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 2014-03, Vol.4 (3), p.213-218
• Main Authors: Oyewole, Aboyeji Lukuman, Owoyele, Bamidele Victor
• Format: Article
• Language: English
• Subjects: Basic Researches; Carica; Carica papaya; Hippocampus; Maze; memory; papaya; Rats; Smoking; Spatial; Spatial memory
• ISSN: 2221-1691; 2588-9222
• DOI: 10.1016/S2221-1691(14)60234-3

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 1served 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.Result: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 appcarance 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.