Lectin and proteoglycan histochemistry of feline Pacinian corpuscles

We studied carbohydrate residues of glycoproteins and proteoglycans (PGs) i n peritoneal Pacinian corpuscles of five adult cats. Terminal monosaccharid es of glycoproteins and related polysaccharides were identified by lectin h istochemistry and the PGs and glycosaminoglycans (GAGs) by specific antibod ies. The most intensive lectin staining reactions indicated an abundance of glycoconjugates with terminal mannose (Man) or sialic acid residues, but n o complex-type oligosaccharides were detected within the corpuscles. Termin al fucose (Fuc) and galactose (Gal) residues typical for O-linked mucin-typ e glycoproteins generally associated with high water binding capacity were also absent. Antibodies against unsulfated chondroitin (C-0-S), chondroitin -4-sulfate (C-4-S), and decorin showed positive reactions in the interfibri llar spaces between the lamellae, around collagen fibers, and around the la mellae of the perineural capsule, especially in the outer parts known to co ntain Type II collagen. Biglycan showed a preference for the innermost part of the perineural capsule (intermediate layer), known to contain Type V co llagen. Collagen V and biglycan are both linked to growth processes. Hyalur onic acid (HA), chondroitin-6-sulfate (C-6-S) chains, and a chondroitin sul fate proteoglycan (CSPG) were colocalized in the terminal glia. The study o f carbohydrates with high water binding capacity may contribute to our unde rstanding of the high viscoelasticity of Pacinian corpuscles.