Absence of brain spectrin(240/235) in dendrites of mammalian brain.

Spectrin is a major cytoskeletal component of the brain. At least 3 distinct spectrin subtypes are found in mammalian brain: brain spectrin(240/235) which is confined mainly to axons, brain spectrin(240/235E) which is localized largely in neural cell bodies and dendrites, and brain spectrin(240/235A) which is associated only with astrocytes. Recently, Ivy et al. reported that brain spectrin (240/235) was located in dendrites when tissues were fixed with 4% paraformaldehyde. To evaluate this matter further, rat cerebellar cortex prepared with and without aldehydes was stained with antibodies to brain spectrin(240/235) and examined using peroxidase (4-chloro-1-naphthol or avidin-biotin) or rhodamine to visualize the primary antibody. The preparations (10 microns and 40 microns sections) showed that brain spectrin(240/235) resided largely in axons with occasional staining of neuronal soma (Purkinje cells), but was not observed in dendrites. These results confirm earlier reports [e.g., (10,12)] showing the discrete compartmentalization of brain spectrin(240/235) in axons and cell bodies.