2.6. Open Field Test (OFT)

The spontaneous locomotor activity was evaluated by following previously described methods [12, 17, 20]. The apparatus consisted of a square box (75 cm × 75 cm with 42 cm height) made up of plexiglass material. Top of the box was not covered and was kept open to see the movement of animal. The floor and all sides of the box were covered with white cardboard material. The cardboard at the floor of the box was drawn with black lines dividing the floor into equal squares of 15 cm × 15 cm.

On postpartum day 15, the animals were transferred to OFT test room and acclimatized for 1 hr. The animals were placed onto the center of the box and allowed to explore the box freely for 5 min. After conducting the test on each animal, the box was cleaned with dry tissue paper first and later with 70% alcohol solution and was allowed to dry in air to avoid the influence of urine and feces of the previous animal on the next animal. The top view of the box was recorded by a video camera mounted on the ceiling. The video recordings were later scored by an observer blind to the treatment regimen for number of squares crossed and number of rearings. After the OFT, the same animals were tested in FST on the postpartum day 15.