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Noninvasive Measure of Microvascular Nitric Oxide Function in Humans Using Very Low‐Frequency Cutaneous Laser Doppler Flow Spectra
Author(s) -
Stewart Julian M.,
Taneja Indu,
Goligorsky Michael S.,
Medow Marvin S.
Publication year - 2007
Publication title -
microcirculation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.793
H-Index - 83
eISSN - 1549-8719
pISSN - 1073-9688
DOI - 10.1080/10739680601139179
Subject(s) - laser doppler velocimetry , nitric oxide , chemistry , doppler effect , very low frequency , cholinergic , acetylcholine , blood flow , stimulation , medicine , physics , astronomy
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.