Lam et al., 2017 - A high-conductance chemo-optogenetic system based on the vertebrate channel Trpa1b. Scientific Reports   7:11839 Full text @ Sci. Rep.

Fig. 1 ZFIN is incorporating published figure images and captions as part of an ongoing project. Figures from some publications have not yet been curated, or are not available for display because of copyright restrictions.

Fig. 2

Exogenous expression of zTrpa1b in sensory neuron of trpa1b−/− mutants and sub-cellular photo-activation. (a) Maximum intensity projection showing mosaic expression of zTrpa1b in Rohon-Beard neurons in the trunk of a zebrafish larva at 2.5 dpf. Red arrows and arrowheads indicate the Rohon-Beard neuronal cell body and its neurite projection, respectively. (b) Photomotor response was tested in trpa1b mutant (trpa1b−/−) controls, or in trpa1b mutants expressing zebrafish Trpa1b (zTrpa1b), zebrafish Trpa1a (zTrpa1a) or human TRPA1 (hTRPA1) in Rohon-Beard neurons (Video S1), pretreated with 10 µM optovin. Values are means ± SEM from more than 3 experiments. Each experiment has n > 10 per condition. *p < 0.05. (c) Subcellular photo-activation of a zTrpa1b expressing Rohon-Beard neuron in a trpa1b mutant. MIP, confocal maximum intensity projection. Representative single plane time series images with photo-activation targeting neuron cell body (n = 10) (left panel; Video S2) or neurite (n = 9) (right panel; Video S3) in the trunk region of a zebrafish larvae in vivo. Red rectangular box indicates the time and location where photo-activation was made. (d) Current-Voltage relationships of zTrpa1b currents without treatment (black), 10 μM Optovin alone (green), 10 μM Optovin and light (magenta) and AITC (blue) (e) Peak whole cell zTrpa1b currents measured at −100 mV (black trace) and +100 mV (red trace); Optovin-dependent photocurrents are highlighted in blue boxes, bounded by light switch-on (magenta bulb) and light switch-off (gray bulb). (f) Data from (e) with higher time resolution. (g) Box chart showing peak current densities of zTrpa1b in indicated conditions at −100 mV and +100 mV (n = />9, error bars represent SEM).

Fig. 5

Optogenetic pacing of zebrafish hearts in vivo and human stem cell-derived cardiomyocytes in vitro. (a) Diagram of zebrafish larval heart. Magenta circle indicates the location of photo-activation. V, ventricle; A, atrium; Ant, anterior. (b) Heart pacing experiment on trpa1b−/− larvae expressing zTrpa1b in the cardiomyocytes at 2 dpf. Heart pacing was performed by photo-activating the atrium of the heart in vivo with violet light. Representative graphs show the change in heart rate for Tg(cmlc:Trpa1b-2A-EGFP) (black line, n = 11, Video S4) or trpa1b−/− control (blue line, n = 7) and the corresponding photo-activation frequency (magenta line) with 10 μM optovin. (c) Absorbance of optovin and 4g6 at the indicated wavelengths. (d) Similar heart pacing experiment as in (e) with 10 μM 4g6 treatment (Video S5; n = 8). (e) Brightfield image of zTRPA1b-expressing human stem cell-derived cardiomyocyte with sub-region indicated for the trace in (f). (f) Mean pixel intensity over time as an index of local contractile-displacement in the presence of 4g6. Photoactivation light pulses are indicated with magenta bar. Asterisk indicates a loss of 1:1 pacing-capture at a high photo-activation frequency (n = 3).

Acknowledgments:
ZFIN wishes to thank the journal Scientific Reports for permission to reproduce figures from this article. Please note that this material may be protected by copyright. Full text @ Sci. Rep.