*2.4.1.1 The elevated plus maze*

The elevated plus maze apparatus designed according to the description of Lister [14], and the test protocol adapted by Okon et al. [15] were used in this present study. This apparatus is used to assess the anxiety and fear levels of the mice. The test is based on the inborn aversion of rodents to open or bright illuminated spaces. The maze has two open arms (45 × 5 cm2 ) with 0.25 cm high edges and two closed arms (40 × 5 cm2 ) with 15 cm high walls radiating from a central square (5 × 5 cm). The open arms contain a slight edge (4 mm high) to prevent the mice from slipping and falling off the edge [16].

Prior to the test, the plus maze arms, surfaces and closed sides were cleaned with methylated spirit to eliminate olfactory clues and to remove faecal boll and urine. The mice were placed in the central square of the plus maze such that the mice faced an open arm away from the experimenter upon placement. Immediately after placement, a stop watch was started and the mice were allowed to explore the apparatus for 5 min. The test sessions were recorded and videotaped. Behaviours scored included open arm entry, open arm entry duration; head dip, rearing and stretch attend posture frequencies.
