title: Noninvasive measure of microvascular nitric oxide function in humans using very low-frequency cutaneous laser Doppler flow spectra.
abstract: OBJECTIVE
  While higher frequency oscillations (0.021-0.6 Hz) in cutaneous blood flow measured by laser Doppler flowmetry (LDF) relate to oscillations in blood pressure and sympathetic nerve activity, very low-frequency oscillations (VLF, 0.0095-0.021 Hz) do not. The authors investigated whether VLF LDF power is nitric oxide (NO) specific.
  
  
  METHODS
  LDF combined with intradermal microdialysis was used in the calves of 22 healthy volunteers aged 19-27 years. LDF power spectral analysis was performed by windowed fast Fourier transform. The authors tested whether the NO synthesis inhibitor nitro-l-arginine (NLA) produced selective decreases in VLF power before and after stimulation with acetylcholine.
  
  
  RESULTS
  NLA alone did not alter total power but selectively reduced VLF power by approximately 50%. LDF and spectral power increased markedly across all spectra with acetylcholine. This increase was blunted by NLA, which selectively reduced VLF power by approximately 50%.
  
  
  CONCLUSIONS
  The data suggest that VLF oscillations in the laser Doppler signal are NO dependent, increase with cholinergic stimulation, and have potential as a noninvasive marker for NO-dependent microvascular reactivity.
authors: New York Medical College, Valhalla, New York, USA. stewart@nymc.edu
authors: Julian M
authors: JM
authors: Stewart
authors: Indu
authors: I
authors: Taneja
authors: Michael S
authors: MS
authors: Goligorsky
authors: Marvin S
authors: MS
authors: Medow
mesh_terms: D000109:Acetylcholine / Q000008:administration & dosage*; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D009569:Nitric Oxide / Q000097:blood*; D019335:Nitroarginine / Q000008:administration & dosage*; D012867:Skin / Q000098:blood supply / Q000378:metabolism; D013564:Sympathetic Nervous System / Q000502:physiology; D014665:Vasodilator Agents / Q000008:administration & dosage*
chemical_list: D004791:Enzyme Inhibitors; D014665:Vasodilator Agents; D019335:Nitroarginine; D009569:Nitric Oxide; D000109:Acetylcholine