A small molecule restores light sensitivity to blind mice when it is injected into their eyes.
Richard Kramer at the University of California, Berkeley, and his colleagues studied a mouse model of retinitis pigmentosa — a form of blindness in which light-sensing rod and cone cells in the retina degenerate. The researchers applied the molecule, AAQ, to retinas isolated from the mice and found that it triggered retinal ganglion cells — most of which are normally light-insensitive — to increase their firing rate in response to light. Other work has suggested that the molecule functions by blocking potassium ion channels in the membranes of neurons, boosting their excitability. In behavioural tests, blind mice treated with AAQ showed signs of light sensitivity.
The use of this and related molecules could restore vision less invasively than other proposed methods, the researchers say.
Neuron 75, 271–282 (2012) http://dx.doi.org/10.1016/j.neuron.2012.05.022