(c) flickr & f_shields
目に注入することで，盲目のマウスの視力を一時的に回復させる化合物が発見された。実験に使われたのは，光に反応する網膜細胞，杆体・錐体が数カ月で死滅するよう遺伝子操作したマウスだ。この化合物AAQは，杆体・錐体が光に反応するのと同様に光に反応し，網膜の神経細胞を活性化する。現在，効果がより長く，何日も続く類似の化合物が研究されており，遺伝による失明の原因として最も一般的な網膜色素変性症や，後天的な失明原因の第一位である加齢性黄斑変性の患者に効果が期待される。局所麻酔薬が切れるように，投与された化合物は徐々に消失するため，幹細胞や遺伝子を使う治療より安全と考えられる。（吉田素子）
Chemical Makes Blind Mice See
A team of University of California, Berkeley, scientists in collaboration with researchers at the University of Munich and University of Washington, in Seattle, has discovered a chemical that temporarily restores some vision to blind mice, and is working on an improved compound that may someday allow people with degenerative blindness to see again.
The approach could eventually help those with retinitis pigmentosa, a genetic disease that is the most common inherited form of blindness, as well as age-related macular degeneration, the most common cause of acquired blindness in the developed world. In both diseases, the light sensitive cells in the retina -- the rods and cones -- die, leaving the eye without functional photoreceptors.
The chemical, called AAQ, acts by making the remaining, normally “blind” cells in the retina sensitive to light, said lead researcher Richard Kramer, UC Berkeley professor of molecular and cell biology. AAQ is a photoswitch that binds to protein ion channels on the surface of retinal cells. When switched on by light, AAQ alters the flow of ions through the channels and activates these neurons much the way rods and cones are activated by light.
“This is similar to the way local anesthetics work: they embed themselves in ion channels and stick around for a long time, so that you stay numb for a long time,” Kramer said. “Our molecule is different in that it’s light sensitive, so you can turn it on and off and turn on or off neural activity.”
［単語和訳］
Mice：マウス
in collaboration with：～と共同して researchers：研究者 temporarily：一時的に vision：視力 is working on：～の開発に取り組んでいる compound：化合物 degenerative：退行性の，変性の blindness：盲目
retinitis pigmentosa：網膜色素変性症 genetic disease：遺伝性疾患 inherited：遺伝による age-related macular degeneration：加齢性黄斑変性症 acquired blindness：後天盲 developed world：先進国 light sensitive：光に敏感な cells：細胞 retina：網膜 rods：杆体 cones：錐体 functional：機能的な photoreceptors：光受容体
molecular and cell biology：分子細胞生物学 photoswitch：光スイッチ protein ion channels：タンパク質イオンチャンネル retinal cells：網膜細胞 activates：～を活性化する neurons：神経細胞
local anesthetics：局所麻酔薬 embed：～を組み込む stick around：そこにいる numb：感覚を失った in that：～という点で neural activity：神経活動
