Mélatonine, Rythme circadien, Noyau suprachiasmatiqu et Glande pinéale



La mélatonine  souvent dénommée hormone du sommeil, est surtout connue comme étant l hormone centrale de régulation des rythmes chronobiologiques en étant synthétisée surtout la nuit. Elle est sécrétée par la glande pinéale en réponse à l'absence de lumière. De nombreux aspects du comportement des mammifères comportent un rythme circadien (le sommeil, l'activité physique, la vigilance, les taux d'hormones, la température du corps, les fonctions immunitaires et la digestion). Le NSC contrôle les rythmes circadiens. Dans le cas du sommeil, par exemple, la durée totale est maintenue chez les rats avec une lésion du NSC mais la durée et l'organisation des phases de sommeil deviennent imprévisibles.

Melatonin receptors as therapeutic targets in the suprachiasmatic nucleus.

Expert Opin Ther Targets. 2016 Apr 15;
Authors: Pévet P

Abstract
INTRODUCTION: Disorders of rhythmicity can cause a variety of pathologies and are known to impair processes involved in metabolism, as well as in cardiovascular disease and cancer. Developing strategies to treat or prevent such diseases is a new challenge for medicine. Rhythms depend on a complex multi-oscillatory circadian network which, in mammals, is hierarchically organized with the suprachiasmatic nuclei (SCN) as master clock. The SCN, thus form an ideal structure for target discovery in circadian pathologies. Areas covered: The development of strategies to treat or prevent disorders of rhythmicity is a new challenge for medicine. Several pharmacological approaches have been suggested, but until now, it has been mostly melatonin ( mélatonine ) (MTL) or MTL-agonists which have demonstrated usefulness in modulating clock activities in vivo. A great number of structurally different MTL receptor ligands have been developed, some of which are already approved and marketed as drugs. The MTL receptor involved in phase-shifting circadian rhythms (chronobiotic effect) is the MT1 subtype. Expert opinion: As the two receptor subtypes for MTL may have divergent functions, the development of highly selective MT1 and MT2 agonists (and antagonists) is key for the discovery of novel therapeutic agents in specifically defined circadian pathologies. The identification of cells expressing the different MTL receptor subtypes should also permit a better understanding of MLT physiology/pharmacology.

PMID: 27082492 [PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/27082492?dopt=Abstract



Melatonine - Multilenguages section Key Melatonin