Effects of acute nitric oxide synthase inhibition on lower leg vascular function in chronic tetraplegia.
OBJECTIVE
To improve our understanding of the lower-leg vascular responses of nitric oxide synthase inhibition in persons with tetraplegia.


METHODS
Six people with chronic tetraplegia and 6 age-matched controls.


METHODS
Lower-leg relative vascular resistance and venous volume variation were obtained by venous occlusion plethysmography and blood pressure by auscultation at baseline. Postintravenous infusion of the nitric oxide synthase inhibitor NG-nitro-L-arginine-methyl-ester (1 mg x kg(-1) or placebo on separate days.


RESULTS
At baseline in the group with tetraplegia compared with controls, mean arterial pressure and relative vascular resistance of the leg were significantly lower. After nitric oxide synthase inhibition, mean arterial pressure and lower leg vascular resistance were significantly elevated in both groups. There were no group or intervention differences in venous volume variation.


CONCLUSIONS
These preliminary results suggest that nitric oxide synthase inhibition with 1 mg x kg(-1) N(G)-nitro-L-arginine-methyl-ester normalizes seated blood pressure and lower leg vascular resistance to control group baseline levels.
La Fountaine
Michael F
MF
VA Center of Excellence on the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, SCI Room 1E-02, 130 W. Kingsbridge Road, Bronx, NY 10468, USA. michael.lafountaine@gmail.com
Radulovic
Miroslav
M
Cardozo
Christopher P
CP
Spungen
Ann M
AM
DeMeersman
Ronald E
RE
Bauman
William A
WA
D000328:Adult; D000704:Analysis of Variance; D001794:Blood Pressure / Q000187:drug effects; D001810:Blood Volume / Q000187:drug effects; D016022:Case-Control Studies; D002908:Chronic Disease; D004791:Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007866:Leg / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology / Q000627:therapeutic use*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D010991:Plethysmography / Q000379:methods; D011782:Quadriplegia / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D014655:Vascular Resistance / Q000187:drug effects*
D004791:Enzyme Inhibitors; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester