Effects of norepinephrine (NE) on macrophage cytokine release are complex because the cells have both α2 and β2 adrenergic receptors, which mediate opposing actions. Furthermore, β2-adrenergic agonists are reported to have both stimulatory and inhibitory effects on interleukin-6 (IL-6). This study was designed to clarify the autocrine role of macrophage-derived NE on IL-6 production in activated peritoneal macrophages. Effects of NE on IL-6 production in the RAW264.7 macrophage cell-line also were investigated. Treatment of activated peritoneal macrophages with endotoxin, the α2-adrenergic antagonists yohimbine or RS79948 revealed that the α2-adrenergic receptor mediates a stimulatory autocrine action of catecholamines on IL-6 production. When peritoneal macrophages were treated with the β2 antagonist ICI-118,551 (ICI), there was both inhibition and stimulation of IL-6. Treatment of RAW264.7 macrophages with high and low concentrations of NE and various concentrations of ICI provided evidence that the concentration of NE determines whether the β2-adrenergic receptor mediates stimulation or inhibition of IL-6 production.
| Identifer | oai:union.ndltd.org:vcu.edu/oai:scholarscompass.vcu.edu:etd-2126 |
| Date | 01 January 2006 |
| Creators | Poe, Shaunta D. |
| Publisher | VCU Scholars Compass |
| Source Sets | Virginia Commonwealth University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | © The Author |
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