Antidepressants boost brain growth

Reported by Susan Aldridge, PhD, medical journalist

Animal work has shown that two popular antidepressants can boost the growth of brain cell fibers.
The axon is the fiber which carries nerve impulses between brain cells. Researchers at Johns Hopkins University now unveil new work revealing how the antidepressants fluoxetine and tianeptine can boost the growth of axons in animals. The experiments showed that the two selective serotonin reuptake inhibitors (SSRIs) increase axon density in the frontal and parietal lobes of the brain and in the limbic area - all of which control the sense of smell, emotion and motivation and may play a role in depression.

The SSRIs have traditionally been thought to work by increasing levels of a brain chemical called serotonin in the gaps between nerve cells called synapses. The axon carries electrochemical impulses to the synapses where serotonin and other chemical messengers are released. What has never been explained before is why the benefits of antidepressants take so long to kick in - typically up to four weeks. It may be that the growth of the axons take this long and is the mechanism by which serotonin levels are increased.

Source
Journal of Neurochemistry January 2006

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