Department of Physiology and Biophysics, University of California-Irvine, Irvine, CA 92697, USA.
Science. 2011 Mar 18;331(6023):1409-13. doi: 10.1126/science.1199702. Epub 2011 Mar 3.
Light-responsive neural activity in central brain neurons is generally conveyed through opsin-based signaling from external photoreceptors. Large lateral ventral arousal neurons (lLNvs) in Drosophila melanogaster increase action potential firing within seconds in response to light in the absence of all opsin-based photoreceptors. Light-evoked changes in membrane resting potential occur in about 100 milliseconds. The light response is selective for blue wavelengths corresponding to the spectral sensitivity of CRYPTOCHROME (CRY). cry-null lines are light-unresponsive, but restored CRY expression in the lLNv rescues responsiveness. Furthermore, expression of CRY in neurons that are normally unresponsive to light confers responsiveness. The CRY-mediated light response requires a flavin redox-based mechanism and depends on potassium channel conductance, but is independent of the classical circadian CRY-TIMELESS interaction.
光响应性中枢脑神经元的神经活动通常通过外部光感受器的视蛋白信号传递。黑腹果蝇中的大型侧腹兴奋神经元（lLNv）在没有任何视蛋白感受器的情况下，对光的反应在几秒钟内增加动作电位的发放。膜静息电位的光诱导变化发生在大约 100 毫秒内。光反应是对与隐色素（CRY）的光谱灵敏度相对应的蓝波长的选择性。cry 缺失系对光无反应，但在 lLNv 中恢复 CRY 表达可恢复其反应性。此外，在通常对光无反应的神经元中表达 CRY 可赋予其反应性。CRY 介导的光反应需要黄素氧化还原机制，并依赖于钾通道电导，但独立于经典的昼夜节律 CRY-TIMELESS 相互作用。
