Enhancement of basolateral amygdaloid neuronal dendritic arborization following Bacopa monniera extract treatment in adult rats

OBJECTIVE: In the ancient Indian system of medicine, Ayurveda, Bacopa monniera is classified as Medhya rasayana, which includes medicinal plants that rejuvenate intellect and memory. Here, we investigated the effect of a standardized extract of Bacopa monniera on the dendritic morphology of neurons in the basolateral amygdala, a region that is concerned with learning and memory. METHODS: The present study was conducted on 2¹/2-month-old Wistar rats. The rats were divided into 2-, 4- and 6-week treatment groups. Rats in each of these groups were further divided into 20 mg/kg, 40 mg/kg and 80 mg/kg dose groups (n = 8 for each dose). After the treatment period, treated rats and age-matched control rats were subjected to spatial learning (T-maze) and passive avoidance tests. Subsequently, these rats were killed by decapitation, the brains were removed, and the amygdaloid neurons were impregnated with silver nitrate (Golgi staining). Basolateral amygdaloid neurons were traced using camera lucida, and dendritic branching points (a measure of dendritic arborization) and dendritic intersections (a measure of dendritic length) were quantified. These data were compared with the data from the age-matched control rats. RESULTS: The results showed an improvement in spatial learning performance and enhanced memory retention in rats treated with Bacopa monniera extract. Furthermore, a significant increase in dendritic length and the number of dendritic branching points was observed along the length of the dendrites of the basolateral amygdaloid neurons of rats treated with 40 mg/kg and 80 mg/kg of Bacopa monniera (BM) for longer periods of time (i.e., 4 and 6 weeks). CONCLUSION: We conclude that constituents present in Bacopa monniera extract have neuronal dendritic growth-stimulating properties.

Integrated practical examination: a novel approach to evaluate undergraduate medical students in physiology practices.

Background: The development of a reliable and valid method to assess laboratory exercises in preclinical sciences is a challenging task. The use of different assessment methods helps assess various aspects of clinical competence. Integrated Practical Examination (IPE) was thus incorporated as an assessment tool in physiology at Melaka Manipal Medical College (Manipal Campus), India aiming to test a wide range of practical skills and to improve the validity of our practical examinations. Methods: Three batches of first year medical students were tested by IPE which included two components: objective structured practical examination (OSPE) and performance exercise (PE). Scores of each student of the study sample in PE and OSPE in the 4th block were analysed. Results and conclusion: Analysis of student scores in the examinations revealed that student performance in PE was better than that in OSPE for all three batches. The correlation coefficients between the marks on OSPE and PE were found to be poor for all three batches. There was a significant difference in the mean scores on OSPE for all three batches (P value=0.014). There was also a significant difference in the mean scores on PE for all three batches (P value=0.013). Analysis of student scores also exposed some of the deficiencies of PE and OSPE. Students have differing strengths and weaknesses and each component of IPE thus tests different aspects of knowledge, understanding and abilities.

A study of hypoglycemic and antioxidant activity of Aegle marmelos in alloxan induced diabetic rats.

The present study was performed to evaluate the hypoglycemic and antioxidant effect of aqueous extract of Aegle marmelos leaves (AML) on diabetic rats. Male albino rats were randomly divided into three groups: Group I: Control; Group II: Diabetic rats; and Group III: Diabetic rats administered AML. Glucose, urea and glutathione-S-transferase (GST) in plasma, glutathione (GSH) and malondialdehyde (MDA) levels in erythrocytes were estimated in all the groups at the end of four weeks. There was a decrease in blood glucose at the end of four weeks in group III animals compared with group II, however it did not reach the control levels. There was an increase in erythrocyte GSH and a decrease in MDA in group III as compared to group II. The plasma GST levels were raised in diabetic rats when compared to controls. In the group III animals, there was a decrease in GST as compared to group II. Owing to hypoglycemic and antioxidant properties, AML may be useful in the long-term management of diabetes.

Lipid peroxidation in different tissues: effect of high cholesterol and fish oil in the diet.

Malonyldialdehyde was measured in erythrocytes, aorta and spleen on feeding mice with high cholesterol diet in presence and absence of fish oil. Mice were grouped as: Group I: Control laboratory diet Group II: 0.16% cholesterol (sunflower oil) Group III: 1.16% cholesterol (sunflower oil) Group IV: 1.16% cholesterol (fish oil) After 7 weeks on their respective diets, erythrocytic, and splenic MDA levels were significantly higher in group III compared to controls. Also, MDA levels in aorta and spleen showed a significant increase in group IV males compared to group III males. However in group IV the erythrocyte MDA levels were almost equal to that in controls. This suggests that high cholesterol diet increases lipid peroxidation in erythrocytes, spleen and aorta. Addition of fish oil in the diet further increases lipid peroxidation in aorta and spleen, but not in the erythrocytes.