Figure 1.

The schedule of social defeat stress, drug administration, and behavioral tests. Repeated social defeat stress was performed for 10 days (day 1 to day 10). Social interaction test was performed day 11, and susceptible mice were used in the subsequent experiments. Vehicle, (+)-MK-801 (0.1mg/kg), or (-)-MK-801 (0.1mg/kg) was administered i.p. (day 12). Locomotion test (LMT) and tail suspension test (TST) were performed 4 and 6 hours after a single injection, respectively (day 12). Forced swimming test (FST) was performed 1 day after injection (day 13). A 1% sucrose preference test (SPT) was performed 2 days (day 14), 4 days (day 15), and 7 days (day 19) after a single injection.