This drug is better known as an antidepressant. But Prozac has been found by a new study published in the journal Science to restore old brain cells to a more plastic youthful stage.

"The work raises the distant prospect that it could be used to treat other conditions caused by malfunction of brain cells. One of them is amblyopia, the 'lazy eye' condition in which one eye is weaker than the other, because it was not used enough in early childhood. All this needs to be validated in animal models," said lead author Jose Fernando Maya Vetencourt, a researcher in neurobiology at the Scuola Normale Superiore in Pisa, Italy.

Amblyopia could be a possible target of Prozac because the tests targeted visual neurons (brain cells). The team served regular doses of Prozac to adult rats with impaired vision due to the lack of exposure to visual stimuli at a critical point in their early development. The researchers detected changes in brain protein activity and electrical signaling resembling that of younger neurons, and vision recovery in the rats.

"Future experiments will try to determine whether the same treatment will have a similar effect on brain cells governing functions other than vision," said Vetencourt.

Prozac is a selective serotonin reuptake inhibitor (SSRIs), and part of a category of drugs blocking serotonin, a neurotransmitter. Most antidepressants impact brain chemistry, like MAO inhibitors.

"There have been discussions about the theory that a cause of depression is lack of growth in the brain. It used to be thought that no change could occur in the adult brain. New research has shown that there can be new growth in the brain, so the theory is that depression is caused by lack of new growth. [The new study] supports the idea that antidepressants act because they promote growth in the brain." said Dr Julio Licinio, chairman of psychiatry at the University of Miami Miller School of Medicine.