Dendritic alterations of cerebellar Purkinje neurons in postnatally lead-exposed kittens

Many investigations have sought to determine the effect of lead exposure on the development of the cerebellum. This study addresses the effects of pos tnatal lead exposure in kittens on dendritic development of Purkinje cells. Golgi-Cox filled cells were used to measure dendritic branching patterns, spine density, height, width and distance from the cerebellar surface. The results revealed a significant increase in spine density and altered patter ns of dendritic branching. Complex dendritic branching was evident with a p rogressive shift in peak branching peripherally. Lead-exposed Purkinje cell s showed early sprouting with subsequent pruning. At 5 weeks of age dendrit ic branches on experimental cells were increased along the entire dendritic extent. Control Purkinje cells showed initial sprouting with subsequent pr uning. Normal developmental growth spurts and lead-induced effects were evi dent on dendritic height, width and distance from the surface. Cerebella st ained with hematoxylin and eosin and cresyl violet acetate showed no eviden ce of vascular damage or other pathologies. These findings corroborate the evidence of hyperspiny dendritic formation representing an important mechan ism of neuronal plasticity. In regard to morphological effects of lead on r odents, the hyperspiny Purkinje cell dendrites and patterns of dendritic gr owth in lead-treated kittens offer an alternative interpretation of neurobe havioral findings of lead-burdened children. The results are discussed with reference to other aspects of lead exposure and neural development. Copyri ght (C) 2000 S. Karger AG, Basel.