Nootropic action of Glycyrrhiza glabra root extract on the dendritic morphology of hippocampal ca1 neurons in adult rats

Abstract

Our earlier studies have shown that Glycyrrhiza glabra (family: Leguminosae) aqueous root extract treatment in Wistar albino rats enhances both spatial learning ability and retention of learned tasks accordingly, the present study was designed to investigated the nootropic action of aqueous root extract of Glycyrrhiza glabra treatment on the dendritic morphology (dendritic arborization and dendritic intersections) of hippocampal CA1 neurons in one month old male Wistar albino rats. Methods: The aqueous root extract of Glycyrrhiza glabra was administered orally in four doses (75, 150, 225 and 300 mg/kg) for 6 weeks. After the treatment period, all experimental animals were subjected to spatial learning (Morris water maze, Hebb-William’s maze and elevated plus maze) tests. At the end of the spatial memory tests, the rats were deeply anesthetized with Pentobarbitone and killed their brains were removed rapidly and fixed in rapid Golgi fixative. Hippocampal CA1 neurons were traced using Camera lucida , and dendritic arborization and intersections were quantified. These data were compared with those of age-matched control rats. Results: Results showed that all the doses of aqueous root extract of Gg significantly enhanced dendritic arborization (dendritic branching points) and dendritic intersections however in the dose of 150 and 225 mg/kg/p.o showed a significant (p<0.01) enhancement of dendritic arborization and dendritic intersections along the length of both apical and basal dendrites in hippocampal CA1 pyramidal neurons is comparable to control. Conclusion: Based on our results obtained, we conclude that constituents present in aqueous root extract of Glycyrrhiza glabra have neuronal dendritic growth stimulating properties.