How Zebrafish Recover from Blinding Injuries.

• Position: STEM CELLS - Brief article

In zebrafish, decreased levels of the neurotransmitter gamma-amino-butyric acid (GABA) cue the retina, the light-sensing tissue in the back of the eye, to produce stem cells, reveal researchers at Vanderbilt University, Nashville, Tenn. The finding sheds light on how the zebrafish regenerates its retina after injury and informs efforts to restore vision in people who are blind.

For years, vision scientists have studied zebrafish to understand their retinal regenerative capacity. Zebrafish easily recover from retinal injuries that would blind a person permanently. Early studies led to the idea that dying retinal cells release signals that trigger support cells in the retina called Muller glia to dedifferentiate--return to a stem-like state--and proliferate.

However, recent studies in the mouse brain and pancreas suggest GABA, a well-characterized neurotransmitter, also might play an important role in regeneration distinct from its role in communicating local signals from one neuron to the next.

Scientists studying a part of the brain...