Surface glycoconjugates in the olfactory system of Ambystoma mexicanum

Abstract

Lectin binding histochemistry was performed on the olfactory system of neotenic and metamorphosed Ambystoma mexicanum to investigate the distribution and density of defined carbohydrate residues on the cell surface glycoproteins of the olfactory and vomeronasal receptor cells and their terminals in the olfactory bulbs. The lectin binding patterns indicate that the main olfactory system possesses a high density of N-acetyl-galactosamine and N-acetyl-glucosamine residues, while the vomeronasal system contains a high density of N-acetyl-galactosamine and galactose moieties and a moderate density of N-acetyl-glucosamine. The presence of specific glycoproteins, whose terminal sugars are detected by lectin binding, might be related to the chemoreception and transduction of the odorous message into a nervous signal or to the histogenesis and development of the olfactory system. In fact, the olfactory and vomeronasal receptor cells are neurons that undergo a continuous cycle of proliferation not only during development but also in mature animals.