Abstract
Surface changes in the epithelium of the choroid plexuses of the lateral and third ventricles of rats induced by chronic administration of acetazolamide have been studied by scanning electron microscopy. After 3 weeks atrophic changes were evident, the microvilli and blebs normally seen on the ventricular surface of the cells appeared attenuated, and in extreme cases they disappeared, leaving the cell surface completely denuded. Localized areas of hypertrophy, indicated by secondary spherical budding, were occasionally observed. The atrophic changes accord with the known inhibitory effects of acetazolamide on CSF formation: perhaps the small number of cells undergoing hypertrophy compensate to some extent for the atrophic ones and maintain some CSF secretion.