2006 Fiscal Year Final Research Report Summary
Studies on emetic signal pathway and molecular mechanism of staphylococcal enterotoxin
| Project/Area Number |
17590381
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Bacteriology (including Mycology)
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| Research Institution | Hirosaki University |
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Principal Investigator |
HU Dong-Liang Hirosaki University, School of Medicine, Associate Professor, 医学部, 助教授 (10333733)
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| Co-Investigator(Kenkyū-buntansha) |
NAKANE Akio Hirosaki University, School of Medicine, Professor, 医学部, 教授 (30164239)
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| Project Period (FY) |
2005 – 2006
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| Keywords | staphylococcal enterotoxin / emetic activity / cannabinoide / serotonin / house musk shrew |
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| Research 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. Pretreatment 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 CB 1 antagonist. Both 5-HT release and CB 1 receptor expression were found in the mucosal and myenteric plexus of the intestine. Moreover, a CB 1 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 down-regulated by the CB system through decreasing 5-HT release in intestine.
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Research Products
(12 results)
