Nuclear inclusions in immature glial cells of the rat hypothalamus during the postnatal period.

Ultrastructural study of the hypothalamic ventromedial nucleus during the postnatal period showed the presence of nuclear inclusions in immature glial cells. These inclusions, identified as "coiled bodies", consist of round-to-oval formations of coiled electron-dense strands embedded in a less dense fibrillar matrix. Coiled bodies are located free within the nucleoplasm, showing no specific relationships with the nucleolus or the nuclear membrane. The cells containing coiled bodies were typified as oligodendrocyte precursors, mainly oligodendroblasts. The coiled bodies were not found in mature glial cells nor in other types of immature glial elements. The nature and possible functional role of coiled bodies are suggested in the light of recent morphological and biochemical data.