title: Orthostatic responses to nitric oxide synthase inhibition in persons with tetraplegia.
abstract: OBJECTIVE
  To determine the effects of 1.0 mg/kg nitro-L-arginine methyl ester (L-NAME) on orthostatic mean arterial pressure (MAP), serum aldosterone, and plasma renin concentrations in persons with chronic tetraplegia compared with nonspinal cord-injured controls.
  
  
  METHODS
  Prospective placebo-controlled intervention study.
  
  
  METHODS
  James J. Peters Veterans Affairs Medical Center.
  
  
  METHODS
  Patients (n=5) with tetraplegia and controls (n=7) participated. The groups were matched for age, height, and weight; the average duration of injury in the tetraplegia group was 22+/-14 years.
  
  
  METHODS
  Subjects with tetraplegia visited the laboratory twice, receiving placebo on day 1 and L-NAME (1.0 mg/kg) on day 2. The agents were infused via an intravenous catheter over 60 minutes with the patient in the supine position. Data were collected during the infusion and then during head-up tilt to 45 degrees for 30 minutes. Control subjects visited the laboratory once for placebo infusion and the head-up tilt maneuver.
  
  
  METHODS
  Orthostatic MAP.
  
  
  RESULTS
  Orthostatic MAP was reduced after placebo infusion in subjects with tetraplegia compared with controls (69+/-11 vs 89+/-9 mmHg, respectively; P<.01) and compared with L-NAME infusion (90+/-16 mmHg; P<.01). Orthostatic MAP did not differ when comparing the tetraplegia group with controls after L-NAME infusion. Orthostatic aldosterone levels were increased after placebo compared with L-NAME infusion in persons with tetraplegia; plasma renin levels did not differ among the groups.
  
  
  CONCLUSIONS
  These data suggest that nitric oxide synthase inhibition may have clinical potential for treatment of orthostatic hypotension in persons with chronic tetraplegia.
authors: Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, NY 10468, USA. jm.wecht@VA.gov
authors: Jill M
authors: JM
authors: Wecht
authors: Miroslav
authors: M
authors: Radulovic
authors: Michael F
authors: MF
authors: Lafountaine
authors: Dwindally
authors: D
authors: Rosado-Rivera
authors: Run-Lin
authors: RL
authors: Zhang
authors: William A
authors: WA
authors: Bauman
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001794:Blood Pressure / Q000187:drug effects*; D016022:Case-Control Studies; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007024:Hypotension, Orthostatic / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D010919:Placebos; D011446:Prospective Studies; D011782:Quadriplegia / Q000201:enzymology*; D013119:Spinal Cord Injuries / Q000188:drug therapy*; D018667:Tilt-Table Test
chemical_list: D010919:Placebos; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester