title: Impaired blood pressure compensation following hemorrhage in conscious obese Zucker rats.
abstract: OBJECTIVE
  Hemorrhagic shock leads to a higher risk of mortality and morbidity in obese patients, however the mechanisms for these outcomes are unclear. We hypothesized that following severe hemorrhage, blood pressure control in conscious obese Zucker rats (OZ) is impaired.
  
  
  METHODS
  Experiments were performed in conscious lean Zucker rats (LZ) and OZ. Blood pressure, heart rate, cardiac output, total peripheral resistance (TPR), plasma renin activity (PRA), plasma antidiuretic hormone (ADH), and blood gasses were measured before and after severe hemorrhage (35% of the total blood volume).
  
  
  RESULTS
  Basal blood pressure, cardiac output, TPR, PRA, and ADH levels were not different between LZ and OZ. Compared to LZ, OZ exhibited impaired baroreflex control of heart rate and showed higher levels of vascular adrenergic tone. One hour after the hemorrhage, LZ and OZ exhibited similar decreases in cardiac output. However, blood pressure, heart rate, TPR, PRA, and ADH levels were lower in OZ than in LZ.
  
  
  CONCLUSIONS
  These results indicate that conscious OZ has impaired blood pressure compensation after hemorrhage due to a blunted increase in TPR. This is due at least in part to an impaired regulation of vasoconstrictor hormones. To our knowledge, the current study is the first to demonstrate that hemodynamic responses and associated hormone secretion are impaired in a conscious obese model.
authors.affiliation: Department of Physiology and Biophysics University of Mississippi Medical Center.
authors.forename: Lusha
authors.initials: L
authors.lastname: Xiang
authors.affiliation: Department of Physiology and Biophysics University of Mississippi Medical Center.
authors.forename: John S
authors.initials: JS
authors.lastname: Clemmer
authors.affiliation: Department of Physiology and Biophysics University of Mississippi Medical Center.
authors.forename: Silu
authors.initials: S
authors.lastname: Lu
authors.affiliation: Department of Physiology and Biophysics University of Mississippi Medical Center.
authors.forename: Peter N
authors.initials: PN
authors.lastname: Mittwede
mesh_terms: D000818:Animals; D017704:Baroreflex / Q000235:genetics; D001794:Blood Pressure / Q000235:genetics*; D003243:Consciousness / Q000502:physiology*; D006339:Heart Rate / Q000235:genetics; D006439:Hemodynamics / Q000235:genetics*; D006470:Hemorrhage / Q000150:complications / Q000235:genetics / Q000503:physiopathology*; D008297:Male; D009765:Obesity / Q000235:genetics / Q000503:physiopathology*; D051381:Rats; D011924:Rats, Zucker
keywords: Antidiuretic hormone; Baroreflex; Cardiac output; Hemorrhage; Obesity; Renin; Sympathetic nerve; Vascular resistance