Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

By application of electron cytochemical techniques to cerebellar tissue, the presence of proteoglycans was demonstrated at the axoplasmic matrix of mossy fiber endings. Blocks of glutaraldehyde (G) fixed mouse cerebellum were processed according to the following procedures: a) Some pieces of tissue were post-fixed in osmium tetroxide, dehydrated by ethanol and embedded in araldite. b) Other pieces were sectioned to 30 mum thick and then immersed in Alcian blue solution pH = 2.7 followed by osmium tetroxide fixation, dehydrated and embedded in araldite (GABOUL procedure). c) Parallel slices of (b) previous to Alcian blue immersion were washed and incubated in either methanol-HCl, neuraminidase, ribonuclease or testicular hyaluronidase with their respective controls. d) Other blocks of G fixed tissue without any other treatment and fixation were dehydrated and embedded in araldite. Ultrathin sections of a, b and c were doubly stained with uranyl acetate and lead citrate while ultrathin sections of (d) were stained with the osmium coordination compound Os-DMEDA. The electron microscopic study revealed at the presynaptic axoplasm of mossy fiber rosettes, the presence of a GABOUL and Os-DMEDA positive electron dense material surrounding synaptic vesicles and continuous with presynaptic dense projections. This material which coincides with cytonet distribution was resistant to neuraminidase and ribonuclease and sensible to hyaluronidase and carboxymethylation. These findings permit us to conclude that the axoplasmic material of mossy fiber endings is constituted by proteoglycans in which hyaluronic acid and chondroitin 4-and/or 6-sulphate are present. The probable importance of these proteoglycans in synaptic mechanisms is also discussed.
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PMID:Electron microscopic demonstration of hyaluronidase sensible proteoglycans at the presynaptic area in mouse cerebellar cortex. 6 92

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.
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PMID:Histochemical demonstration of cytoplasmic glycosaminoglycans in the macroneurons of the human central nervous system. 670 30