Evidence for a specific influence of the nitrergic pathway on the peripheral pulse waveform in rabbits

B.A. Nier, Louise Harrington, Martin J. Carrier, P.D. Weinberg

Research output: Contribution to journalArticle

Abstract

The height of the dicrotic notch between the systolic and diastolic peaks of the peripheral pulse wave, expressed as a fraction of the overall amplitude of the wave, is sensitive to nitric oxide (NO) bioactivity. This phenomenon might form the basis of a simple, non-invasive method for determining endothelial function in vivo. We assessed whether the phenomenon is specific to the NO pathway or whether other vasoactive agents have similar effects. The relative height of the dicrotic notch (RHDN) was determined by photoplethysmography in the rabbit ear. It was dose-dependently decreased by acetylcholine, a stimulator of endothelial NO synthesis, and increased by N(G)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthesis. There was no effect on RHDN of the alpha-adrenergic blocker phentolamine or the beta-adrenergic blocker propranolol. The cyclo-oxygenase inhibitor indomethacin dose-dependently decreased RHDN but this effect was blocked by L-NAME, suggesting it was mediated by cross-talk with the NO pathway. Changes in RHDN appeared to be independent of heart rate and of the delay between the systolic peak and the notch, but were associated with changes in the slope of the dicrotic limb. Both L-NAME and phentolamine produced multiple diastolic peaks, indicative of wave reflections in the vasculature. These data support the view that changes in RHDN are specific to the NO pathway and provide additional information about the mechanisms involved.
Original languageEnglish
Pages (from-to)503-512
Number of pages10
JournalExperimental Physiology
Volume93
Issue number4
DOIs
Publication statusPublished - 25 Jan 2008

Fingerprint Dive into the research topics of 'Evidence for a specific influence of the nitrergic pathway on the peripheral pulse waveform in rabbits'. Together they form a unique fingerprint.

Cite this