Diurnal Regulation of the Gastrin-releasing Peptide Receptor in the Mouse Circadian Clock.
From: Department of Psychology, Columbia University, New York, NY 10027, USA.
The European journal of neuroscience
- Publish Date: Feb 2006
- ISSN: 0953-816X
- Volume: 23
- Issue: 4
- Pages: 1047-53
- Medium: Print
- Language: English
- Citation (JAMA): Karatsoreos Ilia N, Romeo Russell D, McEwen Bruce S, et al. Diurnal Regulation of the Gastrin-releasing Peptide Receptor in the Mouse Circadian Clock.. Eur. J. Neurosci. Feb 2006;23:1047-53
Abstract
In mammals, circadian rhythms are generated by the suprachiasmatic nuclei (SCN) of the hypothalamus. SCN neurons are heterogeneous and can be classified according to their function, anatomical connections, morphology and/or peptidergic identity. We focus here on gastrin-releasing peptide- (GRP) and on GRP receptor- (GRPr) expressing cells of the SCN. Pharmacological application of GRP in vivo or in vitro can shift the phase of circadian rhythms, and GRPr-deficient mice show blunted photic phase shifting. Given the in vivo and in vitro effects of GRP on circadian behavior and on SCN neuronal activity, we investigated whether the GRPr might be under circadian and/or diurnal control. Using in situ hybridization and autoradiographic receptor binding, we localized the GRPr in the mouse SCN and determined that GRP binding varies with time of day in animals housed in a light-dark cycle but not in conditions of constant darkness. The latter results were confirmed with Western blots of SCN tissue. Together, the present findings reveal that changes in GRPr are light driven and not endogenously organized. Diurnal variation in GRPr activity probably underlies intra-SCN signaling important for entrainment and phase shifting.
Mesh Headings (Keywords): Analysis of Variance, Animals, Arginine Vasopressin, Blotting, Western, Circadian Rhythm, Gastrin-Releasing Peptide, Gene Expression Regulation, In Situ Hybridization, Iodine Isotopes, Mice, Mice, Inbred C57BL, Neurons, RNA, Messenger, Radioligand Assay, Receptors, Bombesin, Suprachiasmatic Nucleus
Check for Full Text / PubMed Unique Identifier (PMID): 16519669
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