We all know the dangers of sleep apnea. The exhaustion from not sleeping properly can impact driving, job performance, concentration, and so much more. It also has a physical impact on our bodies as shown with our blood pressure, as well as heart and brain function. This potentially deadly sleep disorder is no joke and scientists know it. Research in the field of sleep apnea has increased exponentially in recent years. Every new study yields more information on how we can combat the dangerous disorder. Now, we are begining to understand the relationship between sleep apnea and serotonin activity.
One of the scariest things about sleep apnea is that it can affect anyone of any age, including infants. New parents have enough to worry about without the dark cloud of Sudden Infant Death Syndrome hanging over their heads. However, SIDS is still the leading cause of death for U.S. infants between the ages of one and twelve months of age.
Researchers have turned their attention to serotonin neurotransmitters and the cells that produce them. Previous studies have indicated that the serotonin-producing neurons directly influence breathing. Samples from infants who’ve died as a result of SIDS also show abnormalities in serotonin-producing neurons. This link prompted a new study to examine the relationship between the neurons and SIDS.
The study focused on the idea that the neurons that produce serotonin may directly contribute to SIDS deaths. Studying mice, the findings indicate that a loss of normal serotonin-producing nerve cell activity actually diminishes the body’s ability to recover when there’s a breathing interruption. According to News Medical:
“If we can determine whether serotonin-producing neurons play an active and necessary role in regulating breathing, heart rate, and the recovery response to apneas in young mouse pups, it could provide a plausible biological explanation for at least some SIDS cases,” said Susan Dymecki, professor of genetics at Harvard Medical School and senior author of the study.
“This possible explanation might provide some hope, even if minutely, for the profound grief experienced by families who have lost a child to SIDS, and may one day help researchers prevent SIDS altogether,” she said.
When working properly, the brain, heart, and lungs work together to create a continuous flow of air. They bring oxygen into the body while expelling carbon dioxide. With disorders like sleep apnea, breathing stops temporarily. This causes oxygen levels to dip while carbon dioxide levels rise. In order to restore healthy levels of the two, the brain triggers a response. This response usually results in a gasp for air and increased heart rate, also known as autoresuscitation.
Unfortunately, this life saving reflex doesn’t always kick in. When it doesn’t, the result can be deadly. The study explores the role of the serotonin-producing neurons in relation to autoresuscitation in week-old mice. The mice were genetically modified to cause their serotonin neurons to be inhibited in response to an injected chemical. Only serotonin neurons were impacted by the test. Sleep apnea was then induced.
The mice with inhibited serotonin neurons had greater instances of sudden death and weaker breathing recovery after apnea episodes when compared to the unmodified mice. This indicates that properly functioning serotonin neurons are vital from birth. Decreased serotonin activity and sleep apnea can be a deadly combination.
Despite the impairment, the genetically altered mice heart rates recovered normally, even after breathing impairment. The study goes on to state:
“This uncoupling of the breathing and heart-rate recover responses was unexpected,” said Dymecki. “It suggests that these two vital physiological responses—heart rate and breathing—could be more separable at the level of brain cells and circuits than previously anticipated, despite their interwoven physiology.”
Additional studies will help us understand if the same principles also affect humans. As it stands, findings support the concept that defects in serotonin neurons can make infants more vulnerable to SIDS and other apneas and health challenges. If this can be replicated in human studies then the results of the study may help create and improve screening tools to determine which infants are high-risk for SIDS. The study may also help when it comes to treating the problem.
It also raises the question about adults and their relationship between serotonin activity and sleep apnea. The best course of action is to treat the disorder head on using oral appliances or other devices to help keep the airway open. While science works to find a solution, sleep apnea experts like Mark Levy DDS dedicate their lives to helping those who suffer from the dangerous disorder.