Immunohistological localization of N-acetylindolealkylamines in pineal gland, retina and cerebellum

An immunohistological method has been used for visualization of N-acetylindolealkylamines (N-acetylindoles) in the pineal gland, retina and cerebellum using antibody highly specific for two N-acetylindoles; namely, N-acetylserotonin and melatonin. Staining by a double antibody technique using fluorescein or peroxidase labeling revealed that N-acetylindole is present not only in the parenchymal cells of the pineal gland but also in the outer nuclear layer of the retina and in the granule and Golgi II cells of cerebellum. Because N-acetylindole was found in the retina and cerebellum even after pinealectomy, we can speculate that extrapineal biosynthesis of N-acetylindole may occur. The observation of staining for N-acetylindole in cerebellum of rat, rhesus monkey and man suggests that N-acetylindolealkylamines may be present in the central nervous tissue of all mammals.