Impact of Ketamine on Spontaneous Coordinate Activity and Short Memory Behavior in Rodents´ Chronic Unpredictable Stress Model

Introduction/Objective. This research aims to evaluate the impact of chronic stress on behavioral effects of ketamine, which are still not sufficiently clear. Methods. Wistar male rats aged five weeks were used in the experiment. The animals were divided into two equal groups: control and experimental. After being exposed to a chronic unpredictable stress paradigm for 42 days, experimental rats received a single injection of ketamine (10 mg/kg; day 45) as did the control group. The impact of ketamine was assessed using behavioral tests, spontaneous coordinate activity, and water maze tests for the evaluation of short-term memory. Results. The experimental group rats showed less spontaneous motoric activity than before ketamine application. Statistical significance was shown in gaining weight after time of ketamine application in the control group, as well as in the experimental group, where they showed weight loss during stress paradigm and then increased their weight after ketamine application. There was no statistical significance in speed measurements in either group, showing no effects on short-term memory behavior. Conclusion. These findings show that ketamine in a single subanesthetic dose has antidepressant and anxiolytic-like effects in male rats exposed to chronic unpredictable stress paradigm.