An electron microscopic and radioautographic study on experimental kernicterus. II. Bilirubin movement within neurons and release of waste products via astroglia.

Response of the neurons to bilirubin in asphyxiated newborn rabbits was studied in vivo with the use of the electron microscope and radioautographic technics. A morphologic basis for the mode of intraneuronal bilirubin movement in kernicterus has been established. The absorbed bilirubin had ready access to the Golgi complex from the dendrite through the neurotubules by a mechanism of centripetal dendroplasmic flow. The endoplasmic reticulum provided a subcellular canalicular system for the directed passage from the Golgi complex to the nuclear membrane. Proximodistal flow of bilirubin in the axoplasm caused spotty destruction of axons. The release of waste products from the affected neurons toward the capillaries is very likely an effect of reverse transastroglial transport.