Abstract
Sialic acid is an acidic monosaccaride and plays crucial roles in various membrane functions in mammalian central nervous systems. Sialidase removes sialic acid from sialoglycoconjugates and also plays crucial roles in many neural functions, including differentiation and maturation of neurons and learning and memory. Recently, we visualized extracellular sialidase activity on the membrane surface in the rat brain by using a highly sensitive fluorescent histochemical method. Myelin-abundant regions showed intense fluorescence in the rat brain. Although the hippocampus showed weak fluorescence in the brain, mossy fiber terminals in the hippocampus showed relatively intense fluorescence. In this review, we describe the distribution of sialidase activity in the brain and discuss the role of sialidase in myelin and the hippocampus.
