2.9 Open field test
Spontaneous locomotor activity of experimental C57BL/6J mice was studied in the open field paradigm over a 5-min period(Zhi, Jin, Pan, Zhang, & Liu, 2019), and separate groups of animals were used for this test. The open field was divided into two areas, a peripheral area and a square center. C57BL/6J mice were individually placed in the central of a wooden box (height 40 cm, width 100 cm, length 100 cm). The test room was illuminated with a red bulb (50 W) on the ceiling dimly. For open field observations, the animals were placed in the central sector 30 minutes after a single injection. The computer software (EthoVision; Noldus) calculated the velocity of movement, the distance of traveling, and the time spent in the center of the open field. For each group, the mean value and SEM was calculated. These parameters are thought to reflect locomotor activity and fear or anxiety, respectively. The open field apparatus was thoroughly cleaned between each trial.