Effect of chlorpromazine on Purkinje cell growth patterns

The phenothiazine, chlorpromazine, when administered perinatally to rats is implicated in the production of both motor and behavioural deficits. In this study the effects of chlorpromazine on dendritic growth of cerebellar Purkinje cells were examined after administering the drug to litters of Long-Evans hooded rats from 18 days postcoitus to 21 days postnatum. Various parameters of Purkinje cell growth were analysed at specific times after treatment utilizing Golgi-prepared specimens. Granule cell density was used as an estimate of parallel fibre numbers. When compared with control Purkinje cells the treated cells at 7 weeks postnatum had established longer segments and increased mean vertex path length. The total number of segments was also increased and the distribution of segments of different orders was abnormal. In addition, the spines on terminal dendritic branches were both longer and of increased density in the chlorpromazine-treated group. These observations confirm that chlorpromazine produces distinct morphological alterations in mature Purkinje cells.