Submitted via IRC for Bytram
Serotonin is a multipurpose molecule found throughout the brain, playing a role in memory, cognition, and feelings of happiness and other emotions. In particular, researchers have long debated serotonin's role in sleep: Does serotonin promote sleep, or its opposite, wakefulness?
Now, Caltech scientists have found that serotonin is necessary for sleep in zebrafish and mouse models.
A paper describing the research appears online on June 24 in the journal Neuron. The work is a collaboration between the Caltech laboratories of David Prober, professor of biology and affiliated faculty member of the Tianqiao and Chrissy Chen Institute for Neuroscience at Caltech; and Viviana Gradinaru (BS '05), professor of neuroscience and biological engineering, Heritage Medical Research Institute Investigator, and director of the Chen Institute's Center for Molecular and Cellular Neuroscience.
Previous studies on serotonin and sleep have yielded conflicting results. Some research showed that serotonin promotes sleep, but other work showed that serotonin-producing neurons were most active and releasing the chemical during wakefulness.
In order to settle this debate, the Caltech team focused on a region called the raphe nuclei, which has the brain's main population of serotonin-producing (or serotonergic) neurons. The raphe are evolutionarily ancient structures found in the brain stem of a wide range of organisms from fish to humans, and they are responsible for both manufacturing and sending out serotonin to other brain regions.
[...] "The theory is that, in order to sleep, you need to have high sleep pressure and the circadian clock needs to be aligned with the time of day -- nighttime for diurnal creatures like us and daytime for nocturnal animals."
The researchers theorize that the firing of neurons in the raphe and their release of serotonin is a way for the brain to build up sleep pressure. Indeed, they found that zebrafish lacking serotonin as well as mice with ablated raphe show reduced sleep pressure.
While the studies were in animal models, the raphe region and its production of serotonin are similar in human brains. The research can contribute to explanations of some sleep-related side effects of common antidepressant drugs that increase serotonin levels in the brain.
Grigorios Oikonomou, Michael Altermatt, Rong-wei Zhang, Gerard M. Coughlin, Christin Montz, Viviana Gradinaru, David A. Prober. The Serotonergic Raphe Promote Sleep in Zebrafish and Mice. Neuron, 2019; DOI: 10.1016/j.neuron.2019.05.038
(Score: 0) by Anonymous Coward on Wednesday June 26 2019, @01:37AM
Large studies are just brute force. Newton figured out gravity using 9 planets and an apple.