Document Detail

Spontaneous c-Fos rhythm in the rat suprachiasmatic nucleus: location and effect of photoperiod.
MedLine Citation:
PMID:  11080094     Owner:  NLM     Status:  MEDLINE    
A recently reported circadian rhythm in the spontaneous c-Fos immunoreactivity in the rat suprachiasmatic nucleus (SCN) is expressed mostly in the dorsomedial (dm) SCN, where vasopressinergic cells are located. The aim of the present study is to find out whether day length, i.e., photoperiod, affects the dm-SCN rhythm and, if so, how the rhythm adjusts to a change from a long to a short photoperiod. In addition, a question of whether the spontaneous c-Fos production is localized in vasopressin- producing cells or in other cells is also studied to characterize further the dm-SCN rhythmicity. Combined immunostaining for c-Fos and arginine vasopressin (AVP) revealed that most of c-Fos immunopositive cells were devoid of AVP; the results suggest that c-Fos-producing cells in the dm-SCN are mostly not identical with those producing AVP. In rats maintained under a long photoperiod with 16:8-h light-dark cycle (LD 16:8) daily and then released into darkness, the time of the afternoon and evening decline of the spontaneous c-Fos immunoreactivity in the dm-SCN differed just slightly from the time in rats maintained originally under a short LD 8:16 photoperiod; however, the morning c-Fos rise occurred about 4 h earlier under the long than under the short photoperiod. After a change from a long to a short photoperiod, a rough but not yet a fine adjustment of the morning c-Fos rise to the change was accomplished within 3-6 days. The results show that similar to the recently reported ventrolateral SCN rhythmicity, the intrinsic dm-SCN rhythmicity is also affected by the photoperiod and suggest that the whole SCN state is photoperiod dependent.
A Sumová; Z Trávnícková; H Illnerová
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  279     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2000 Dec 
Date Detail:
Created Date:  2000-12-14     Completed Date:  2000-12-14     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  R2262-9     Citation Subset:  IM    
Institute of Physiology, Academy of Sciences of the Czech Republic, 142 20 Prague 4, Czech Republic.
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MeSH Terms
Arginine Vasopressin / analysis
Circadian Rhythm / physiology*
Gene Expression Regulation / physiology*
Genes, fos*
Neurons / cytology,  physiology
Proto-Oncogene Proteins c-fos / analysis
Rats, Wistar
Suprachiasmatic Nucleus / cytology,  physiology*
Reg. No./Substance:
0/Proto-Oncogene Proteins c-fos; 113-79-1/Arginine Vasopressin

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