Carbohydrates of the Vestibular End Organs Detected by Lectins

Abstract

The presence of carbohydrates was investigated in the vestibular end organs of the guinea pig using FITC-lectins. The following sugars have been identified: N-acetyl-glucosamine, galactose, mannose and fucose. In contrast, N-acetyl-galactosamine was not clearly detected. These sugars were suggested to be closely related to the formation and maintenance of otoconia as well as of the cupula. N-acetyl-glucosamine was considered to be the major component of the glycocalyx and also suggested to have a function as an anchoring structure between the epithelial cell and the otolithic membrane or the cupula.

Carbohydrates of the Vestibular End Organs

“…Lectins have been used to detect specific sugar com ponents in the inner ear in recent years [8][9][10]. In the vestibular end organs, N-acetylglucosamine, sialic acid, galactose, mannose and fucose have been found in the otoconia, the subotoconial membrane, the cupula and the subcupular meshwork [8,10].…”

“…In the vestibular end organs, N-acetylglucosamine, sialic acid, galactose, mannose and fucose have been found in the otoconia, the subotoconial membrane, the cupula and the subcupular meshwork [8,10]. In the glycocalyx, the presence of N-acetylglucosamine, sialic acid, mannose and galactose has been indicated by the use of lectins [9,10]. These studies, however, have been performed mainly at the light-microscopic level.…”

“…In this study, three types of lectins, WGA, Con A and APA, were utilized in order to detect certain individual sugar components, since our previous investigations had revealed that the glycocalyx of the vestibular end organs was intensely stained by these lectins [10].…”

“…In an effort to analyze and detect the specific sugar components in the inner ear, lectins have been recently introduced [8][9][10], Lectins, i.e. proteins and glycopro teins derived from both plants and animals, have the unique ability to bind to specific carbohydrate residues of mammalian glycoconjugates.…”

“…proteins and glycopro teins derived from both plants and animals, have the unique ability to bind to specific carbohydrate residues of mammalian glycoconjugates. This capacity has made it possible to detect individual sugar components in structures such as the glycocalyx [11], In the vestibular end organs, glucosamine, galactose, mannose and fucose have been noticed in the otoconia and cupula by the use of fluorescein-isothiocyanate-labeled lectins [8,10]. However, the precise localization and the functional sig nificance of the sugar components still remain unclear.…”