Genes that regulate how much we dream

EurekAlert: Sleep is known to allow animals to re-energize themselves and consolidate memories. Rapid eye movement (REM) sleep, a mysterious stage of sleep in which animals dream, is known to play an important role in maintaining a healthy mental and physical life, but the molecular mechanisms behind this state are barely understood.
Now, an international research team led by researchers at the RIKEN Center for Biosystems Dynamics Research (BDR) in Japan has identified a pair of genes that regulate how much REM and non-REM sleep an animal experiences.
Sleep is a universal and vital behavior in animals. In higher vertebrates such as mammals and birds, sleep is classified into two phases, rapid eye movement (REM) sleep and non-REM sleep. During REM sleep, our brain is as active as it is during wakefulness, and this stage is believed to function in memory consolidation.
Although our knowledge of the neural mechanisms underlying sleep has gradually advanced, the essential molecular factors that regulate REM sleep are still unknown.
Now, however, a research team led by Hiroki Ueda at RIKEN BDR and The University of Tokyo has identified two essential genes involved in the regulation of REM sleep.
The amount of REM sleep was drastically decreased down to almost undetectable levels when both genes were knocked out in a mouse model. This study was published by Cell Reports on August 28.
Several past studies have suggested that acetylcholine–the first identified neurotransmitter–and its receptor are important for the regulation of REM sleep.
Acetylcholine is abundantly released in some parts of mammalian brain during REM sleep and wakefulness.
However, it was unclear which receptor or receptors were directly involved in the regulation of REM sleep due to the complexity of the underlying neural network.