Abstract
Experiments were conducted to test the hypothesis that hypertension produced by chronic ET-1 infusion is mediated by NADPH oxidase-dependent superoxide production. Mean arterial pressure (MAP) was continuously monitored in male Sprague Dawley rats by telemetry. After baseline measurements, rats were placed on a high-salt diet (8% NaCl) and osmotic minipumps were implanted to infuse ET-1 (5 pmol/kg per minute intravenous) for 12 days. Control rats were maintained on the high-salt diet only. Separate groups of rats were also infused with ET-1 and given the superoxide dismutase mimetic, tempol (1 mmol/L), or the NADPH oxidase inhibitor, apocynin (1.5 mmol/L), in the drinking water. Infusion of ET-1 significantly increased MAP when compared with baseline values (132±3 versus 114±2 mm Hg, P<0.05). Neither tempol nor apocynin treatment had any effect on the increase in MAP produced by ET-1 when compared with baseline values (127±5 versus 113±2 and 130±3 versus 115±2 mm Hg, respectively). Plasma 8-isoprostane, an indicator of oxidative stress, was significantly increased in ET-1-infused rats compared with rats on a high-salt diet alone (128±33 versus 51±5 pg/mL; P<0.05). Both tempol and apocynin treatment significantly attenuated the ET-1-induced increase in plasma 8-isoprostane (72±10 and 61±6 pg/mL, respectively). Similarly, ET-1 infusion also significantly increased aortic superoxide production (chemiluminescence and dihydroethidium staining techniques), which was prevented by both tempol and apocynin. These data provide evidence that chronic ET-1 infusion increases vascular NADPH oxidase-dependent superoxide production but does not account for chronic ET-1-induced hypertension.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 283-287 |
| Number of pages | 5 |
| Journal | Hypertension |
| Volume | 45 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 1 2005 |
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Keywords
- Endothelin
- Oxidative stress
- Sodium
ASJC Scopus subject areas
- Internal Medicine
Cite this
NADPH oxidase inhibition attenuates oxidative stress but not hypertension produced by chronic ET-1. / Elmarakby, Ahmed Abdelrazik; Loomis, E. Dabbs; Pollock, Jennifer S.; Pollock, David M.
In: Hypertension, Vol. 45, No. 2, 01.02.2005, p. 283-287.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - NADPH oxidase inhibition attenuates oxidative stress but not hypertension produced by chronic ET-1
AU - Elmarakby, Ahmed Abdelrazik
AU - Loomis, E. Dabbs
AU - Pollock, Jennifer S.
AU - Pollock, David M.
PY - 2005/2/1
Y1 - 2005/2/1
N2 - Experiments were conducted to test the hypothesis that hypertension produced by chronic ET-1 infusion is mediated by NADPH oxidase-dependent superoxide production. Mean arterial pressure (MAP) was continuously monitored in male Sprague Dawley rats by telemetry. After baseline measurements, rats were placed on a high-salt diet (8% NaCl) and osmotic minipumps were implanted to infuse ET-1 (5 pmol/kg per minute intravenous) for 12 days. Control rats were maintained on the high-salt diet only. Separate groups of rats were also infused with ET-1 and given the superoxide dismutase mimetic, tempol (1 mmol/L), or the NADPH oxidase inhibitor, apocynin (1.5 mmol/L), in the drinking water. Infusion of ET-1 significantly increased MAP when compared with baseline values (132±3 versus 114±2 mm Hg, P<0.05). Neither tempol nor apocynin treatment had any effect on the increase in MAP produced by ET-1 when compared with baseline values (127±5 versus 113±2 and 130±3 versus 115±2 mm Hg, respectively). Plasma 8-isoprostane, an indicator of oxidative stress, was significantly increased in ET-1-infused rats compared with rats on a high-salt diet alone (128±33 versus 51±5 pg/mL; P<0.05). Both tempol and apocynin treatment significantly attenuated the ET-1-induced increase in plasma 8-isoprostane (72±10 and 61±6 pg/mL, respectively). Similarly, ET-1 infusion also significantly increased aortic superoxide production (chemiluminescence and dihydroethidium staining techniques), which was prevented by both tempol and apocynin. These data provide evidence that chronic ET-1 infusion increases vascular NADPH oxidase-dependent superoxide production but does not account for chronic ET-1-induced hypertension.
AB - Experiments were conducted to test the hypothesis that hypertension produced by chronic ET-1 infusion is mediated by NADPH oxidase-dependent superoxide production. Mean arterial pressure (MAP) was continuously monitored in male Sprague Dawley rats by telemetry. After baseline measurements, rats were placed on a high-salt diet (8% NaCl) and osmotic minipumps were implanted to infuse ET-1 (5 pmol/kg per minute intravenous) for 12 days. Control rats were maintained on the high-salt diet only. Separate groups of rats were also infused with ET-1 and given the superoxide dismutase mimetic, tempol (1 mmol/L), or the NADPH oxidase inhibitor, apocynin (1.5 mmol/L), in the drinking water. Infusion of ET-1 significantly increased MAP when compared with baseline values (132±3 versus 114±2 mm Hg, P<0.05). Neither tempol nor apocynin treatment had any effect on the increase in MAP produced by ET-1 when compared with baseline values (127±5 versus 113±2 and 130±3 versus 115±2 mm Hg, respectively). Plasma 8-isoprostane, an indicator of oxidative stress, was significantly increased in ET-1-infused rats compared with rats on a high-salt diet alone (128±33 versus 51±5 pg/mL; P<0.05). Both tempol and apocynin treatment significantly attenuated the ET-1-induced increase in plasma 8-isoprostane (72±10 and 61±6 pg/mL, respectively). Similarly, ET-1 infusion also significantly increased aortic superoxide production (chemiluminescence and dihydroethidium staining techniques), which was prevented by both tempol and apocynin. These data provide evidence that chronic ET-1 infusion increases vascular NADPH oxidase-dependent superoxide production but does not account for chronic ET-1-induced hypertension.
KW - Endothelin
KW - Oxidative stress
KW - Sodium
UR - http://www.scopus.com/inward/record.url?scp=13144293998&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=13144293998&partnerID=8YFLogxK
U2 - 10.1161/01.HYP.0000153051.56460.6a
DO - 10.1161/01.HYP.0000153051.56460.6a
M3 - Article
VL - 45
SP - 283
EP - 287
JO - Hypertension
JF - Hypertension
SN - 0194-911X
IS - 2
ER -