Regulation of noradrenergic function by inflammatory cytokines and depolarization
Article first published online: 3 JUL 2003
Journal of Neurochemistry
Volume 86, Issue 3, pages 774–783, August 2003
How to Cite
Li, W., Knowlton, D., Woodward, W. R. and Habecker, B. A. (2003), Regulation of noradrenergic function by inflammatory cytokines and depolarization. Journal of Neurochemistry, 86: 774–783. doi: 10.1046/j.1471-4159.2003.01890.x
- Issue published online: 3 JUL 2003
- Article first published online: 3 JUL 2003
- Received April 3, 2003; revised manuscript received April 30, 2003; accepted May 1, 2003.
- norepinephrine uptake;
- sympathetic neuron;
- tumor necrosis factor alpha
Although the sympathetic neurons innervating the heart are exposed to the inflammatory cytokines cardiotrophin-1 (CT-1), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNFα) after myocardial infarction, the effects of these cytokines on noradrenergic function are not well understood. We used cultured sympathetic neurons to investigate the effects of these cytokines on catecholamine content, the tyrosine hydroxylase co-factor, tetrahydrobiopterin (BH4), and norepinephrine (NE) uptake. CT-1, but not IL-6 or TNFα, suppressed NE uptake and catecholamines in these neurons, whereas CT-1 and, to a lesser extent, IL-6 decreased BH4 content. CT-1 exerted these effects by decreasing tyrosine hydroxylase, GTP cyclohydrolase (GCH) and NE transporter mRNAs, while IL-6 lowered only GCH mRNA. The neurons innervating the heart are also activated by the central nervous system after myocardial infarction. We examined the combined effect of depolarization and cytokines on noradrenergic function. In CT-1-treated cells, depolarization caused a small increase in BH4 and NE uptake, and a large increase in catecholamines. These changes were accompanied by increased TH, GCH and NE transporter mRNAs. CT-1 and depolarization regulate expression of noradrenergic properties in an opposing manner, and the combined treatment results in elevated cellular catecholamines and decreased NE uptake relative to control cells.