Memory Enhancing Effect of Mirtazapine with Ascorbic acid on Scopolamine Induced Amnesia in Rats

Mirtazapine is an antidepressant with prominent effect on serotonergic and adrenergic transmission in brain. Ascorbic acid has been suggested as antioxidant that may protect neurons from oxidative stress. The present study is aimed to evaluate the memory enhancing effect of combination of mirtazapine and ascorbic acid in amnesic rats using several behavioral and memory tests. Amnesia was induced by scopolamine (1 mg/kg) administered i.p daily for seven days. Mirtazapine (20 mg/kg, p.o.) and ascorbic acid (40 mg/kg, p.o.) combination was given to the amnesic rats for a period of 7 days. The drugs were administered 30 min. before the test. The morris water maze apparatus, elevated plus maze apparatus and open field tests were used to evaluate the cognitive functions of the rats. Thiobarbituric acid reactive substances (TBARS), which are the indicators of lipid peroxidation and the activities of anti-oxidative enzymes were measured in the rat hippocampus and prefrontal cortex. Chronic administration of combination of mirtazapine and ascorbic acid caused significant reduction in escape latency using Morris water apparatus, transfer latency using elevated plus maze and improvement in locomotor activity indicating the improvement of cognition and locomotion. The combination of mirtazapine and ascorbic acid also caused increase in the level of antioxidant enzymes and decrease in the level of TBARS in amnesic rats indicating decrease in oxidative stress induced damage in the brain of amnesic rats. The present study concluded that combination of mirtazapine along with ascorbic acid has a distinct memory improving activity or a memory restoring effect after scopolamine treatment.