Levels of monoamines and indices of monoaminergic function were evaluated in basal forebrain nuclei [vertical diagonal band nucleus (vDB), horizontal diagonal band nucleus (hDB), nucleus basalis (nbM), medial septal nucleus (mS)] and in other brain areas of female young (3-month-old) and aged (24-month-old) Fischer 344 rats. Concentrations of norepinephrine (NE) decreased 25–60% in the vDB, nbM, mS, and locus coeruleus (LC) of aged rats as compared to young rats. Dopamine (DA) and serotonin (5-HT) levels were unchanged in basal forebrain nuclei of aged rats. Using α-methyl-p-tyrosine, an inhibitor of tyrosine hydroxylase, to evaluate catecholaminergic function showed that NE turnover, an index of NE release over time, decreased 66% in the nbM, 40% in the mS, and 83 % in the LC of aged rats. DA turnover decreased approximately 30% in the vDB, mS, and striatum of aged rats. In contrast, the activity of 5-HT endings, assessed by 5-hydroxyindole-acetic acid (5-HIAA) levels and 5-HIAA/5-HT ratios, increased in the hDB and nbM. These results raise the possibility that age-related decreases in catecholaminergic function within basal forebrain nuclei, which are critical for memory function, may contribute to age-related cognitive impairments.

This content is only available via PDF.
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.