Contents

Disclaimer

Oxford University Press makes no representation, express or implied, that the drug dosages in this book are correct. Readers must therefore always check the product information and clinical procedures with the most up to date published product information and data sheets provided by the manufacturers and the most recent codes of conduct and safety regulations. The authors and the publishers do not accept responsibility or legal liability for any errors in the text or for the misuse or misapplication of material in this work. Except where otherwise stated, drug dosages and recommendations are for the non-pregnant adult who is not breastfeeding.

Show Summary Details
Page of

Pineal physiology and pathophysiology, including pineal tumours 

Pineal physiology and pathophysiology, including pineal tumours
Chapter:
Pineal physiology and pathophysiology, including pineal tumours
Author(s):

Anna Aulinas

, Cristina Colom

, and Susan M. Webb

DOI:
10.1093/med/9780199235292.003.2222
Page of

PRINTED FROM OXFORD MEDICINE ONLINE (www.oxfordmedicine.com). © Oxford University Press, 2016. All Rights Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in Oxford Medicine Online for personal use (for details see Privacy Policy and Legal Notice).

date: 22 November 2019

The pineal gland is innervated mainly by sympathetic nerve fibres that inform the gland of the prevailing light-dark cycle and acts as a neuroendocrine transducer. The gland is located behind the third ventricle in the centre of the brain and is a highly vascular organ formed by neuroglial cells and parenchymal cells or pinealocytes. The latter synthesize melatonin as well as other indoleamines and peptides.

The main pineal hormone melatonin (N-acetyl-5-methoxytryp-tamine) exhibits an endogenous circadian rhythm, reflecting signals originating in the suprachiasmatic nucleus; environmental lighting entrains the rhythm, by altering its timing. Independently of sleep, pineal melatonin is inhibited by light and stimulated during darkness, thanks to the neural input by a multisynaptic pathway that connects the retina, through the suprachiasmatic nucleus of the hypothalamus, preganglionic neurons in the upper thoracic spinal cord and postganglionic sympathetic fibres from the superior cervical ganglia, with the pineal gland.

Melatonin deficiency may produce sleeping disorders, behavioural problems, or be associated with precocious or delayed puberty in children, while chronically elevated melatonin has been observed in some cases of hypogonadotropic hypogonadism (1, 2).

Access to the complete content on Oxford Medicine Online requires a subscription or purchase. Public users are able to search the site and view the abstracts for each book and chapter without a subscription.

Please subscribe or login to access full text content.

If you have purchased a print title that contains an access token, please see the token for information about how to register your code.

For questions on access or troubleshooting, please check our FAQs, and if you can't find the answer there, please contact us.