Cannabis sativa and the Expression of Glial Fibrillary Acidic Protein (GFAP) in the Rat Hippocampal Astrocytes

Aims: In rodents, the hippocampus has been studied extensively as part of a brain system responsible for spatial memory and navigation. The hippocampus is one of the first regions of the brain to suffer damage in Alzheimer's disease. The hippocampus is one of the areas of the brain richly endowed with cannabinoid-1 (CB1), receptors. Recent studies in animal models and in the clinic suggest that CB1 receptor antagonists could prove useful in the treatment of parkinsonian symptoms. Delta-9-tetrahydrocannabinol, Δ9 – THC, activates dopaminergic neurons of the midbrain ventral tegmental area. Research had also reported a correlation between Cannabis use and increased cognitive function in schizophrenic patients. Advanced grades of Huntington's disease, HD, showed an almost total loss of CB1 receptors in HD. The research article aims to investigate and compare the role of different preparation of Cannabis sativa via different routes of administration on learning, memory, and on the histology of the hippocampus in order to elucidate the best form of therapeutic use of the opiate in front of different type of diseases.

Place and Duration of Study: Department of Anatomy, Faculty of Basic Medical Sciences, University of Uyo, between 2012 and 2014.

Methodology: The rats used for the study were divided into 5 groups comprising of A, B, C, D and E. Group A, 5 in number, served as the control and were given normal saline. Group B was divided into 3 subgroups, namely B1, B2 and B3, each comprising of 5 rats, and were given 0.41 mg/kg, 0.2 mg/kg, and 0.13 mg/kg, respectively, of Soxhlet extract of Cannabis sativa via oral ingestion. Group C comprised of subgroups C1, C2 and C3, each also made up of 5 rats was given 4grams, 2grams and 1grams, respectively, of grounded dried leaves of Cannabis sativa via inhalation. Group D also has 5 rats in each subgroup namely D1, D2, D3, and were given a mixture of 8grams, 4grams and 2 grams of grounded dried leaves of Cannabis sativa and 90 grams of animal feed in each case, while rats in Group E were given 1gm of 10% Tween 80 via oral ingestion. Before and after 28 days of administration of Cannabis sativa, the Morris water maze experiments on neurobehavioral were carried out. Sections were stained using GFAP immunostaining method. Data were expressed as means ± standard error of the mean and subjected to one way analysis of variance (ANOVA) using PRIMER, EXE, version 3.01. Significant differences between means were assessed by Student-Newman-Keuls post hoc test. 95% level of significance (P =.05) was used for the statistical analysis; while Microsoft excel 2010 package was used for graphs and error bars.

Results: Cannabis sativa obtained via soxhlet extraction technique has a mild and tolerable psychoactive effect compared to other preparations of Cannabis sativa.

Conclusion: This mode of preparation can be employed in the development of therapeutic strategies in view of its very low toxicity, thus presents a better method to be adopted in preparation of medical Cannabis.