Acetylcholine, Ca 2+  Overload and Oscillatory Potentials in Isolated Ventricular Myocytes

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 events caused by overdrive-induced calcium overload were studied in guinea pig isolated ventricular myocytes. Overdrive may induce oscillatory potentials (Vos) and a prolonged depolarization (Vex), as well as the underlying currents (Ios and Iex, respectively). Acetylcholine (ACh) reduced or abolished these events, an action which was blocked by atropine. Norepinephrine exaggerated the effects of overdrive, and ACh markedly antagonized such an enhancement. Caffeine at low concentrations increased both Ios and Iex whereas at high concentrations caffeine abolished Ios but increased Iex. Quinacrine abolished both events. Voltage clamp depolarizing steps abolished Ios (and did not reverse it). Thus, the effects of Ca overload are antagonized by ACh in the absence and presence of sympathetic enhancement. Also, the mechanism underlying Ios appears to involve an electrogenic Ca extrusion and not an increase in a nonspecific conductance.

Related collections

Author and article information

Journal

Journal ID (publisher-id): CRD

Journal ID (nlm-ta): Cardiology

Journal ID (doi): 10.1159/issn.0008-6312

Title: Cardiology

Publisher: S. Karger AG

ISSN (Print): 0008-6312

ISSN (Electronic): 1421-9751

Publication date Subscription-year: 1991

Publication date (Print): 1991

Publication date (Electronic): 12 November 2008

Volume: 79

Issue: 1

Pages: 20-30

Affiliations

Department of Physiology, State University of New York, Health Science Center, Brooklyn, N.Y., USA

Article

Publisher ID: 174853 Other ID: Cardiology 1991;79:20–30

DOI: 10.1159/000174853

PubMed ID: 1777911

SO-VID: c91d3bd1-ac3b-4edd-acf9-8f173934ff09

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.

History

Date received : 01 February 1991

Date accepted : 11 February 1991

Page count

Pages: 11

Comments

Comment on this article

scite_

Acetylcholine, Ca ²⁺ Overload and Oscillatory Potentials in Isolated Ventricular Myocytes

Read this article at