RESUMO
BACKGROUND: In Ayurveda; an Indian system of traditional medicine, Ocimum sanctum is said to have remedial effect on hriddaurbalya (problems affecting the mind), aakshepayukta vikara (nervous disorders) and shiroroga (diseases of head). Hence, in Ayurvedic practice, it is profoundly used as an antistress medicine. Stress is known to affect neurons of functionally significant brain regions like substantia nigra. However, experimental evidence showing its effect on morphology of substantia nigral neurons is lacking. In addition, whether the O. sanctum treatment attenuates stress induced substantia nigral neuronal structural changes is not known. OBJECTIVES: To know the effect of stress on morphology of substantia nigral neurons and the effect of O. sanctum fresh leaf extract (OSE) on substantia nigral neurons of stressed rats. MATERIAL AND METHODS: Present study included three experiments. Experiment I: To study the effect of 3 and 6 weeks of foot shock stress in rats; Experiment II- To study the effect of 3 weeks of OSE treatment on 3 week-stress undergoing rats and on 3 week-stressed rats; Experiment III- To study the effect of 6 weeks of OSE treatment in 6 week-stress undergoing rats and in 6 week-stressed rats. RESULTS: In experiment I, stress had significant deleterious effect on dendritic arborization of substantia nigral neurons. Experiments II and III showed prevention and attenuation of the stress induced dendritic atrophy of substantia nigral neurons in both 2 ml and 4 ml OSE treatment groups. Protective effect of OSE was more pronounced in rats which are treated for a longer duration. CONCLUSIONS: Foot shock stress induces neuronal damage in the substantia nigra of rats. Treatment with fresh leaf extract of O. sanctum could prevent and attenuate the foot shock stress induced behavioral deficit and substantia nigral neuronal damage.
RESUMO
OBJECTIVE: Centella asiatica (CeA), a creeper, growing in moist places in India and other Asian countries. Leaves of CeA are used for memory enhancement in Ayurvedic system of medicine, an alternative system of medicine originated from India. In the present study, we have investigated the role of CeA fresh leaf extract treatment on adult rats on dendritic morphology of amygdaloid neurons, one of the regions concerned with learning and memory. METHODS: Adult rats (2.5-month old) were fed with 2, 4 and 6 mL/(day kg) of fresh leaf extract of CeA for 2, 4 and 6 weeks. After the treatment period the rats were killed, brains were removed and amygdaloid neurons were impregnated with silver nitrate (Golgi staining). Such silver impregnated amygdaloid neurons were traced using camera lucida and dendritic branching points (a measure of dendritic arborization) and intersections (a measure of dendritic length) were quantified. These data were compared with those of age matched control rats. RESULTS: The results showed a significant increase in the dendritic length (intersections) and dendritic branching points in amygdaloid neurons of the rats treated with higher dose [6 mL/(day·kg)] of CeA for longer period of time (i.e. 6 weeks). CONCLUSIONS: Constituents/active principles present CeA fresh leaf extract has neuronal dendritic growth stimulating property; hence it can be used for enhancing neuronal dendrites in stress and other neurodegenerative and memory disorders.
RESUMO
OBJECTIVE: To investigate the role of Centella asiatica (CeA) fresh leaf extract treatment on the behavior, especially learning and memory, of adult rats. METHODS: Adult rats (2.5 months old) were fed with 2, 4, and 6 ml/kg body of fresh leaf extract of CeA for 2, 4, and 6 weeks. After the treatment period the rats were subjected to spatial learning (T-Maze) and passive avoidance tests along with age matched normal and saline control rats. The data were compared with those of age matched control rats. The study was conducted at the Melaka Manipal Medical College, Manipal Academy of Higher Education, Manipal, Karnataka, India between December 2001 and February 2005. RESULTS: The rats treated with a higher dose (6 ml) of CeA showed improvement in spatial learning performance, namely, increased (p<0.001) number of alternations and decreased (p<0.001) percentage bias during spontaneous alternation test and increased (p<0.001) percentage bias during rewarded alternation test. They also showed enhanced memory retention power, namely, less (p<0.001) time spent in the small compartment during the retention period of passive avoidance test. CONCLUSION: This indicates that treatment with higher doses of CeA fresh leaf extract enhances learning ability and memory retention power in adult rats.