title: The effect of propranolol on aortic structure and function in normotensive rats.
abstract: BACKGROUND
  Beta-blocking agents are widely used for the treatment of many cardiovascular diseases. The effect of these agents, however, on the aortic wall structure and function has not been well defined. The present study was undertaken to investigate the effect of therapy with propranolol on wall structure and aortic function in rats.
  
  
  METHODS
  20 healthy Wistar rats (350-400 g) were assigned to a control group (n=8), with rats receiving only water and food, and an experimental group (n=12), in which 100 mg/kg/day propranolol was administered in the drinking water. Three months after initiation of treatment, aortic pressures and aortic pulse wave velocity (PWV) were measured using high-fidelity Millar catheters. Extensive histopathologic studies were performed in the wall of the descending thoracic aorta.
  
  
  RESULTS
  Systolic, mean, diastolic, and pulse pressure were significantly lower in the propranolol-treated rats compared to controls (p<0.05). For any given systolic, mean, and pulse pressure, PWV was greater in the propranolol-treated animals (p<0.05). The heart rate was lower and the response to isoproterenol infusion was less in the propranolol-treated animals. Smooth muscle content was decreased and collagen content was increased in the aortic wall of the propranolol-treated animals compared to controls.
  
  
  CONCLUSIONS
  Long-term propranolol administration elicits an increase in PWV adjusted for aortic pressure. This may be related to accumulation of collagen in the aortic wall at the expense of smooth muscle cells. The aortic stiffening may explain some of the reported data, suggesting that the effect of β-blockade therapy in patients with arterial hypertension may be inferior to other pharmacologic agents.
authors.affiliation: Foundation of Biomedical Research, Academy of Athens, Greece. konlampropoulos@yahoo.gr
authors.forename: Konstantinos M
authors.initials: KM
authors.lastname: Lampropoulos
authors.forename: Dimitrios P
authors.initials: DP
authors.lastname: Sokolis
authors.forename: Constantinos A
authors.initials: CA
authors.lastname: Dimitriou
authors.forename: Michalis
authors.initials: M
authors.lastname: Katsimpoulas
authors.forename: Evangelos
authors.initials: E
authors.lastname: Balafas
authors.forename: Anna
authors.initials: A
authors.lastname: Agapaki
authors.forename: Panayotis E
authors.initials: PE
authors.lastname: Karayannacos
authors.forename: Harisios
authors.initials: H
authors.lastname: Boudoulas
mesh_terms: D000284:Administration, Oral; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage*; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D001018:Aortic Diseases / Q000139:chemically induced* / Q000473:pathology / Q000503:physiopathology; D001794:Blood Pressure / Q000187:drug effects; D004195:Disease Models, Animal; D004334:Drug Administration Schedule; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000473:pathology; D011433:Propranolol / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar; D059289:Vascular Stiffness / Q000187:drug effects*
chemical_list: D000319:Adrenergic beta-Antagonists; D011433:Propranolol