Purkinje cells in the adult cat cerebellar cortex possess a perineuronal net of proteoglycans

The Purkinje cells in the adult cat cerebellar cortex were found to possess proteoglycans proteoglycans which could be stained with our fine cationic iron colloid and Fujita's highly concentrated aldehyde fuchsin, and digeste d by chondroitinase ABC/keratanase/heparitinase and hyaluronidase. The Purk inje cells are surrounded by some collagenous elements which are stained wi th Gomori's ammoniacal silver and digested by collagenase, The Purkinje cel ls also express nerve cell surface glycoproteins which are labeled with lec tin Vicia villosa agglutinin and digested by a double treatment with collag enase and endo-alpha-N-acetylgalactosaminidase. Sole digestion by endo-alph a-N-acetylgalactosaminidase never erased the lectin labeling of the nerve c ell surface glycoproteins. These findings suggest that the collagenous elem ents mediate the linkage of the perineuronal proteoglycans to the nerve cel l surface glycoproteins. It is presumed that in mice and rats, the perineur onal nets of proteoglycans and nerve cell surface glycoproteins of the Purk inje cells are so thin or coarse that they can not be sufficiently visualiz ed under the light microscope.