Abstract: An ultraviolet light source is added to a high-throughput electrophysiogical measurement system to allow for rapid chemical stimulation via caged compound release to a plurality of measurement samples. The integrated electrophysiogical measurement system includes a computer-controlled data collection system, an integrated electronics head for making parallel electrical measurements, and an integrated fluidics head used in part to transfer test compounds into the measurement process. This light source, and associated light coupling to a plurality of test samples, is used in conjunction with the system to make effectuate high-throughput electrical measurements with respect to fast-acting, chemically-activated electrophysiological events. The UV-source modification allows for rapid stimulation and measurement of multiple fast ligand-gated ion channel events in parallel.