title: Age-related changes in control of blood pressure and heart rate during sleep in the rat.
abstract: OBJECTIVE
  The aim of this study was to determine age-related changes in the control of mean arterial pressure (MAP) and heart rate (HR) during sleep, and its relationship to the baroreflex in aging.
  
  
  METHODS
  MAP, HR, body temperature (TP), spontaneous activity (ACT), and sleeping/waking duration were monitored for 24 hours in groups of young (10-12 wk old) and old (23-24 mo old) rats.
  
  
  METHODS
  The sleep laboratory at the University of Tokushima.
  
  
  METHODS
  Subjects were 8 young (10-12 wk old) and 7 old (23-24 mo old) Wistar rats.
  
  
  METHODS
  Reflex control of HR was evaluated by examining various pressure responses to an intravenous bolus injection of phenylephrine and sodium nitroprusside.
  
  
  RESULTS
  MAP and TP were recorded by a radiotelemetry system. HR was detected from the AP signal. ACT was counted by a photo-sensor system. In the case of old rats, the sensitivity of baroreflex control of HR was significantly depressed, and the spontaneous increase of MAP and HR during REM sleep and the MAP drop at the end of REM sleep were significantly enhanced. The old rats showed no large deterioration of the circadian profiles of MAP, HR, TP, and the amount of sleep.
  
  
  CONCLUSIONS
  The baroreflex dysfunction is considered to appear in an early stage of the aging process, and to affect the control of MAP and HR during sleep.
authors: Department of Physiology, School of Medicine, The University of Tokushima, Japan. sei@basic.med.tokushima-u.ac.jp
authors: Hiroyoshi
authors: H
authors: Sei
authors: Atsuko
authors: A
authors: Sano
authors: Hiromi
authors: H
authors: Ohno
authors: Kazue
authors: K
authors: Yamabe
authors: Yasuhiko
authors: Y
authors: Nishioka
authors: Saburo
authors: S
authors: Sone
authors: Yusuke
authors: Y
authors: Morita
mesh_terms: D000367:Age Factors; D000375:Aging / Q000502:physiology*; D000818:Animals; D017704:Baroreflex / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D001831:Body Temperature / Q000502:physiology; D004567:Electrodes, Implanted; D004569:Electroencephalography; D006339:Heart Rate / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012890:Sleep / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology