title: Metabolic cycles are linked to the cardiovascular diurnal rhythm in rats with essential hypertension.
abstract: BACKGROUND
  The loss of diurnal rhythm in blood pressure (BP) is an important predictor of end-organ damage in hypertensive and diabetic patients. Recent evidence has suggested that two major physiological circadian rhythms, the metabolic and cardiovascular rhythms, are subject to regulation by overlapping molecular pathways, indicating that dysregulation of metabolic cycles could desynchronize the normal diurnal rhythm of BP with the daily light/dark cycle. However, little is known about the impact of changes in metabolic cycles on BP diurnal rhythm.
  
  
  RESULTS
  To test the hypothesis that feeding-fasting cycles could affect the diurnal pattern of BP, we used spontaneously hypertensive rats (SHR) which develop essential hypertension with disrupted diurnal BP rhythms and examined whether abnormal BP rhythms in SHR were caused by alteration in the daily feeding rhythm. We found that SHR exhibit attenuated feeding rhythm which accompanies disrupted rhythms in metabolic gene expression not only in metabolic tissues but also in cardiovascular tissues. More importantly, the correction of abnormal feeding rhythms in SHR restored the daily BP rhythm and was accompanied by changes in the timing of expression of key circadian and metabolic genes in cardiovascular tissues.
  
  
  CONCLUSIONS
  These results indicate that the metabolic cycle is an important determinant of the cardiovascular diurnal rhythm and that disrupted BP rhythms in hypertensive patients can be normalized by manipulating feeding cycles.
authors.affiliation: Department of Physiology, Wakayama Medical University School of Medicine, Wakayama, Japan.
authors.forename: He
authors.initials: H
authors.lastname: Cui
authors.forename: Akira
authors.initials: A
authors.lastname: Kohsaka
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Waki
authors.forename: Mohammad E R
authors.initials: ME
authors.lastname: Bhuiyan
authors.forename: Sabine S
authors.initials: SS
authors.lastname: Gouraud
authors.forename: Masanobu
authors.initials: M
authors.lastname: Maeda
mesh_terms: D000818:Animals; D056926:CLOCK Proteins / Q000235:genetics / Q000378:metabolism; D002320:Cardiovascular Physiological Phenomena / Q000235:genetics; D002940:Circadian Rhythm / Q000235:genetics / Q000502:physiology*; D005215:Fasting / Q000378:metabolism / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005943:Gluconeogenesis / Q000235:genetics; D006339:Heart Rate / Q000502:physiology; D006973:Hypertension / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology*; D050155:Lipogenesis / Q000235:genetics; D008297:Male; D008660:Metabolism / Q000235:genetics / Q000502:physiology; D017440:Photoperiod; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
chemical_list: D056926:CLOCK Proteins; C538945:Clock protein, rat