Current-Induced Vasodilation during Water Iontophoresis (5 min, 0.10 mA) Is Delayed from Current Onset and Involves Aspirin Sensitive Mechanisms

Abstract

Study of the microcirculation by iontophoresis is potentially confounded by any non-specific effects of current application. Laser Doppler flow (LDF, mean ± SD; arbitrary units; AU) was recorded on the forearms of healthy volunteers during and 20 min following application of 0.10-mA current for 1, 3 and 5 min, using deionised water as a vehicle. Local heating to 44°C was then applied for 24 min to assess maximal vasodilation. Cathodal current applications resulted in delayed and prolonged vasodilation (peak values: 78 ± 29, 75 ± 19, 80 ± 37 AU) whereas anodal peak LDF was 13 ± 6, 27 ± 34 and 72 ± 40 AU for 1-, 3- and 5-min periods of current applications, respectively. From current onset, inflexion points in the responses to 3- and 5-min anodal current applications occurred at 4.5 and 6.5 min, respectively, and at ∼1.5 min for all cathodal current applications. For 5-min current applications: a preliminary tourniquet ischaemia neither changed the time course nor the amplitude of the response to current application. In this situation, local anaesthesia abolished the current-induced vasodilation. Chronic capsaicin pretreatment decreased the amplitude of the vasodilation. Pretreatment with 500 mg oral aspirin decreased the cathodal vasodilation and abolished the anodal vasodilation, even in the absence of preliminary ischaemia. We conclude that vasodilation to prolonged application of 0.10-mA continuous monopolar current after transient tourniquet ischaemia cannot be exclusively the result of an axon reflex initiated by current onset. This current-induced vasodilation is at least partly dependent on capsaicin-sensitive afferent fibres and relies on aspirin-sensitive mechanisms at both polarities.

Journal

Journal ID (publisher-id): JVR

Journal ID (nlm-ta): J Vasc Res

Journal ID (doi): 10.1159/issn.1018-1172

Title: Journal of Vascular Research

Publisher: S. Karger AG

ISSN (Print): 1018-1172

ISSN (Electronic): 1423-0135

Publication date Subscription-year: 2002

Publication date (Print): February 2002

Publication date (Electronic): 13 February 2002

Volume: 39

Issue: 1

Pages: 59-71

Affiliations

Laboratory of Physiology, University Hospital, Angers, France

Article

Publisher ID: 48994 Other ID: J Vasc Res 2002;39:59–71

DOI: 10.1159/000048994

PubMed ID: 11844938

Copyright statement: © 2002 S. Karger AG, Basel

License:

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher. Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug. Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

Page count

Figures: 5, Tables: 2, References: 71, Pages: 13

Product

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Categories

Subject: Research Paper