FIG. 1.
Channelrhodopsin mutant H134R has enhanced responsiveness to blue light. A: schematic of larval motor neuron whole cell patch preparation. Left: filleted larva showing brain (Br) ventral ganglion (VG) and body wall muscles. Right: close up view of ventral ganglion, dorsal motor neuron designations, and recording configuration. B: whole cell patch recordings from MN30-Ib cells expressing ChR2 and H134R-ChR2. One-second blue light pulses (gray bars, 450 μW/mm2, 470 nm) evoked spiking in both cells. C: cells expressing ChR2-H134R showed significantly higher firing rates through a range of blue light intensities than cells expressing ChR2. D: response to DC current injection was similar in both genotypes. Holding potential for all experiments was −50 mV. Resting membrane potential and input resistances were not significantly different between genotypes. Pooled data are presented as means ± SE. P values (Student's t-test) for each intensity (50, 12, 245, 450, 760 μW/mm2) were 0.15, 0.07, 0.03, 0.03, and 0.03, respectively.