Document Detail

Altered circadian rhythms of corticosterone, melatonin, and phagocytic activity in response to stress in rats.
MedLine Citation:
PMID:  17693961     Owner:  NLM     Status:  MEDLINE    
Corticosterone is thought to be the main glucocorticoid secreted in response to stressful exercise, while melatonin buffers the adverse immunological effects of stress. The present work was aimed to evaluate whether swimming-exercise-induced stress leads to changes in the chronobiology parameters of the circadian rhythms of melatonin and corticosterone, and in the number and phagocytosis of peritoneal macrophages in 3-month-old male Wistar rats. The animals were subjected to a physical activity trial consisting of 2 h of free swimming. Radioimmunoassay was used to determine the plasma levels of melatonin and corticosterone. Phagocytosis was measured by the latex-bead phagocytosis index (PI), i.e., the number of latex beads ingested by 100 macrophages, the phagocytosis percentage (PP), i.e., the percentage of cells that had phagocytosed at least one latex bead, and the phagocytosis efficiency (PE), i.e., the ratio PI: PP which indicates how effectively the phagocytes ingested the particles. Stress significantly decreased the MESOR and amplitude of the melatonin rhythm, and significantly increased the MESOR of the corticosterone rhythm. The control animals' peritoneal macrophage number and PI showed a circadian rhythm with maxima at 02:00 and 03:00, respectively. The stressed group displayed higher values of PI than the controls at most hours of the night, but the number of cells in the peritoneal cavity was practically the same at all hours studied. These data confirm that melatonin and corticosterone act as modulators of the innate immune response, and that the circadian rhythm of the two hormones are altered in situations of stress.
Sergio D Paredes; Soledad Sánchez; Hasan Parvez; Ana B Rodríguez; Carmen Barriga
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Neuro endocrinology letters     Volume:  28     ISSN:  0172-780X     ISO Abbreviation:  Neuro Endocrinol. Lett.     Publication Date:  2007 Aug 
Date Detail:
Created Date:  2007-11-06     Completed Date:  2008-01-24     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8008373     Medline TA:  Neuro Endocrinol Lett     Country:  Sweden    
Other Details:
Languages:  eng     Pagination:  489-95     Citation Subset:  IM    
Department of Physiology, Faculty of Science, University of Extremadura, Avenida de Elvas s/n, 06071 Badajoz, Spain
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Cell Count
Circadian Rhythm / physiology*
Corticosterone / blood*
Immune System / physiology
Macrophages / pathology,  physiology
Melatonin / blood*
Peritoneal Cavity / cytology
Phagocytosis / physiology*
Physical Conditioning, Animal / physiology
Rats, Wistar
Stress, Physiological / pathology,  physiopathology*
Swimming / physiology
Reg. No./Substance:
50-22-6/Corticosterone; 73-31-4/Melatonin

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

Previous Document:  Chrononutrition applied to formula milks to consolidate infants' sleep/wake cycle.
Next Document:  Effect of carbimazole induced hypothyroidism and thyroxine replacement on the growth of the long bon...