Investigation of the molecular mechanisms involved in the optogenetic activation of neurons

Author: Yovan de Coene Co-authors: Stijn Van Cleuvenbergen, Karin Thevissen, Chris Van den Haute, Thierry Verbiest, Veerle Baekelandt, Carmen Bartic, Koen Clays Understanding the pathophysiology of many complex neural disorders requires the ability to selectively interfere and record neural activity underlying brain processes. ‘Optogenetics’ describes a variety of techniques for specifically controlling neural activity with light, using light sensitive membrane proteins (opsins) (Fiala et al. 2010). Given the significant advantages of non-linear optics, activating opsins by two-photon absorbance is already an emerging field (Oron et al. 2012). Activity read-out of by means membrane potential still relies on voltage sensitive fluorescent probes or electrode recording. However, it has been proven that retinal analogues can serve as voltage sensing probes by means of second harmonic generation (SHG) when inserted into the cell membrane (Theer et al. 2011). Since opsins use this retinal chromophore as their photoswitch, we are investigating to the potential of opsins themselves as voltage reporters. In this contribution we report the molecular first hyperpolarization of a chimeric channelrhodopsin C1C2, a parameter indicative for its potential to act as a SHG probe and compare it to that of bacteriorhodopsin from Halobacterium salinarium, a protein who's nonlinear optical properties have been widely investigated.status: submitte