The effect of apomorphine (80 µg/kg s.c.) and oxytocin (30 ng i.c.v.) on penile erection and yawning was studied in intact and castrated male rats. In castrated rats both apomorphine and oxytocin responses were abolished. In these animals, testosterone (100 µg/kg s.c. once a day for 3 days), restored penile erection while estradiol benzoate (10 µg/kg s.c. once a day for 3 days) restored yawning induced by both compounds. 5-Dihydrotestosterone (DHT) or progesterone (each at a dose of 100 µg/kg s.c. once a day for 3 days) were ineffective. Given together, estradiol benzoate and DHT partially restored apomorphine- and oxytocin-induced yawning and penile erection, whereas estradiol benzoate and progesterone restored only yawning. Estradiol benzoate-induced recovery of yawning was prevented by the antiestrogen tamoxifen (1 mg/kg s.c. once a day for 3 days). In intact rats, progesterone increased and estradiol benzoate decreased apomorphine- and oxytocin-induced yawning without modifying penile erection, although oxytocin-induced yawning was prevented much less by estradiol benzoate than that induced by apomorphine. Testosterone or DHT were ineffective on both responses. Estradiol benzoate inhibition of apomorphine- and oxytocin-induced yawning was prevented by tamoxifen, which per se failed to modify apomorphine and oxytocin responses, as well as by testosterone or progesterone. The present results suggest that apomorphine-and oxytocin-induced penile erection and yawning are endocrine-dependent and differentially modulated by sexual steroids, suggesting that the mechanisms controlling the two behaviors are different even though they are often associated.

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.