| 词条 | Prostaglandin antagonist |
| 释义 |
A prostaglandin antagonist is a hormone antagonist acting upon one or more prostaglandins, a subclass of eicosanoid compounds which function as signaling molecules in numerous types of animal tissues. NSAIDs are perhaps the best-known prostaglandin antagonists; they suppress the signaling function of prostaglandins, which are important mediators of pain, fever, and inflammation responses, by inhibiting the cyclooxygenase enzymes and thereby reducing prostaglandin synthesis. Corticosteroids inhibit phospholipase A2 production by boosting production of lipocortin, an inhibitor protein. Relatively new drugs, known as COX-2 selective inhibitors or coxibs, are used as specific inhibitors of the COX-2 isoform of cyclooxygenase. The development of these drugs allowed the circumvention of the negative gastrointestinal side effects of NSAIDs while still effectively reducing inflammation. Adverse effectsBoth NSAIDs and coxibs have been shown to increase the risk of myocardial infarction when taken on a chronic basis for at least 18 months. One emerging hypothesis that may explain these cardiovascular effects is that coxibs create an imbalance in circulating TxA2 (thromboxane A2) and PGI2 (prostacyclin) levels. An increase in the ratio of TxA2/PGI2 could lead to increased platelet aggregation and dysregulation of platelet homeostasis.[1] See also
References1. ^Cheng Y et al., Role of prostacyclin in the cardiovascular response to thromboxane A2. Science. 2002. 296:539–51. {{PMID|11964481}}. External links
2 : Receptor antagonists|Prostaglandins |
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