According to a study published in the journal PLoS Biology, dopamine, a neurotransmitter that helps controls the brain’s reward and pleasure centers, also plays a role in sleep regulation.
The study was conducted by researchers from CIBERNED (Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas), dependant on the Spanish Ministry of Economy and Competitiveness through the Carlos III Health Institute, and from the Faculty of Biology of the University of Barcelona.
Dopamine is produced in the pineal gland. This gland regulates our internal clock (circadian rhythm) by releasing melatonin at night which helps regulate the body’s metabolic activity during sleep.
Another hormone, called norepinephrine, is involved in circadian rhythm and the release of melatonin in the pineal gland. The functions of norepinephrine are carried out via attaching to its receptors in the membranes of cells.
For years, researchers believed that all norepinephrine receptors acted independently of other proteins. However, in this study the team found that these receptors actually work together with other dopamine receptors forming ‘heteromers’.
When dopamine interacts with its receptors it stops the effects of norepinephrine, leading to lower production and release of melatonin. In addition, the team discovered that these dopamine receptors only appear in the pineal gland towards the end of the night.
According to the researchers, the formation of these heteromers signal the brain to “wake up” by inhibiting melatonin production.
Dr McCormick said:
“These results are interesting as they demonstrate a mechanism in which dopamine, normally increased at times of stimulated, can directly inhibit production and release of a molecule, melatonin, that induces drowsiness and prepares the body for sleep.”
The researchers stated that these findings could help them to design new treatments to help mitigate circadian rhythm disturbances, such as sleep disorders, those associated to jet lag, and those found among people who work night shifts.
40% of the world’s population suffer from sleep disorders, according to the World Health Organization. Furthermore, disturbances in circadian rhythm can also change body mass index, and cause behavioral disorders.
Written By Grace Rattue