The effects of undernutrition on Purkinje cell dendritic growth in the rat.

The effects of undernutrition on the developing cerebellum were studied in 30-day-old rats undernourished from birth by restricting access to the lactating mother. These animals showed a significant reduction in cerebellar weight when compared with well-nourished controls. Quantitative studies of the cerebellar vermis revealed a 34.2% reduction in total area, with the density of both granule cells and Purkinje cells increased. Network analysis of Golgi-Cox preparations indicated a significant increase in the density of dendritic fields of Purkinje cells, although there was a 37% decrease in overall network size, due to reduction in the total number of dendritic segments, and a reduction in the length of distal segments. Topological analysis indicated that the network had developed by terminal branching, as in normal animals, but with some deviation from the usual purely random branching pattern. All the observed modifications may be accounted for in terms of alterations in protein synthesis and DNA synthesis occurring in undernourished animals. This leads to alterations in the extent of the interneuronal matrix, a reduction in the number of granule cells and direct effects on Purkinje cell metabolism, all of which influence dendritic development, although the relative importance of each of these factors awaits precise definition.