Serotonin levels in the brainstem of infants may be linked to cot death.
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SYDNEY: Low levels of the mood-regulating brain chemical serotonin may be a cause of Sudden Infant Death Syndrome (SIDS) or cot death, scientists said.
The findings may one day lead to a blood or tissue serotonin test which could identify infants at a higher risk of suffering from SIDS, the researchers say, allowing precautionary measures to be put in place to protect the most vulnerable.
Researchers at Children's Hospital Boston measured the levels of serotonin and tryptophan hydroxylase, the enzyme that helps make the key neurotransmitter, in the brainstem of 36 infants who died from SIDS and two control groups - babies who died suddenly of other causes and infants who were hospitalized with chronic oxygenation problems.
Problems in the brainstem
"Serotonin levels were 26% lower in SIDS cases compared with age-adjusted controls," the researchers wrote in their study in The Journal of the American Medical Association. Tryptophan hydroxylase levels were 22% lower than in the control groups.
The researchers also found that SIDS babies had fewer serotonin receptors in the brainstem.
The connection between SIDS and problems in the infants' brainstems was already well established, but this new study points to a possible problem in the brainstem that causes SIDS.
"The receptors are what serotonin interacts with to produce an effect," David Paterson, one of the authors of the study.
Breathing challenges amplified by low serotonin
"In SIDS cases, in the brainstem, they actually have fewer of these receptors, and if there's a lower number of receptors, that's usually an indication that there's something wrong with serotonin," he said.
The measurements were taken from the medulla, a part of the brain stem that helps to regulate basic functions such as body temperature control and breathing.
Serotonin abnormalities may reduce an infant's ability to cope with breathing challenges, such as low oxygen or high carbon dioxide levels, said lead researcher Hannah C. Kinney of Harvard Medical School.
