Figure 3. Transduction of NRVM monolayers with lentiviruses bearing ChR2 or eNpHR3.0 did not appreciably perturb action-potential morphology from control (absent optogenetic stimulation with blue or green light).

(a, d) Control NRVMs without viral transduction. (a) Transmission (top) and fluorescence (bottom) confocal images. (d) Action potentials were averaged from multiple channels of optical mapping data, with PGH1 as dye. Parallel culture to those transduced with lentiviruses in later panels. (b, e) Results for NRVM transduced with lentivirus bearing ChR2; format as in (a). (b) Fluorescence is from YFP fused to ChR2, and reflects expected membrane targeting of ChR2. (e) Action potential (blue) essentially unchanged from control (gray). (c, f) Results for NRVM transduced with lentivirus bearing eNpHR3.0; format as in (a). (c) Fluorescence is from YFP fused to eNpHR3.0, and reflects membrane targeting of optogenetic construct. (f) Action potential (green) essentially unchanged from control (gray), as copied from panel (a).