Blog
About

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

      Creatine and Cyclocreatine Effects on Ischemic Myocardium: 31P Nuclear Magnetic Resonance Evaluation of Intact Heart

      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 purpose of this study was to investigate the effects of prior dietary supplementation with creatine (Cr) or cyclocreatine (Cy, a synthetic analogue of Cr) on high energy phosphate metabolism of the ischemic myocardium. To this end, 48 rats were fed the following powdered rat chow diet for 21 days: 16 were fed chow without additives (CON); 16 were fed a diet containing 1 % Cr by weight (CR); 16 were fed a diet containing 1 % Cy by weight (CY). At the end of the feeding period, rats were anesthetized, hearts harvested and perfused in the Langendorff mode using Krebs-Henseleit buffer (maintained at 37 °C, equilibrated with 95% 02/5% CO2) to which 11 mM glucose was added. <sup>31</sup>P nuclear magnetic resonance (NMR) studies of myocardial bioenergetics were done using a Bruker AM 500 spectrometer. After acquisition of preischemic spectra, global ischemia was produced by clamping aortic inflow. Ischemia was maintained until adenosine triphosphate (ATP) became NMR invisible (CON =34 ± llmin;CR = 32 ± 13min;CY = 56 ± 13min;p < 0.05 CY vs. CR and CON). Half-lives of ATP were 19 min for CON and CR and 37.5 min for CY; half-lives of phosphagen were 4 min for CON and CR and 11 min for CY. Time for return of mechanical function (heart rate × systolic pressure) after ischemia was similar for all three groups (CON = 28 ± 28, CR = 34 ± 22, and CY = 22 ± 15 min), even though the CY group was subjected to longer periods of ischemia). These data indicate that CY, but not CR, pretreatment provides myocardial protection either during and/or after ischemia and allows return of mechanical function after much longer episodes of ischemia than in CON and CR. One factor in the mechanism of protection may be the prolonged maintenance of phosphagen due to the higher equilibrium concentration of phosphocyclo-creatine which in turn provides substrate for continued synthesis of ATP during and after ischemia, thus defining Cy as a bioenergetic protective agent. Other mechanisms of protection remain to be defined.

          Related collections

          Author and article information

          Journal
          CRD
          Cardiology
          10.1159/issn.0008-6312
          Cardiology
          S. Karger AG
          0008-6312
          1421-9751
          1992
          1992
          12 November 2008
          : 80
          : 3-4
          : 184-195
          Affiliations
          Departments of aMedicine (Cardiology), bAnesthesia and cBiochemistry/Biophysics, University of Pennsylvania, Philadelphia, Pa.; dDepartment of Chemistry, University of Lowell, Mass., USA
          Article
          175002 Cardiology 1992;80:184–195
          10.1159/000175002
          1511465
          © 1992 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: 12
          Categories
          General Cardiology, Basic Research

          Comments

          Comment on this article