Serotonin crucial to development

It's long been known that the period right after birth is critical in the developmental process. While postnatal development has been examined in the past, links to specific critical systems have yet to be well established. A recent study may shed some light on exactly why this is the case, as well as what are the critical systems during development, at least in terms of mental health.

Researcher at Columbia University found that there is a messenger protein, a signaling molecule, which is critical in the development of emotional behavior. The research, which was conducted on mice, found that when these mice lacked the protein in the frontal brain during the critical development period, they failed to react normally upon encountering stressful situations.

However, when the protein was disabled during adulthood, there were no noticeable effects. The protein was found to be a serotonin receptor.

According to Dr. Rene Hen of Columbia University, lead author of the study, "our results suggest that normal anxiety-like behavior in the adult requires proper signaling by serotonin via forebrain ... receptors during the early postnatal period."

Dr. Solomon Snyder of the Department of Neuroscience at Johns Hopkins Medical School added supportively, "it seems possible that interference in serotonin systems during embryonic life could affect anxiety development after birth."

Researcher found that the serotonin-deficient mice were reluctant to move around in open space, would not enter elevated mazes and were generally slow to adapt to new environments, as compared to a control mouse population.

The study, published in Nature, found that only the front part of the brain was involved in developing this behavior, and the critical period for developing normal anxiety-like behavior in mice occurs in the period between five to 21 days after birth.

It is important to note that there exists key difference between mice and men during the development period. The point at which a rodent is born is comparable to between 5 and six months during the gestation period for a human fetus. Due to this fact, the translation of the rodent results to human should be taken with a grain of salt.

Still, serotonin's role as a mood regulator has long been known. Drugs that reduce serotonin levels cause depression while those that replenish serotonin levels have the opposite effect.

"Serotonin ... has been implicated in many aspects of brain function and in the effects of many important drugs that are used to treat anxiety, depression, migraine, headaches, nausea, pain and irritable bowel syndrome," according to Dr. Snyder.

"That anxiety is linked to the need or serotonin receptors in a specific brain region, at a particular period of development adds a new layer of understanding of serotonin's function," Snyder added.

Dr. Hen adds her views on the research, "Presumably stimulation of the receptor during this period is essential to set in motion a cascade of events which leads to long-lasting changes in brain chemistry or structure that are essential for normal anxiety-like behavior throughout life."

As a final statement the authors of the paper said, "Serotonin stimulation of the forebrain receptor during this period likely triggers long lasting changes in brain chemistry or structure that are essential for normal emotional behavior throughout life.