| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 From Cardiology Unit, Department of Medicine, University of Rochester, Rochester, NY, USA; Department of Radiation Oncology, University of Rochester, Rochester, NY, USA
2 From Cardiology Unit, Department of Medicine, University of Rochester, Rochester, NY, USA
* To whom correspondence should be addressed. E-mail: chang-seng_liang{at}urmc.rochester.edu.
Cardiac norepinephrine (NE) uptake activity is reduced in congestive heart failure. Our studies in intact animals suggest that this effect on the cardiac sympathetic nerve endings is caused by oxidative stress and/or NE toxic metabolites derived from NE. In this study, we investigated the direct effects of NE on neuronal NE uptake activity and NE transporter (NET), using undifferentiated PC12 cells. Cells were incubated with NE (1-500 µM) either alone or in combination of cupric sulfate (1 µM), which promotes free radical formation by Fenton reaction, for 24 h. NE uptake activity was measured using [3H]NE. Cell viability was determined using trypan blue exclusion and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay, and cellular oxidative stress by dichlorodihydrofluorescein fluorescence and the reduced to oxidized glutathione (GSH/GSSG) ratio. Cell viability was reduced by NE >100 µM. At lower doses, NE produced oxidative stress and a dose-dependent reduction of NE uptake activity without affecting cell viability significantly. Cu++ , which has no direct effect on NE uptake activity, potentiated oxidative stress and reduction of NE uptake activity produced by NE. This decrease of NE uptake activity was associated with reductions of NE uptake binding sites and NET protein expression using the radioligand assay and Western blot, but no changes in NET gene expression. In addition, free-radical scavenger mannitol, and antioxidant enzymes superoxide dismutase and catalase reduced oxidative stress and attenuated the reductions of NE uptake activity and NET protein produced by NE/Cu. Thus, our results support a functional role of oxidative stress in mediating the neuronal NE uptake reducing effect of NE and that this effect of NE on NET is a post-transcriptional event.
This article has been cited by other articles:
|
|
 |
|
  R. Kvetnansky, E. L. Sabban, and M. Palkovits Catecholaminergic Systems in Stress: Structural and Molecular Genetic Approaches Physiol Rev, April 1, 2009; 89(2): 535 - 606. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. Mao, C. Iwai, P. C. Keng, R. Vulapalli, and C.-s. Liang Norepinephrine-induced oxidative stress causes PC-12 cell apoptosis by both endoplasmic reticulum stress and mitochondrial intrinsic pathway: inhibition of phosphatidylinositol 3-kinase survival pathway Am J Physiol Cell Physiol, May 1, 2006; 290(5): C1373 - C1384. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C.-s. Liang, W. Mao, C. Iwai, S. Fukuoka, and S. Y. Stevens Cardiac sympathetic neuroprotective effect of desipramine in tachycardia-induced cardiomyopathy Am J Physiol Heart Circ Physiol, March 1, 2006; 290(3): H995 - H1003. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Mao, C. Iwai, F. Qin, and C.-s. Liang Norepinephrine induces endoplasmic reticulum stress and downregulation of norepinephrine transporter density in PC12 cells via oxidative stress Am J Physiol Heart Circ Physiol, May 1, 2005; 288(5): H2381 - H2389. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
