Enzyme behind baby blues found

Other than loss of oestrogen, an increase in levels of enzyme, called monoamine oxidase A (MAO-A) in the female brain after giving birth, is what causes baby blues or postpartum depression.

It is known that in the first three to four days after giving birth, oestrogen levels drop 100 to 1000 fold.

In the current study, led by Julia Sacher from the MPI for Human Cognitive and Brain Sciences in Leipzig, it was discovered that proportional to this oestrogen-loss, levels of MAO-A increase dramatically throughout the female brain.

The enzyme can be found in higher concentrations in glial cells and monoamine-releasing neurons, where it breaks down the neurotransmitters serotonin, dopamine, and norepinephrine.

Other than being responsible for transmitting signals between nerve cells, these neurotransmitters also influence our mood.

If they are deficient, we initially feel sad, and later have a high risk of becoming depressed.

Using positron emission tomography (PET) - an imaging method that creates images of the distribution of a short-lived radioactive substance in an organism - the researchers measured the distribution of a radioactively- marked ligand in the brain which binds specifically and with a high affinity to the enzyme monoamine oxidase A.

They found that levels of MAO-A were, on average, 43 percent higher in women who had just had a baby than in a control group consisting of women who either had children a long time ago or had no children.

The MAO-A increase could be shown in all brain regions investigated, with MAO-A levels being highest on day five postpartum.

This result coincides neatly with the fact that the mood of mothers often hits a low precisely on this day.

Severe baby blues symptoms can be viewed as a prodromal stage for postpartum depression.

From this perspective, preventing depressive symptoms in the immediate postpartum period may have powerful impact for prophylaxis of postpartum depression.

Attempts can be made to either lower elevated levels of MAO-A with selected antagonist drugs, or to increase the concentration of monoamine neurotransmitters that can elevate mood.

Both have the goal of keeping levels of monoamine neurotransmitters in the brain balanced after birth.

To develop treatments that are compatible with breastfeeding, the intake of dietary supplements of monoamine precursors in the early postpartum period would be a promising strategy to maintain a sufficient balance of monoamines during this time.

This includes the administration of precursor supplements such as the amino acids tryptophan and tyrosine, which the body can convert into the neurotransmitters serotonin, norepinephrine, and dopamine, respectively.

"Our results have the exciting potential for prevention for severe postpartum blues. This could have an impact on prevention and treatment of postpartum depression in the future", said Sacher, first author of the study.