Enhanced dendritic arborization of amygdala neurons during growth spurt periods in rats orally intubated with Bacopa monniera extract.

Bacopa monniera (BM)--a small, creeping herb-has been classified under Medhya rasayana (medicinal plants rejuvenating intellect and memory) in the ancient Indian system of medicine, viz., Ayurveda. Therefore, this plant has been investigated in several laboratories in India for its neuropharmacological effects. Here, we investigated the role of BM standardized extract on the dendritic morphology of amygdaloid neurons-one of the regions concerned with learning and memory. The rat pups (10 days old) were fed standardized extract of BM (20, 40 and 80 mg/kg) for 2, 4 and 6 weeks. After the treatment period, the rats were killed by decapitation, the brains were removed and amygdaloid neurons were impregnated with silver nitrate (Golgi staining). Amygdaloid neurons were traced using camera lucida. Dendritic branching points (a measure of dendritic arborization) and dendritic intersections (a measure of dendritic length) were quantified. These data were compared with control rats. The results showed a significant increase in dendritic length and dendritic branching points along the length of dendrites of the amygdaloid neurons of rats treated with all doses of BM for longer periods of time (i.e., 4 and 6 weeks). We conclude that constituents present in BM extract have neuronal dendritic growth stimulating properties.