A total of six male New Zealand White rabbits (16 weeks old; weight, 2.84–3.44 kg; median, 3.16 kg) housed in the same environment were evaluated. All animal experiments were approved by the Toho University Laboratory Animal Research committee (19-53-358) and performed in accordance with the Guiding Principles for the Care and Use of Laboratory Animals approved by The Japanese Pharmacological Society and the tenets of the Association for Research in Vision and Ophthalmology.
The experiments were performed with the rabbits under general anesthesia, with induction of anesthesia by ketamine (Ketalar, 35 mg/kg, intramuscular [i.m.]; Daiichi Sankyo Propharma, Tokyo, Japan) and xylazine (Selactar 2%, 5 mg/kg, i.m.; Bayer Japan, Osaka, Japan) and maintenance with isoflurane (end-tidal concentration of 1.5%; Pfizer Japan, Tokyo, Japan). After intubation of the tracheal cannula, the rabbit was mechanically ventilated (FiO2 = 1.0; tidal volume = 6 mL/kg, 40 strokes/min; SN-480-5, Shinano, Tokyo, Japan), and its body temperature was maintained at 37°C using a heating pad. The right ear vein was used for the administration of adrenaline, and the left ear vein was used for continuous maintenance infusions of saline (15 mL/h) and rocuronium bromide (0.6 mg/kg/h; Fuji Pharma, Toyama, Japan).