Retinal Ganglion Cell Patch Recordings

Adult mice (postnatal day 42–90) C57BL/6J wild-type (WT), both sex, n = 41; Kcng4-YFP (6–8 weeks, n = 11) mice [31 (link)], which labeled α-RGC (Supplementary Figure S1) were used in the study. The animals were maintained in a 12 h–12 h day–night cycle, and all experiments were performed during daylight hours. The mice were anaesthetized deeply with an intraperitoneal injection of ketamine (Vedno, St. Joseph, MO, USA) and xylazine (Akorn, Decatur, IL, USA) [80 and 10 mg (kg body weight)⁻¹, respectively], and lidocaine hydrochloride (20 mg mL⁻¹, Sigma-Aldrich, St. Louis, MO, USA) was applied locally to the eyelids and surrounding tissue. Eyes were removed under dim red illumination and hemisected anterior to the ora serrata. Anterior optics and the vitreous humor were removed, and the resultant retina–eyecup with sclera attached, either whole or in sections, was placed in a super-fusion chamber. For patch recordings, retinas were dissected into four equal quadrants and attached to a modified translucent Millicell filter ring (Millipore, Bedford, MA, USA). The flattened retina were superfused with oxygenated mammalian Ringer solution, pH 7.4, at 32 °C [32 (link)]. The anaesthetized animals were killed by cervical dislocation immediately after the enucleations.