Suvorexant Oral Administration Protocol

Suvorexant (Belsomra^®; Merck, Whitehouse Station, NJ, United States of America) pills (20 mg) were crushed and dissolved in a 20% vitamin E TPGS (D-α-tocopherol polyethylene glycol 1,000 succinate; Mazuri, Richmond, IN, United States of America) solution (Cox et al., 2010 (link); Guo et al., 2013 (link); Ehlers et al., 2020 (link)) which was also used for control (i.e., 0 mg/kg SUV) group injections. Once homogenized, to maximize bioavailability of the compound, SUV was administered 30 min before the test sessions at doses of 0, 10, and 20 mg/kg (5 mL/kg, p. o.; based on previously reported doses: Simmons et al., 2017 (link); Gentile et al., 2018 (link)). Oxycodone hydrochloride (Spectrum Chemicals, St. Louis, MO, United States of America) dissolved in 0.9% sodium chloride (Hospira, United States of America) was administered intravenously (i.v., 0.15 mg/kg/0.1 mL; Wade et al., 2014 (link); Matzeu and Martin-Fardon, 2020 (link)).