S130c photodiode sensor

Whole-cell patch-clamp recordings on DRG neurons were conducted at room temperature, 24 h after plating. The internal solution (pH 7.2) of the pipette contained the following (in mm): 130 K-gluconate, 1 MgCl₂, 10 HEPES, 5 EGTA, 3 MgATP, and 0.4 GTP. The bath solution, pH 7.4, contained the following (in mm): 152 NaCl, 5 KCl, 2 CaCl₂, 1 MgCl₂, 10 HEPES, and 10 glucose. Patch pipettes had a tip resistance of 5–10 MΩ. Electrophysiological recordings were conducted using an Axopatch 200B amplifier, digitized with a Digidata 1322A interface (Axon Instruments). Traces were acquired and analyzed using pClamp 8.2 software (Axon Instruments). Recordings were low-pass filtered at 2 and 5 KHz in voltage- and current-clamp configurations, respectively. Multimode optic fibers (200 μm diameter; Thorlabs), coupled to diode-pumped solid-state lasers of specific wavelengths (473 nm blue laser, Laserglow Technologies; or 589 nm yellow laser, Dragon Lasers), were used for optical stimulation of DRG neurons. Stimulation parameters are specified in each condition. Light intensities were measured using a PM100A power meter coupled to a S130C photodiode sensor (Thorlabs) and analyzed using LabVIEW 8.5 software.