Direct-Coupled Electroretinogram Recording of the Retinal Pigment Epithelium in a Mouse

Begin with a dark-adapted, anesthetized mouse.

Apply anesthetic and dilating drops to the cornea.

Place the mouse on a raised platform in front of a dome with a dim red light. 

Secure a ground electrode subcutaneously on the hind leg and a reference electrode inside the mouth.

Take an electrode holder with a capillary filled with salt solution. Flick to remove air bubbles.

Fill the capillary tip fully with the salt solution.

Position the capillary on the cornea to record a direct-coupled electroretinogram or DC-ERG.

The DC-ERG measures subtle electrical responses of the retinal pigment epithelium or RPE.

RPE is a specialized cell monolayer that maintains the health and structural integrity of photoreceptor cells.

Apply a drop of eye lubricant to maintain conductivity and prevent desiccation.

Check the resistance values for each eye to ensure they are similar and within range.

Establish a stable baseline, and then start recording the DC-ERG.

To position the mouse and electrodes for an experiment, anesthetize the cornea of a sedated mouse with a drop of 0.5% Proparacaine Hydrochloric acid before dilating the cornea with a drop of 2.5% Phenylephrine HCl and 0.5% tropicamide.

Use step