Blog
About

0
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found

      Hyperosmolarity Enhances Smooth Muscle Contractile Responses to Phenylephrine and Partially Impairs Nitric Oxide Production in the Rat Tail Artery

      Read this article at

      ScienceOpenPublisherPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The respective effects of hyperosmolarity caused by impermeant solutes, such as mannitol and sucrose, on the endothelium and smooth muscles cell responses were investigated in the rat tail artery. The vessels, with or without endothelium, were infused and superfused with an isosmolar saline solution, and were repeatedly stimulated with phenylephrine. Superfusing with hyperosmolar fluid (390–420 mosm/l) produced a transient increase in the arterial basal perfusion pressure which peaked after approximately 5 min and then declined within 15 min to a stable nonsignificant value above control values in subsequent experiments. In arteries with functional endothelium, the effect of phenylephrine was about 1.9-fold larger in hyperosmotic medium compared to that in isosmotic medium. In hyperosmotic media the response was still more than twofold enhanced in endothelium-denuded vessels compared to those with endothelium. In the latter, indomethacin (10 µ M) had no effect, but N<sup>ω</sup>-nitro- L-arginine methylester ( L-NAME; 30 µmol/l), an inhibitor of NO production, enhanced the response to phenylephrine to reach the same magnitude of response as seen in endothelium-denuded arteries. This effect of L-NAME was antagonized by L-arginine. Relaxation induced by the NO donor SIN-1 was unchanged by hyperosmolarity, indicating that the effect of NO was not impaired. It is concluded that, in the rat tail artery, the enhancement in phenylephrine-induced contractions produced in a hyperosmolar solution is due to both an endothelium-independent increase in smooth muscle responses and a moderate decrease in the production of NO, or an NO-like factor, by the endothelium. In spite of this reduction, endothelium-derived NO still plays a major role in attenuating phenylephrine-induced contractions in hyperosmolar medium.

          Related collections

          Author and article information

          Journal
          JVR
          J Vasc Res
          10.1159/issn.1018-1172
          Journal of Vascular Research
          S. Karger AG
          1018-1172
          1423-0135
          1995
          1995
          24 September 2008
          : 32
          : 1
          : 58-65
          Affiliations
          Laboratoire de Pharmacologie et Physiopathologie Cellulaires, CNRS URA 600, Université Louis-Pasteur, Strasbourg, France
          Article
          159078 J Vasc Res 1995;32:58–65
          10.1159/000159078
          7873711
          © 1995 S. Karger AG, Basel

          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
          Pages: 8
          Categories
          Research Paper

          Comments

          Comment on this article