J Physiol Boston Smyposia
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Physiol Volume 586, Number 16, 4017-4027, August 15, 2008 DOI: 10.1113/jphysiol.2008.154351
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
586/16/4017    most recent
jphysiol.2008.154351v1
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Google Scholar
Right arrow Articles by Torres-Farfan, C.
Right arrow Articles by Seron-Ferre, M.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Torres-Farfan, C.
Right arrow Articles by Seron-Ferre, M.
Related Collections
Right arrow Integrative

INTEGRATIVE

Evidence of a role for melatonin in fetal sheep physiology: direct actions of melatonin on fetal cerebral artery, brown adipose tissue and adrenal gland

 Claudia Torres-Farfan1, Francisco J. Valenzuela1, Mauricio Mondaca1, Guillermo J. Valenzuela2, Bernardo Krause1, Emilio A. Herrera1,3, Raquel Riquelme1, Anibal J. Llanos1,3,4 and Maria Seron-Ferre1,4

1 Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
2 Women's Health, Arrowhead Regional Medical Center, Colton, CA, USA
3 International Center for Andean Studies, Universidad de Chile, Chile
4 Universidad de Tarapaca, Arica, Chile

Although the fetal pineal gland does not secrete melatonin, the fetus is exposed to melatonin of maternal origin. In the non-human primate fetus, melatonin acts as a trophic hormone for the adrenal gland, stimulating growth while restraining cortisol production. This latter physiological activity led us to hypothesize that melatonin may influence some fetal functions critical for neonatal adaptation to extrauterine life. To test this hypothesis we explored (i) the presence of G-protein-coupled melatonin binding sites and (ii) the direct modulatory effects of melatonin on noradrenaline (norepinephrine)-induced middle cerebral artery (MCA) contraction, brown adipose tissue (BAT) lypolysis and ACTH-induced adrenal cortisol production in fetal sheep. We found that melatonin directly inhibits the response to noradrenaline in the MCA and BAT, and also inhibits the response to ACTH in the adrenal gland. Melatonin inhibition was reversed by the melatonin antagonist luzindole only in the fetal adrenal. MCA, BAT and adrenal tissue displayed specific high-affinity melatonin binding sites coupled to G-protein (Kd values: MCA 64 ± 1 pM, BAT 98.44 ± 2.12 pM and adrenal 4.123 ± 3.22 pM). Melatonin binding was displaced by luzindole only in the adrenal gland, supporting the idea that action in the MCA and BAT is mediated by different melatonin receptors. These direct inhibitory responses to melatonin support a role for melatonin in fetal physiology, which we propose prevents major contraction of cerebral vessels, restrains cortisol release and restricts BAT lypolysis during fetal life.

(Received 20 March 2008; accepted after revision 26 June 2008; first published online 3 July 2008)
Corresponding author M. Serón-Ferré: Salvador 486, Providencia, Santiago, Chile, Departamento de Fisiopatología, ICBM, Facultad de Medicina, Universidad de Chile, Casilla 16038, Santiago 9, Santiago, Chile. Email: mseron{at}med.uchile.cl






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2008 The Physiological Society.