Regional differences in the ultrastructure of purkinje cells of the rat.

In the albino rat, perikaryal diameter, volume density of the granular endoplasmic reticulum and Golgi apparatus, and lumenal diameter of cisternae of the granular endoplasmic reticulum are larger in Purkinje cells of lobule VIa (neocerebellum) than in those of lobule X (archicerebellum). In contrast, only the surface density of cisternae of the granular endoplasmic reticulum is larger in Purkinje cells of lobule X. The cisternae of granular endoplasmic reticulum are arranged into conspicuous Nissl bodies parallel to the nuclear membrane, but the content of ribosomes and polysomes is markedly less in lobule-X cells than in cells from lobule VIa. These results indicate qualitative and quantitative differences between the metabolically important organelles in Purkinje cells of the neo- and archicerebellum (cf. Larsell 1952).