sleep is a stage of macromolecule biosynthesis which is needed during the waking period; third, extending wakefulness leads to the down regulation of several important metabolic pathways which needs to be balanced for extended survival; and, fourth, extending wakefulness leads to endoplasmic reticulum stress. In human sleep studies, micro-arrays are being pragmatic to the identification of bio-markers for sleepiness and for the common sleep disorders. This study tries to find out the correlative processes which happen across different tissue system in the maintenance of sleep. We compared the gene expression profile in brain and liver due to REM sleep deprivation. Our result suggests that sleep deprivation affects a different set of genes in the brain and liver.