Ultrastructural and carbohydrate histochemical study of the Vater-Pacini corpuscles in the digital pads of the North American raccoon (Procyon lotor with special regard to basic function

摘要

Numerous and very large Vater-Pacini corpuscles were observed in the forefoot digital pads of the North American raccoon (Procyon lotor). In addition to ultra-structure, the distribution and selectivity of complex glycoconjugates in this sensory corpuscle type were examined by carbohydrate histochemical techniques, in particular lectin histochemistry. The Vater-Pacini corpuscles present showed the typical lamellar structure known for mammals and contained high amounts of neutral and acidic glycoconjugates with various saccharide residues (aphal -L-fucose, beta -D-galactose, sialic acid) in a specific intracorpuscular distribution pattern, including variations between the outer lamellae and the inner core. The results obtained are discussed with regard to possible functions of the Vater-Pacini corpuscles found in the raccoon forefoot pads. The corpuscular glycoconjugate components may furnish a high and differentiated viscoelasticity for rapid pressure transmission within the large Vater-Pacini corpuscles. Thus, the digital pads of the forepaws can be considered as part of aspecific mechanoreceptor system related to excellent object manipulation properties in this mammalian species.