title: Mitochondria in the postnatally developing rat cerebellar cortex: a morphological and biochemical study.
abstract: Ultrastructural changes during development in the proliferating cells of the external granular layer and the granule cells of the internal granular layer of the rat cerebellar cortex were examined. Changes in the number of free ribosomes, development of membrane systems, nuclear appearance and the number of cristae and matrix density of mitochondria suggested that both the round and elongated cells of the external granular layer and the granule cells of the internal granular layer were at same stage of maturation at any given age. Quantitatively, the relative volumes of cytoplasm and of mitochondria in the granule cells of internal granular layer were significantly higher than in the proliferating external granular layer cells; however, mitochondrial density and its increase during development were not significantly different in the two cell populations. The activity of the mitochondrial enzyme, succinate dehydrogenase, was also similar in ultrastructurally preserved and metabolically competent perikaryal fractions enriched in replicating external granular layer cells, granule cells and Purkinje cells. These findings emphasize the similarities between proliferating external granular layer cells and granule cells of internal granular layer. They lend support to the view that these cell types at the ages examined, represent a continuum of maturation towards full neuronal differentiation.
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002525:Cerebellar Cortex / Q000201:enzymology / Q000254:growth & development / Q000648:ultrastructure*; D008854:Microscopy, Electron; D008928:Mitochondria / Q000201:enzymology / Q000648:ultrastructure*; D009474:Neurons / Q000166:cytology; D051381:Rats; D013385:Succinate Dehydrogenase / Q000378:metabolism
chemical_list: D013385:Succinate Dehydrogenase