title: Augmented Blood Pressure Variability in Hypertension Induced by Angiotensin II in Rats.
abstract: BACKGROUND
  Augmented blood pressure (BP) variability is associated with cardiovascular diseases in some clinical conditions including hypertension. Drugs that effectively reduce BP variability need to be identified, while few animal models are currently available to study BP variability. Here, we report that hypertension induced by continuous infusion of angiotensin II (Ang II) was accompanied by increased BP variability in rats.
  
  
  METHODS
  Ang II was subcutaneously infused at a rate of 240 pmol/kg/min into male Wistar rats undergoing intraperitoneal implantation of a transmitter connected to an abdominal aortic catheter. BP was continuously monitored via a telemetry system before and after the Ang II infusion in a conscious, unrestrained condition. BP variability was evaluated by coefficient of variation (CV) of BP levels measured every 15 minutes. In addition, spontaneously hypertensive and Wistar-Kyoto rats (SHR and WKY) were subjected to the BP monitoring experiment at 15 weeks of age.
  
  
  RESULTS
  Both systolic and diastolic BP levels were significantly elevated following the Ang II infusion. Similarly, CVs of systolic and diastolic BP in the Ang II infusion group were significantly higher than in the vehicle group upon 1 and 2 weeks of the infusion. Meanwhile, CVs of systolic and diastolic BP of SHR were in a range similar to those of WKY despite significantly higher BP than in WKY.
  
  
  CONCLUSIONS
  Hypertension induced by the continuous infusion of Ang II was accompanied by augmented BP variability in rats, an effect assumed to be at least in part, independent of BP elevation.
authors.affiliation: Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan;
authors.forename: Danfeng
authors.initials: D
authors.lastname: Jiang
authors.affiliation: Department of Internal Medicine, University of Miyazaki Faculty of Medicine, Miyazaki, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Tokashiki
authors.affiliation: Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan;
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Hayashi
authors.affiliation: Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan;
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kawagoe
authors.affiliation: Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan;
authors.forename: Kenji
authors.initials: K
authors.lastname: Kuwasako
authors.affiliation: Department of Internal Medicine, University of Miyazaki Faculty of Medicine, Miyazaki, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kitamura
authors.affiliation: Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan; jkjpn@med.miyazaki-u.ac.jp.
authors.forename: Johji
authors.initials: J
authors.lastname: Kato
mesh_terms: D000804:Angiotensin II; D000818:Animals; D001794:Blood Pressure; D004195:Disease Models, Animal; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology*; D008297:Male; D011918:Rats, Inbred SHR; D017208:Rats, Wistar
chemical_list: D000804:Angiotensin II
keywords: Wistar-Kyoto rats.; angiotensin II infusion; blood pressure variability; hypertension; rat model of hypertension; spontaneously hypertensive rats