GM1

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GM1
Identifiers
CAS number	[37758-47-7]
PubChem	6434235
MeSH	G(M1)+Ganglioside
Properties
Molecular formula	C73H131N3O31
Molar mass	1546.82 g/mol
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

GM1 (monosialotetrahexosylganglioside) the "prototype" ganglioside, is a member of the ganglio series of gangliosides which contain one sialic acid residue. GM1 has important physiological properties and impacts neuronal plasticity and repair mechanisms, and the release of neurotrophins in the brain. Besides its function in the physiology of the brain, GM1 acts as the site of binding for both Cholera toxin and E. coli heat-labile enterotoxin (Traveller's diarrhea).^[1]

Antibodies to GM1 are increased in Guillain-Barré syndrome, dementia and lupus but their function is not clear.^[2] There is some evidence to suggest these antibodies are associated with diarrhoea in Guillain-Barré syndrome.^[3]

[edit] GM1 and the cholera toxin

The bacteria Vibrio cholerae ultimeric toxin called the cholera toxin. The A1 subunit of this toxin will gain entry to intestinal epithelial cells via the GM1 ganglioside receptor. Once inside, the A1 subunit will ADP ribosylate the Gs Alpha subunit which will prevent its GTPase activity. This will lock it in the active state and it will continuously stimulate adenylate cyclase. The sustained adenylate cyclase activity will lead to a sustained increase of cAMP which will cause electrolyte and water loss, causing diarrhea.^{[citation needed]}

Fortunately, the SGLT1 receptor is present in the small intestine. When the cholera patient is given a solution containing water, sodium and glucose, the SGLT1 receptor will reabsorb sodium and glucose, while water will be passively absorbed with the sodium. This will replace the water and electrolyte loss in the cholera induced diarrhea.

[edit] References