title: Staphylococcal enterotoxin induces emesis through increasing serotonin release in intestine and it is downregulated by cannabinoid receptor 1.
abstract: Staphylococcal enterotoxins (SEs) produced by Staphylococcus aureus are the most recognizable bacterial superantigenic toxins causing food poisoning in humans throughout the world. However, it remains unclear how SEs induce emesis and its emetic signal pathway. We investigated a mechanism of SEA-induced emesis using a small emetic animal model, house musk shrew. SEA-induced emesis in the animals was inhibited by a 5-hydroxytryptamine (5-HT) synthesis inhibitor and a 5-HT(3) receptor antagonist. SEA could increase 5-HT release in the small intestine. Pre-treatment with 5,7-dihydroxytryptamine (5,7-DHT) markedly inhibited SEA-induced emesis. SEA-induced emesis was also abolished by surgical vagotomy. Furthermore, cannabinoid (CB) receptor agonists inhibited SEA-induced emesis, and the action was reversed by a CB1 antagonist. Both 5-HT release and CB1 receptor expression were found in the mucosal and myenteric plexus of the intestine. Moreover, a CB1 receptor agonist significantly decreased the 5-HT release in the intestine. These results demonstrate that SEA induces 5-HT release in intestine, rather than in brain, and that the 5-HT(3) receptors on vagal afferent neurons are essential for SEA-stimulated emesis. In addition, SEA-induced emesis is downregulated by the CB system through decreasing 5-HT release in intestine.
authors.affiliation: Department of Microbiology and Immunology, Hirosaki University School of Medicine, Hirosaki, Japan.
authors.forename: Dong-Liang
authors.initials: DL
authors.lastname: Hu
authors.forename: Gang
authors.initials: G
authors.lastname: Zhu
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Mori
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Omoe
authors.forename: Motohiro
authors.initials: M
authors.lastname: Okada
authors.forename: Koichi
authors.initials: K
authors.lastname: Wakabayashi
authors.forename: Sunao
authors.initials: S
authors.lastname: Kaneko
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Shinagawa
authors.forename: Akio
authors.initials: A
authors.lastname: Nakane
mesh_terms: D015116:5,7-Dihydroxytryptamine / Q000378:metabolism; D000818:Animals; D003714:Denervation; D015536:Down-Regulation; D004768:Enterotoxins / Q000378:metabolism*; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D043884:Receptor, Cannabinoid, CB1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D044406:Receptors, Serotonin, 5-HT3 / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism*; D018490:Serotonin Agents / Q000378:metabolism; D012702:Serotonin Antagonists / Q000378:metabolism; D012788:Shrews; D013211:Staphylococcus aureus / Q000378:metabolism / Q000472:pathogenicity; D014630:Vagus Nerve / Q000601:surgery; D014839:Vomiting / Q000378:metabolism*
chemical_list: D004768:Enterotoxins; D043884:Receptor, Cannabinoid, CB1; D044406:Receptors, Serotonin, 5-HT3; D018490:Serotonin Agents; D012702:Serotonin Antagonists; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin