Long–term spatial memory and morphological changes in hippocampus of Wistar rats exposed to smoke from Carica papaya leaves

• Published in: Asian Pacific Journal of Tropical Biomedicine
• Main Authors: Aboyeji Lukuman Oyewole, Bamidele Victor Owoyele
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wolters Kluwer Medknow Publications 2014
• Subjects: Maze; Spatial memory; Smoking; Carica papaya; Rats; Hippocampus; Arctic medicine. Tropical medicine; RC955-962; Biology (General); QH301-705.5; Arctic
• Online Access: https://doi.org/10.1016/S2221-1691(14)60234-3; https://doaj.org/article/b4dac64858cd49c4aeddc560f1a4eff2

Objective: To investigate the effects of smoking of dried leaves of Carica papaya (pawpaw) based on ethnopharmacological information which indicated that smoking of papaya leaves could influence motor performance and learning. Methods: Twenty-four rats were used for the study, and were grouped into four groups. Groups 1 served as the control (not exposed to papaya leaves smoke), while Groups 2, 3 and 4 were exposed to smoke from 6.25 g, 12.50 g and 18.75 g of dry pawpaw leaves respectively in a smoking chamber twice daily for 21 d with each exposure lasting for 3 min. Lastly, hippocampus was harvested in each group for histological study. Results: The results showed that there were significant (P<0.05) increases in mean of recall latencies of long-term spatial memory in the animal administered the high dose while the other groups had significantly (P<0.05) lower frequencies. Histological investigation showed signs of mild neural degeneration in high dose group and hypochromic appearance of the Nissl substance in all treated groups. Conclusions: In conclusion, the findings from this study has demonstrated that smoking of papaya leaves has the ability to maintain an intact long-term spatial memory at all doses but retrieving such memory is faster with the low and medium dosages.