Adult male C57BL/6 mice (Jackson Laboratories, Bar Harbor, Maine; 2–5 months old) were group-housed in the animal facility at the University of Connecticut Health Center on a 12 h light/dark cycle (lights, 7:00am–7:00pm) and handled in accordance with Institutional Animal Care and Use Committee guidelines. After acclimation for one week, animals were handled for 1 min/day for 2–3 days prior to injections. On each treatment day, animals were allowed to acclimate to the behavior room for 45–60 minutes before beginning injections.
