Electrophysiological Recording of Voltage Responses of Drosophila Retinal Photoreceptors to Light Stimuli

Mount a Drosophila fly on a holder with its head exposed.

Create an opening in one eye and remove the cornea to expose the retina.

Place the holder on the recording platform.

Insert a blunt reference electrode containing a physiological saline solution into the head capsule.

Next, insert a sharp recording electrode containing an intracellular environment-mimicking solution through the opening into the retina.

Allow the eye to dark-adapt.

Measure the recording electrode's resistance to ensure its suitability for recording.

Then, eliminate the baseline voltage difference between the recording and reference electrodes.

During dark adaptation, specific ion channels in the retinal photoreceptor cells remain open, allowing a steady positive ion influx.

Stimulate the eye with light flashes.

In response, the ion channels close, reducing positive ion influx and promoting efflux.

Consequently, the membrane potential of the photoreceptors becomes more negative, measured by the recording electrode as a dip in the voltage.