Possible connection to SIDS, preemie problems
A well-known chemical receptor in the brain associated with learning and memory probably also plays a key role in fetal development of the respiratory system, MIT researchers and colleagues will report in the May 1 Journal of Neuroscience.
The work indicates that "it would be prudent for pregnant women to avoid prolonged exposure to substances that affect the activity of this receptor," said Dr. Chi-Sang Poon, a Principal Research Scientist in the Harvard-MIT Division of Health Sciences and Technology (HST) and first author of the paper. Such substances include alcohol, PCP (angel dust), and some common anesthetic and analgesic drugs such as ketamine.
Mutant mice lacking the receptor "couldn't breathe or suckle well," said Dr. Poon, who noted that these symptoms are common in premature babies and are risk factors for Sudden Infant Death Syndrome. "Our study indicates a possible connection between abnormal receptor activity and problems in newborns," he said, although he stressed that more studies are needed to clarify this. Dr. Poon's coauthors are Zhongren Zhou, a former HST postdoctoral fellow, and Jean Champagnat of the Centre National de la Recherche Scientifique in France.
In a twist that took the researchers by surprise, they also found that a lack of this receptor led to high amounts of longterm synaptic depression (LTD), an activity linked to learning and memory. The kicker: the increased LTD was found in the brainstem, an area of the brain not usually associated with such "higher-level" functions.
"Conventional wisdom is that the brainstem coordinates lower behaviors like breathing and other vital functions, while the forebrain handles intelligence," Dr. Poon explained. "The discovery in the brainstem of activity associated with learning supports my argument that there's also a lot of intelligence going on beneath our conscious being."