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 postnatal 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 patterns of dendritic branching. Complex dendritic branching was evident with a progressive shift in peak branching peripherally. Lead-exposed Purkinje cells showed early sprouting with subsequent pruning. At 5 weeks of age dendritic branches on experimental cells were increased along the entire dendritic extent. Control Purkinje cells showed initial sprouting with subsequent pruning. Normal developmental growth spurts and lead-induced effects were evident on dendritic height, width and distance from the surface. Cerebella stained with hematoxylin and eosin and cresyl violet acetate showed no evidence of vascular damage or other pathologies. These findings corroborate the evidence of hyperspiny dendritic formation representing an important mechanism of neuronal plasticity. In regard to morphological effects of lead on rodents, the hyperspiny Purkinje cell dendrites and patterns of dendritic growth in lead-treated kittens offer an alternative interpretation of neurobehavioral findings of lead-burdened children. The results are discussed with reference to other aspects of lead exposure and neural development.