Electrophysiological and Imaging Protocol for Dark-Adapted Mice

Pupils of dark-adapted mice were dilated with Cyclogyl 1% (Alcon Pharmaceuticals, Fribourg, Switzerland) and Neosynephrine 5% (Ursapharm Schweiz GmbH, Roggwil, Switzerland). Mice were anesthetized by a subcutaneous injection of ketamine (85 mg/kg, Parke-Davis, Berlin, Germany) and xylazine (4 mg/kg, Bayer AG, Leverkusen, Germany). A drop of atropin 0.5% (Thea Pharma, Schaffhausen, Switzerland) was applied to each cornea just prior to placing gold ring electrodes onto each cornea. Recordings were done with an LKC UTAS Bigshot unit (LKC Technologies, Inc. Gaithersburg, MD, USA) using flash intensities from −50 db (0.000025 cd*s/m²) to 15 db (79 cd*s/m²) for scotopic and from −10 db (25 cd*s/m²) to 25 db (790 cd*s/m²) for photopic responses. Before photopic responses were recorded, mice were light-adapted for 5 min. Ten recordings were averaged per light intensity.
For fundus imaging and OCT scans, pupils were dilated and mice anesthetized as described above. A drop of 2% methocel (OmniVision AG, Neuhausen, Switzerland) was applied to keep eyes moist. Fundus images and OCT scans were acquired using the Micron IV system (Phoenix Research Labs, Pleasanton, CA, USA) as described [51 (link)].