Figure 1: EGABA can be modulated, by using voltage clamp to direct chloride movement through ChloC or GtACR.
From: Cl-out is a novel cooperative optogenetic tool for extruding chloride from neurons
(a) Example traces of gramicidin patched neurons which express GtACR, showing control responses to a puff of the GABAA agonist, muscimol (black) when the cell is held at either −50 mV (upper) or −80 mV (lower). The blue traces are repeat trials in the same cells, with a prior activation of GtACR for 4 s, stopping 200 ms before the muscimol application. Voltage ramps were applied close to the peak of the muscimol response to determine EGABA more accurately (the ramps are excised from this figure so as to illustrate better the change in the IPSC shape. An example showing the ramps is in Supplementary figure 1). (b) Pooled data showing that the holding potential influences opsin-mediated shift in EGABA, with positive shifts resulting when the cell is held at −50 mV, and negative when the cell is hyperpolarized (ChloC, n=6 neurons; GrACR2, n=5). (c) Example recording of a neuron transfected with GtACR2 only, illustrating the current clamp assay of the shift in EGABA. (d) Group data for the shift in IPSP voltage following a 5 s opsin activation, in cells transfected either with GtACR2 (n=6) or ChloC (n=8).
