Food Poisoning And Vagus Nerve
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The Vagus nerve, also known as pneumogastric nerve or cranial nerve X, is the only nerve that connects the brain to the remaining part of the body.
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It is the tenth cranial nerve that starts in the medulla oblongata, extends through the jugular foramen and runs down below the head, to the neck, chest and abdomen. The Vagus nerve is responsible for mediating various important functions inside the body including heart rate, abdominal muscle movement and the movement of food inside the stomach and intestine.
Stimulation of Vagus nerves occurs as a result of signals delivered by the brain. Another important way of stimulating Vagus nerve in the stomach lining and inducing emesis and diarrhea is through staphylococcal enterotoxins. These enterotoxins are released as a result of food poisoning caused due a gram positive bacterium known as Staphylococcus aureus. Staphylococcus is a non-spore forming, facultative anaerobic, non-motile bacterium that usually occurs in the form of clusters and belongs to a “cocci” group of bacteria. Staphylococcus is the most common cause of bacterial infections in humans. The bacterium exists in air, dust, sewage, water, milk, food, environmental surfaces and on mucous membranes and skin of humans and animals.
Disease is caused as a result of a variety of enterotoxins released by the bacterium. Some of these include the alpha toxins, beta toxins, gamma toxins, delta toxins and the superantigens. Along with these, another heat labile exotoxin released by Staphylococcus is the Toxic Shock Syndrome Toxin-1 (TSST-1).
Staphylococcal enterotoxins are superantigens that stimulate the Vagus nerve endings present in the lining of stomach and the intestine, thereby causing a dysregulated emetic response. As a result, food poisoning symptoms like nausea, cramps, vomiting and diarrhea appear immediately within 2-8hrs of ingesting contaminated food.
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