Investigating Prolonged Depolarizing Afterpotential (PDA) in <em>Drosophila</em> Photoreceptors

Source: Gutorov, R., et al. Electrophysiological Methods for Measuring Photopigment Levels in Drosophila Photoreceptors. J. Vis. Exp. (2022). This video demonstrates an experimental protocol to investigate the prolonged depolarizing afterpotential (PDA) in white-eyed Drosophila. The fly's eye is exposed to intense blue light pulses to convert the photopigment rhodopsin to metarhodopsin, initiating a signaling cascade that opens positive ion channels and causes membrane depolarization. Because blue light prevents the reconversion of metarhodopsin to rhodopsin, the continuous influx of positive ions results in sustained depolarization, known as the prolonged depolarizing afterpotential (PDA).