The exposure of helically cut strips of aorta of spontaneously hypertensive rats (SHR) and Wistar Kyoto normotensive control strain rats (WKY) to 6(N, N-diethylamino)hexyl 3,4,5-trimethoxybenzoate (TMB-6) blocked norepinephrine (NE, 0.08–0.4 μM) induced contractions. The tension developed in the SHR aorta was lower than that developed in the aorta of WKY rats at equal doses of NE. All doses of TMB-6 decreased responses to low and high levels of NE, indicating a noncompetitive antagonism. The ED50 value with TMB-6 WKY rat aorta was 110 μM and for SHR aorta was 38 μM. Microsomal calcium uptake in rat aorta reflected sarcoplasmic reticulum calcium sequestration. A calcium uptake of 70 nmol/mg protein/60 min was observed with WKY rat aorta microsomes. Calcium uptake of 50 nmol/mg protein/60 min was observed with microsomes prepared from SHR rat aorta. TMB-6 (1 mill) depressed the microsomal calcium uptake in 60 min by only 15% and had no effect on the release of calcium from the preloaded microsomes. The increased sensitivity of SHR aorta to TMB-6 was compatible with a decreased internal calcium store in the SHR aorta reflected in the decreased calcium uptake of the sarcoplasmic reticulum and an increased dependency on influx of external medium calcium blocked by TBM-6. The experimental findings did not indicate a significant effect by TMB-6 on sarcoplasmic reticulum calcium uptake or release. TMB-6 may interfere with the inflow of medium calcium into the smooth muscle cells which is utilized for contraction or may also interfere with the signal to the sarcoplasmic reticulum for release of calcium.

Copyright / Drug Dosage / Disclaimer
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.
You do not currently have access to this content.