Anthony T Eduviere¹, Lily O Otomewo² , Onoriode A Udi³, Adefunke O Opajobi⁴, Emuesiri G Moke¹

Abstract

Purpose: To evaluate the benefit of verapamil on stress-induced memory impairment in mice. Methods: Forty-eight (48) mice were used in this study. They were divided into two equal groups based on the two models of stress used in this study (sleep deprivation and hypoxia). Each model was further divided into 4 groups of six animals each. The mice in the sleep deprivation model were suspended on a platform above water while in the hypoxic model, mice were locked in an airless container for 20 min daily throughout the experiment. As for the intervention, 25 and 50 mg/kg verapamil were pre-administered via the oral route to study groups, except the normal control group and negative control group in both models. After seven-day stress and intervention, the mice were subjected to behavioural tests (Y-maze and object recognition tests), biochemical assays (for acetylcholinesterase activity) and histochemical analysis. Results: Stress caused a significant (p < 0.05) impairment in the consolidation and retrieval of working and recognition memories. Also, acetylcholinesterase activity was significantly (p < 0.05) enhanced in the stressed groups when compared to control groups. Similarly, the histological analysis revealed a significant decline in population (p < 0.05), distribution and density of viable neurons in specific areas of the hippocampus and prefrontal cortex. These alterations were significantly (p < 0.05) attenuated in verapamil-treated groups almost in a dose-dependent pattern. Conclusion: Verapamil displays significant memory-enhancing effects in two (2) murine models of stress. Antihypertensives should therefore be considered a viable prospect in the management of stress-related memory disorders after additional studies have been done to establish the mechanisms of action.