March 1, 1999Journal of Cardiovascular Pharmacology
Acute Simultaneous Stimulation of Nitric Oxide and Oxygen Radicals by Angiotensin II in Humans in Vivo
Why the study?
Does NO clamping or vitamin C coinfusion alter angiotensin II-induced vasoconstriction in healthy subjects?
Population
26 healthy subjects
Comparison
Intraarterial cumulative infusion of angiotensin… vs Angiotensin II infusion with saline
Design
Other
Authors
Discussion
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Implication
No immediate clinical implications in healthy subjects; leaves open mechanistic roles of NO and oxidative stress in disease states.
Key Points
- This research aims to investigate how angiotensin II influences blood flow through interactions with nitric oxide and superoxide in humans.
- Venous occlusion plethysmography was utilized to measure forearm blood flow in 26 healthy subjects during angiotensin II infusion.
- In 14 subjects, the effects of angiotensin II were examined with and without nitric oxide availability using L-NMMA and nitroprusside.
- In 12 other subjects, the interaction of angiotensin II with superoxide was assessed through co-infusion with vitamin C.
- During 'free' NO conditions, blood flow decreased from 2.70 to 1.38 ml/100 ml forearm/min (p<0.05).
- Vasoconstriction was enhanced during NO clamp, with blood flow decreasing from 2.56 to 1.19 ml/100 ml forearm/min (p<0.05).
- Vitamin C co-infusion significantly attenuated angiotensin II-induced vasoconstriction, with blood flow decreasing from 3.08 to 1.12 ml/100 ml forearm/min (p<0.05).
Structured PICO
Does NO clamping or vitamin C coinfusion alter angiotensin II-induced vasoconstriction in healthy subjects?
P
Population
26 healthy subjects
I
Intervention
Intraarterial cumulative infusion of angiotensin II with NO clamp (L-NMMA and nitroprusside) (n=14) or vitamin C coinfusion (n=12)
C
Comparator
Angiotensin II infusion with saline (free NO system / without vitamin C)
O
Outcome
Forearm blood flow measured by venous occlusion plethysmographysurrogate
Angiotensin II directly stimulates both endothelial nitric oxide and oxygen radicals in humans in vivo, modulating its own vasoconstrictor effects.
Cite This Study
Dijkhorst-Oei et al. (1999) studied this question.