Experiments with the brain stems from mice showed the researchers the net result of what happens when the brain's level of oxygen is depleted and the levels of the hormone serotonin are disturbed in so-called pacemaker cells. These cells are a specific group of neurons responsible for gasping.
These cells are needed to reset a normal breathing pattern in sleeping babies. Normal serotonin levels are needed for these respiratory pacemakers to induce gasping. But in case of the infants with SIDS they have disturbed levels of serotonin. The findings were published in the Journal of Neuroscience.
Ramirez said that when there is lack of oxygen the respiratory network is shut down. Gasping is the only chance to wake up. But kids with SIDS gasp only one or two times and they don't wake up. This is because the nerve cells required for gasping need serotonin.
In their experiments, Ramirez's team found that when they took serotonin away from these pacemaker cells, the gasping decreased from about 20 gasps to two or three not enough for the baby to wake up. He said that by identifying the mechanism of gasping new methods of screening and treating infants at risk for SIDS would be developed. He also said that the presence of nicotine changes the functioning of these cells.
Altered serotonin levels may lead to the development of other problems such as depression, bipolar disorder or attention-deficit disorder. Betty McEntire, executive director of the American SIDS Institute said that the study would help to understand the root of the defect.
Dr. George B. Richerson, a professor of neurology, cellular and molecular physiology at Yale University said that breathing rhythms and the ability to gasp are developed in infants in the womb but this study helps in the identification of the cause of SIDS.
