ABSTRACT
Substance abuse especially amongst young adults constitutes a global problem. Cannabis sativa is a commonly abused illicit drug. Some of its effects include impaired short memory, attention and reduced motor skills. Ethanol is a multiple action depressor of the central nervous system and under its influence, confused and disorganized thinking results. Both drugs have a detrimental effect on prospective memory in adults but users may not be aware of this. This study was therefore aimed at evaluating the co-administration of ethyl acetate fraction of Cannabis sativa leaves and ethanol on Learning, Memory and the histomorphology of the Hippocampus in Mice (Mus Musculus) using the Y-maze and Novel Object Recognition (NOR) paradigms. Fourty eight apparently healthy male albino mice of 20-28 g body weight were assigned into two major groups consisting of four sub-groups each; A, B, C, and D. Each sub group had six mice each (n=6). Sub-groups A, B, C, and D were administered distilled water 1 ml/kg body weight (bwt) (control), 145 mg/kg bwt ethyl acetate fraction of Cannabis sativa leaves, ethanol 20% v/kg bwt and co-administration of 145 mg/kg bwt ethyl acetate fraction of Cannabis sativa leaves and 20% v/kg bwt of alcohol respectively, orally for 21 days. Neurobehavioural assessment was carried out using the Y-maze and Novel Object Recognition (NOR) Paradigms. The Hippocampal histology and volumes were obtained using H & E staining technique and Cavalieri estimator respectively. Data were expressed as mean�SEM. One way ANOVA and Kruskal Wallis tests were used to compare the means at p<0.05. The result of Y-maze test showed a significant increase (P<0.05) in the mean rank of the co-administered group followed by the cannabis group indicating memory impairment when compared to control. NORT result showed a significant decrease (P<0.05) in discrimination and retention indexes in the co-administered group followed by the Cannabis sativa treated group when compared to control. A non-statistical significant (P>0.05) decrease was observed in Hippocampal volume when compared to the control. Histopathological evaluation revealed disorganization and focal necrosis of pyramidal cells of the hippocampus in the co-administered group when compared to the control. It can therefore be inferred from the findings of this study that, co-administration of ethyl acetate fraction of Cannabis sativa leaves with ethanol is more detrimental to hippocampal histoarchitecture with a corresponding memory impairment relative to administration of either.