Optical modulation of ion channels using Qube Opto
Optical modulation of ion channels is traditionally studied using a manual patch clamp system combined with a light source. This approach, however, is limited by very low throughput. In the present work, we show data recorded using a 384-well based automated patch clamp system equipped with 384 integrated light sources (Qube Opto 384).
In this study, we evaluated Channelrhodopsin 2 (ChR2), a light-sensitive non-selective cation channel permeable to Na+, K+ and Ca2+ opened upon illumination (Berndt et. al., 2012). Furthermore, we employed the chloride-conducting channelrhodopsin (iC++, Govorunova et Al. 2015), which was developed from a non-selective cation conducting channelrhodopsin through a mutational approach. Finally, we used photoactivatable adenylyl cyclase, bPAC, to modulate cellular cAMP levels and thereby alter biophysical properties of the HCN2 channel (Stierl et Al., 2011).
Compound activation by light enables the pharmacological manipulation of receptors, ion channels and other proteins with a high degree of temporal control. We used caged GABA (Rubi-GABA, Zayat et. al., 2003) to study the light activation of ligands, in combination with the microfluidic flow channel of the QChip 384, to give a higher degree of experimental control.