Fig. 3: Silencing efficiency of Aion and GtACR1CA in CA1 pyramidal neurons. | Communications Biology

Fig. 3: Silencing efficiency of Aion and GtACR1CA in CA1 pyramidal neurons.

From: Aion is a bistable anion-conducting channelrhodopsin that provides temporally extended and reversible neuronal silencing

Fig. 3

a Membrane voltage trace showing reversible suppression of depolarization-induced action potentials (APs) by photoswitching Aion between open and closed state with a blue (460 nm, 20 ms, 10 mW/mm2) and an orange light pulse (595 nm, 1 s, 10 mW/mm2), respectively. Right: Quantification of spike rate during current injection at indicated time intervals: before channel opening (0–5 s), after channel opening (5–40 s), and after channel closing (45–50 s) in Aion-expressing CA1 neurons (n = 10 cells). b Same as (a) but for neurons expressing GtACR1CA (n = 5 cells). The channel was opened with a green (525 nm, 20 ms, 10 mW/mm2) light pulse. Note that in GtACR1CA-expressing cells AP firing could not be recovered immediately after illumination with red light (660 nm,1 s, 10 mW/mm2). c Current ramps were injected into Aion-expressing neurons to induce APs before and after illumination with a short blue light pulse (460 nm, 1 s, irradiances from 0.001 to 10 mW/mm2). For each ramp, the injected current at the time of the first AP was defined as the rheobase. Example membrane voltage traces are shown for the trial in which a light intensity of 10 mW/mm2 was used. d Quantification of the rheobase shift and (e) the relative change in the number of current ramp-evoked APs over 47 s after light stimulation (460 nm, 1 s, 10 mW/mm2) (n = 7 cells). f Number of APs evoked during the first current ramp after opening of Aion with 1 s blue light at indicated irradiances. Significant AP block was achieved at 0.1 mW/mm2 (n = 7 cells). g–j Same experiment as shown in (c–f) except that CA1 neurons expressed GtACR1CA (n = 6 cells in h, i and 7 cells in j) and 525 nm-light was used for channel opening. Note that GtACR1CA silencing efficacy decayed already within the first minute after light stimulation (i, j). For (a, b, d–f, and h–j) filled circles represent single measurement data points and black circles correspond to medians, Friedman test, *p < 0.05, **p < 0.01, ***p < 0.001, n.s. not significant.

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