Document Detail


Circadian entrainment to light-dark cycles involves extracellular nitric oxide communication within the suprachiasmatic nuclei.
MedLine Citation:
PMID:  20180840     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The ability to synchronize to light-dark (LD) cycles is an essential property of the circadian clock, located in mammals within the hypothalamic suprachiasmatic nuclei (SCN). Single light pulses activate nitric oxide (NO) intracellular signaling, leading to circadian phase-shifts required for synchronization. In addition, extracellular NO has a role in the SCN paracrine communication of photic phase advances. In this work, the extracellular nitrergic transmission was assessed in steady-state synchronization to LD cycles of locomotor rhythms in the golden hamster (Mesocricetus auratus). Extracellular NO levels were pharmacologically decreased in vivo with the specific scavenger, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO). Hamsters were subjected to LD cycles different from normal 24 h (LD 14 : 10) cycles (i.e. T-cycles), with a single 30-min light pulse presented either every 23 h (T23 cycles), or every 25 h (T25 cycles), thus allowing synchronization by advances or delays, respectively. Acute PTIO intracerebroventricular microinjections, delivered 30 min previous to the light pulse, inhibited synchronization by phase advances to T23 cycles, but did not alter phase delays under T25 cycles. In addition, NO scavenging inhibited light-induced expression of PERIOD1 protein at circadian time 18 (i.e. the time for light-induced phase advances). These findings demonstrate the role of extracellular NO communication within the SCN in the steady-state synchronization to LD cycles.
Authors:
Santiago A Plano; Diego A Golombek; Juan J Chiesa
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-02-17
Journal Detail:
Title:  The European journal of neuroscience     Volume:  31     ISSN:  1460-9568     ISO Abbreviation:  Eur. J. Neurosci.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-04-08     Completed Date:  2010-07-12     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8918110     Medline TA:  Eur J Neurosci     Country:  France    
Other Details:
Languages:  eng     Pagination:  876-82     Citation Subset:  IM    
Affiliation:
Department of Science and Technology, Laboratory of Chronobiology, National University of Quilmes/CONICET, Buenos Aires, Argentina.
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MeSH Terms
Descriptor/Qualifier:
Animals
Behavior, Animal / physiology
Biological Clocks / physiology*
Cell Communication / physiology
Circadian Rhythm / physiology*
Cricetinae
Extracellular Fluid / metabolism
Immunohistochemistry
Male
Mesocricetus
Motor Activity / physiology
Nitric Oxide / metabolism*
Photoperiod*
Suprachiasmatic Nucleus / metabolism*
Chemical
Reg. No./Substance:
10102-43-9/Nitric Oxide

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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