Study shows molecular basis of crib death

MONTEROTONDO, Italy, July 3 (UPI) -- Researchers in Italy say an imbalance of the neuronal signal serotonin in the brain stem may help explain Sudden Infant Death Syndrome.

A team at the European Molecular Biology Laboratory in Monterotondo, Italy, said the brain stem, the lower part of the brain that forms the link to the spinal cord, coordinates many fundamental functions, including control over cardiovascular and respiratory systems.

Cornelius Gross and his group modified the serotonin system of mice to understand the role of this signaling molecule in the brain stem. They over-expressed an important receptor that regulates serotonin signaling, called serotonin 1A autoreceptor.

"At first sight the mice were normal. But then they suffered sporadic and unpredictable drops in heart rate and body temperature," Gross says in a statement. "More than half of the mice eventually died of these crises during a restricted period of early life. It was at that point that we thought it might have something to do with SIDS."

The findings, published in the journal Science, says that deficits in serotonin signaling in the brain stem of the mouse can be sufficient to cause sudden death and strongly support the idea that a congenital serotonin defect could play a critical role in SIDS.