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Characteristics of the pulse waveform during altered nitric oxide synthesis in the rabbit
Author(s) -
Weinberg P D,
Habens F,
Kengatharan M,
Barnes S E,
Matz J,
Änggård E E,
Carrier M J
Publication year - 2001
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0704084
Subject(s) - acetylcholine , pulse (music) , chemistry , pulse wave , medicine , nitric oxide , endocrinology , blood pressure , photoplethysmogram , preload , waveform , hemodynamics , physics , optics , detector , computer science , laser , filter (signal processing) , quantum mechanics , voltage , computer vision
Nitrovasodilators produce characteristic changes in the shape of the peripheral pulse wave. Similar changes might also be caused by alteration of endogenous NO activity, which would allow such activity to be assessed in vivo . We investigated whether manipulation of the NO pathway influences the pulse waveform, and the mechanisms involved. The pulse wave in the ear of normal rabbits was examined by reflectance photoplethysmography before and during infusion of vasoactive agents. Pulse wave velocity was assessed by using an additional sensor on the rear foot. A diastolic peak was observed in the ear pulse; its timing was consistent with it being a reflection of the systolic peak from the lower body. The height of the dicrotic notch marking the start of this diastolic wave was decreased by acetylcholine or an NO donor, and further decreased by a phosphodiesterase type V inhibitor. The acetylcholine‐induced decreases were blocked by inhibiting NO synthesis with N G ‐nitro‐ L ‐arginine methyl ester ( L ‐NAME) but were unaffected by the inactive enantiomer D ‐NAME. These data demonstrate that NO influences the height of the notch in the pulse wave. Heart rate and blood pressure were altered during acetylcholine or L ‐NAME infusion, but there were no changes in pulse wave amplitude or velocity, or in the timing of the diastolic peak or dicrotic notch. The slope of the pulse wave between the systolic peak and notch changed substantially. These effects are most convincingly explained by changes in wave reflection, not only from the lower body but also from more proximal sites.British Journal of Pharmacology (2001) 133 , 361–370; doi: 10.1038/sj.bjp.0704084