Pigments-Purkinje Cells

The enzymatic degradation of endocytosed material is often incomplete.

Vesicles and vacuoles with such material are called residual bodies . Lipofuscin is a membrane-enclose d, indigestible residue that is left over after lysosomal degradation. Lipofuscin-loaded residual bodies are called lipofuscin granules. In long-live d muscle and nerve cells, lipofuscin granules b ecome more abundant with age. Lipofuscin is therefore known as an aging or “wear-and-tear” pigment.  Lipofuscin granules in Purkinje cells from rat cerebellum. The small lipofuscin granules show an endogenous yellow fluorescence. They appear in small piles at the upper cell pole between nucleus and dendrite. Small granules can occur anywhere in the perikaryon.

Stain: Einarson gallocyanine; fluorescence microscopy (BG-12 excitation filter, 530-nm barrier filter); magnification: × 1000

This figure shows the ultrastructure of a lipofuscin granule. Note the bizarre shape (lipofuscin has an irregular surface), the osmiophilic electron-dense matrix, which consists of numerous very small granules, and the differences in electron densities. In the immediate vicinity of the granule, there are areas with polysomes 1 as well as short ergastoplasmic lamellae 2.

1 Polysomes

2 Nissl bodies

References

Kuehnel, W.(2003). Color Atlas of Cytology, Histology, and Microscopic Anatomy. 4^th edition . Institute of Anatomy Universitätzu Luebeck Luebeck, Germany . Thieme Stuttgar t · New York .