Summary: Researchers have discovered how the brain controls our breathing in response to changes in blood oxygen and carbon dioxide levels.Source: eLife.
Scientists at the Karolinska Institutet in Sweden have discovered how the brain controls our breathing in response to changes in blood oxygen and carbon dioxide levels.
Breathing control is essential to life. Without an adequate response to rising carbon dioxide levels, people can suffer from respiratory problems, illness and panic. In the worst cases, this can lead to premature death, as in the case of Sudden Infant Death Syndrome.
There's been a debate about how the brain controls breathing. Now, a new study in mice, to be published in the journal eLife, shows that when exposed to decreased oxygen or increased levels of carbon dioxide, the brain releases a small molecule called Prostaglandin E2 (PGE2) to help protect itself and regulate breathing.
To discover this mechanism, researchers have grown a section of a mouse brain stem (the central part of the brain). The section contained an arrangement of nerve and support cells that allowed it to «breathe» for three weeks. During this time, the team monitored the cells and their behaviour in response to changes in the environment.
«We've seen that exposure to different substances causes the brain stem to breathe faster or slower. Perhaps most interesting was its response to carbon dioxide, which triggered a release of PGE2. Here, PGE2 acted as a signalling molecule that increased respiratory activity in the carbon dioxide-sensitive region of the brain stem, leading to slower and deeper breaths, or «sighs» », explains David Forsberg, PhD student and first author of the study.
These new insights have important implications for babies, who experience significantly reduced oxygen levels during birth. At this stage, PGE2 protects the brain and prepares the brain stem to generate deep breaths similar to sighs, leading to the first breaths of air after birth.
The study also reveals a new pathway linking the inflammatory and respiratory systems . La . PGE2 is also released during inflammation and fever, which can disrupt breathing patterns and interfere with normal responses to carbon dioxide. This in turn can lead to disturbed and even dangerous respiratory arrest.
«Our results provide some insight into how and why our respiratory responses to unbalanced levels of oxygen and carbon dioxide are altered during infectious episodes. It also helps to better understand why infection can inhibit breathing so severely in newborns,»says Eric Herlenius, professor in the Department of Women's and Children's Health at Karolinska Institutet, and lead author of the article.
«Now we want to find out how the breaths form and develop during inflammatory episodes. This could be useful in looking for potential new ways to save babies' lives when they are unable to catch their breath. »
Source: eLife. “New Brainstem Model Reveals How the Brain Controls Breathing.” NeuroscienceNews. NeuroscienceNews, 5 July 2016.