Histochemical demonstration of cytoplasmic glycosaminoglycans in the macroneurons of the human central nervous system

Abstract

The presence of glycosaminoglycans (GAG) has been histochemically demonstrated in the CNS of various mammalian species. They have been related with some nerve functions as neurotransmitters storage and synaptic transmission. In the present paper, the histochemical properties of nerve cell cytoplasmic GAG were studied in several regions of adult human CNS. Samples of brain cortex, pons, upper medulla, and cerebellar cortex obtained by autopsy from subjects not dying after neurological diseases were fixed by immersion in glutaraldehyde, dehydrated with ethanol, and embedded in paraffin. The sections were stained with Alcian blue solutions adjusted to pH 2.5, 4.0, and 5.7. To the latter solution MgCl2 was added in increasing concentration from 0.05 to 1.2 M. Testicular hyaluronidase, neuraminidase, and ribonuclease were applied on simultaneous sections with their respective controls. The sequence of these reactions allowed us to demonstrate the presence of hyaluronic acid along chondroitin-4- and/or 6-sulphate in the cytoplasm of most nerve cells. The sulphated GAG showed certain variability in the various regions studied related specially with their grade of sulphation.

Fixed negative charge and the Donnan effect: a description of the driving forces associated with brain tissue swelling and oedema

“…While GAGs may not represent the entirety of the FCD found within brain (other contributions may come from negatively charged DNA, proteins and matrix molecules), there is a significant amount of different sulphated proteglycans in brain, the majority of which contain chondroitin sulphate (Margolis et al 1975(Margolis et al , 1976Jenkins & Bachelard 1988;Lander 1993;Koppe et al 1997;Costa et al 2007). Much of this sulphated GAG, especially at later stages of development, has been localized within the cytoplasm of neurons and astrocytes (Margolis et al 1979;Alvarado & Castejon 1984;Aquino et al 1984;Sames & Hoyer 1992). GAG content measured with the DMMB assay for dead tissue exposed to different ionic solutions (200, 300, 2000 mOsm) was converted to FCD using equation (2.2) (figure 5a).…”

Glycosaminoglycans in Cortical Autopsy Samples from Alzheimer Brain

“…The gel properties of hydrated HA in the brain would be expected to restrict the diffusion of water and solutes such as proteins (Laurent, 1964). In addition, the polyanionic nature of HA and of chondroitin sulphate, which appears to be an intracellular GAG in mature rat brain (Margolis et al, 1979;Aquino et al, 1984) and probably in human brain also (Alvarado and Castejon, 1984), may contribute to the electrical properties of intra-and extracellular environments. For example, they may constitute a "sink" for cations such as Ca2+, Na', and K+.…”

Axonal transport of proteoglycans to the goldfish optic tectum

“…Localization of some proteoglycans within or on the surface of neurons has been deduced from the susceptibility of neuronal staining by Alcian blue to hyaluronidase treatment (12). In addition, antibodies to rat brain chondroitin sulfate proteoglycan (13) and PC12 cell heparan sulfate proteoglycan (14) are found to bind to neurons of rat brain and superior cervical ganglion respectively.…”