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      Vasoconstrictor and Dilator Actions of Nicotine and Electrical Transmural Stimulation on Isolated Dog Cerebral Arteries

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          Abstract

          Effects of nicotine and electrical transmural stimulation on isolated dog cerebral arteries were studied. Nicotine (5 × 10<sup>–8</sup>–10<sup>–4</sup> m) usually evoked a phasic contraction in the basilar artery and a relaxation in the middle cerebral artery. The nicotine-induced contraction and relaxation were abolished by pretreatment with pentolinium (10<sup>–5</sup> m) but not by tetrodotoxin (TTX) (10<sup>–7</sup> m). Phentolamine (10<sup>–6</sup> m) or bretylium (10<sup>–5</sup> m) abolished or reversed the nicotine-induced contraction, and partially reduced the nicotine-induced relaxation. Electrical transmural stimulation elicited a phasic contraction in the basilar artery and a relaxation or slight contraction in the middle cerebral artery. The contraction induced by transmural stimulation was abolished by bretylium and TTX, and augmented by phentolmine. The relaxation was not inhibited by bretylium. The uptake of <sup>3</sup>H-norepinephrine (<sup>3</sup>H-NE) by the basilar and middle cerebral arteries was markedly reduced by cocaine (3 × 10<sup>–6</sup> m). Nicotine and transmural stimulation increased the tritium efflux from both arteries. The nicotine-induced increase in tritium efflux was inhibited by pentolinium. The increased efflux induced by transmural stimulation was abolished by TTX, attenuated by bretylium, and augmented by phentolamine. These results indicate that nicotine and transmural stimulation cause both vasoconstrictor and vasodilator effects in the dog cerebral arteries and that the vasoconstriction is mediated through an adrenergic mechanism.

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          Author and article information

          Journal
          JVR
          J Vasc Res
          10.1159/issn.1018-1172
          Journal of Vascular Research
          S. Karger AG
          978-3-8055-2857-3
          978-3-318-02028-1
          1018-1172
          1423-0135
          1978
          1978
          18 September 2008
          : 15
          : 1-3
          : 110-118
          Affiliations
          Department of Pharmacology, Faculty of Medicine, Kyoto University, Kyoto
          Article
          158157 Blood Vessels 1978;15:110–118
          10.1159/000158157
          © 1978 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: 9
          Categories
          Molecular and Cellular Aspects of Vascular Smooth Muscle in Health and Disease

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