Subjects

All experiments used C57BL/6J male and female mice bred in-house or purchased from Jackson laboratories (Bar Harbor, ME). Mice were 8 to 10 weeks of age at the start of experiments. Animals were group housed 3-5 per cage in all experiments aside from the hotplate combination dosing experiments. Animals were maintained in a temperature-controlled facility with a 12-hour light-dark cycle (lights on at 06:00-18:00 hours) and given ad libitum food and water. All experimental procedures were approved by the Washington University Institutional Animal Care and Use Committee and followed the guidelines of the International Association for the Study of Pain. Mice were randomly assigned to experimental conditions. Male and female cohorts were always tested separately. Behavioral testing occurred between 8 AM and 6 PM (2:00 and 12:00 ZT).