Document Detail

Neuropeptide Y differentially suppresses per1 and per2 mRNA induced by light in the suprachiasmatic nuclei of the golden hamster.
MedLine Citation:
PMID:  11837945     Owner:  NLM     Status:  MEDLINE    
Neuropeptide Y (NPY), present in an input pathway to the suprachiasmatic nuclei (SCN), can block the effects of light on circadian rhythms. The authors have studied this interaction using an in vitro brain slice technique. Effects of NPY on light-induced period1 and period2 mRNA in the SCN were examined in vitro following a light pulse during early subjective night. Golden hamsters (n = 91) were housed under a 14:10 LD cycle and then moved to constant dim red light for 3 days. Hamsters were exposed to a 5-min light pulse previously shown to induce phase shifts and prepared for in vitro application of NPY. Hypothalamic slices containing the SCN were maintained in vitro for 40 min to 4 h after the light pulse, then quick-frozen. Sections were evaluated by in situ hybridization with [35S]-labeled cRNA probes for per mRNA. Rapid light induction of both per1 and per2 by 40 min and 1 h after the light pulse, respectively, was apparent, with NPY inhibition of this response significant by at least these same time points. However, although striking suppression of per2 mRNA by the NPY continued through the peak for per2 at 2 h, per1 mRNA levels rebounded quickly to equal the per1 induction peak at 1 h and mirrored the control light induction pattern for per1 thereafter. Delaying NPY to 30 min after slice preparation demonstrated that NPY is capable of suppressing peak per1 levels. These results confirm the feasibility of measuring light-induced gene expression in the SCN in vitro. A differential regulation of per1 and per2 transcription might be of critical importance for the modulation of circadian responses to light.
Judy McKinley Brewer; Paola C Yannielli; Mary E Harrington
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of biological rhythms     Volume:  17     ISSN:  0748-7304     ISO Abbreviation:  J. Biol. Rhythms     Publication Date:  2002 Feb 
Date Detail:
Created Date:  2002-02-11     Completed Date:  2002-07-23     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  8700115     Medline TA:  J Biol Rhythms     Country:  United States    
Other Details:
Languages:  eng     Pagination:  28-39     Citation Subset:  IM    
Neuroscience Program, Smith College, Northampton, MA 01063, USA.
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MeSH Terms
Cell Cycle Proteins
Circadian Rhythm / physiology
DNA Probes
Gene Expression Regulation / drug effects*
In Situ Hybridization
Neuropeptide Y / pharmacology*
Nuclear Proteins / biosynthesis*
Period Circadian Proteins
Photic Stimulation
RNA, Messenger / biosynthesis*
Suprachiasmatic Nucleus / drug effects,  metabolism*
Transcription Factors
Grant Support
Reg. No./Substance:
0/Cell Cycle Proteins; 0/DNA Probes; 0/Neuropeptide Y; 0/Nuclear Proteins; 0/Per2 protein, mouse; 0/Period Circadian Proteins; 0/RNA, Messenger; 0/Transcription Factors

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