Forced swimming test

The forced swimming test (FST) was conducted according to the method described by previously report [41]. The rats were placed individually to swim in a plastic cylinder (height: 40 cm, diameter: 20 cm) filled with 15 cm of 25 ± 1°C water. The total duration of the stress exposure and behavior were recorded in digital video during the FST. The experiment consisted of two sessions. In a pretest session, each animal was forced to swim individually for 15 min in the water-filled plastic cylinder as an adaptive drill. Twenty-four hours after, the animals were again subjected to 5-min test session of FST. Videos were analyzed by individuals blind to the experimental conditions, and the immobility behavior and escape responses (such as climbing and swimming) was quantified during the test period.