**2.2. Experimental protocol**

A total of the forty seven male adult rats were used and were randomly divided into two groups as control (sham –pinealectomy) and pinealectomy in this study. In the control group, animals were exposed to the same surgical procedure with the experimental group except for the removal of the pineal gland. We performed the four subgroups as Melatonin (1 and 100 μg/kg) (n:14), Saline (0.9%NaCl) (n:5) and Diazepam (2mg/kg) (n:5) under control and pinealectomy groups. All pinealectomies and cannulation surgeries were applied before starting the experiment. The experiments were started after a week of the pinealectomies and implantations, when surgery wounds healed up completely. The anxiety-like behaviour of animals were tested by open field and elevated plus maze tests, and spatial memory was tested by means of the Morris water maze test. All animals were exposed to these behavioral tests after 30 minutes of melatonin, saline, and diazepam administrations.
