Locomotor Activity

Motor activity in mice was assessed in a 21 × 21 × 30 cm³ open field (Omnitech Inc., Columbus, OH) as described.⁶³ The mice were housed in the test room 24 h prior to testing. Animals were injected (i.p.) with the vehicle or different doses of ML321 and immediately placed into the open field. After 30 min, the mice were removed and injected with the vehicle, 3 mg/kg AMPH, or 6 mg/kg PCP and returned immediately to the open field for an additional 90 min. Horizontal distance traveled (cm) was quantitated with Fusion software (Omnitech) and scored in 5 min bins across testing or as cumulative locomotor activity at baseline (0–30 min) or post-injection (31–120 min).