MT1 melatonin receptor mRNA expression exhibits a circadian variation in the rat suprachiasmatic nuclei

The aim of the present study was to investigate the daily regulation of both MT1 and MT2 melatonin receptor subtype mRNA expression in the rat SCN in order to clarify their role in the daily variation of SCN melatonin receptors. Existing MT1 and MT2 partial clones were extended by PCR to 982 and 522...

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Bibliographic Details
Published in:Brain research 2002-08, Vol.946 (1), p.64-71
Main Authors: Poirel, Vincent-Joseph, Masson-Pévet, Mireille, Pevét, Paul, Gauer, François
Format: Article
Language:English
Subjects:
Amino Acid Sequence - genetics
Animals
Base Sequence - genetics
Biological and medical sciences
Circadian clock
Circadian Rhythm
Fundamental and applied biological sciences. Psychology
Hormones and neuropeptides. Regulation
Hypothalamus. Hypophysis. Epiphysis. Urophysis
Male
Melatonin
Melatonin receptor
Molecular Sequence Data
MT1 mRNA
Rats
Rats, Wistar
Receptors, Cell Surface - genetics
Receptors, Cytoplasmic and Nuclear - genetics
Receptors, Melatonin
RNA, Messenger - metabolism
Suprachiasmatic nucleus
Suprachiasmatic Nucleus - metabolism
Vertebrates: endocrinology
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Summary:The aim of the present study was to investigate the daily regulation of both MT1 and MT2 melatonin receptor subtype mRNA expression in the rat SCN in order to clarify their role in the daily variation of SCN melatonin receptors. Existing MT1 and MT2 partial clones were extended by PCR to 982 and 522 bp, respectively. However, while the MT1 clone allowed us to set up a highly sensitive in situ hybridization (ISH) method, we could not detect MT2 expression within the SCN. Therefore, our results suggest that only MT1 mRNA can be correlated with 2-iodo-melatonin binding sites in the rat SCN. Investigation of MT1 mRNA expression throughout the 24 h light/dark cycle or in constant darkness clearly showed that in the two conditions, mRNA expression showed a robust rhythm with two peaks, one after the day/night and one after the night/day transitions in LD, and at the beginning of the subjective night and day in DD, respectively. Furthermore, these variations were not linked to the daily changes in melatonin receptor density. Thus, the transcriptional regulation of MT1 receptors does not appear to play a role in the daily regulation of melatonin binding sites availability.
ISSN:0006-8993
1872-6240
DOI:10.1016/S0006-8993(02)02824-X